February 24, 2011

Marx and Natural Science of Society

By Lil Joe

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Adaoma posts Niose's straw man attack on Marx:

"...Marx's analysis especially welcome and refreshing, for it attempts to set aside all such prejudices in an effort to objectively and scientifically assess the history of human events. When one fairly considers Marx, however, one quickly sees the difficulty of the naturalistic task that Marx set out to accomplish. For even though Marx attempts to analyze history from a naturalistic viewpoint, he falls into several traps that reveal shortcomings in his analysis.

"One such shortcoming is Marx's tendency toward what might be called human exceptionalism. That is, any naturalistic consideration of human history would necessarily require a thorough analysis of the first fundamental fact about human existence the fact that humans are animals. As an animal species humans are defined by their biological characterizations, and any understanding of the human condition, including its history, starts with an understanding of the biological reality of human existence. This biological reality is not just the physical reality of needing food, water and shelter, but also the biological reality of having a brain, and therefore a mind and psyche, that has developed via natural selection. Thus the human animal, in even the strictest materialist analysis, carries with it psychological traits (the fight-or-flight instinct, the tendencies toward anxiety and depression, the craving for food and comfort beyond what is rationally needed, etc.) that have somehow had survival value for hundreds of thousands of years. Marx, to his credit, attempts to incorporate natural humanity into his analysis, but for the most part he does little more than allude to the primitive, underlying biological nature of humans without incorporating a thorough commentary on that nature into his analysis.

"In fact, any fair assessment would conclude that Marx actually downplays the animal nature of humanity, for when discussing the subject he falls into the common trap of quickly embarking on a discussion of what sets humans apart from other animals. This is what I mean when I refer to the human exceptionalism Marx does not wish to thoroughly consider how humans and other animals are alike, but rather he immediately wants to discuss what is unique about the human animal. Thus, early in his materialist conception of history, we find Marx saying:

"Men can be distinguished from animals by consciousness, by religion or anything else you like. They themselves begin to distinguish themselves from animals as soon as they begin to produce their means of subsistence, a step which is conditioned by their physical organization. By producing their means of subsistence men are indirectly producing their actual material life."

"Note first of all that the paradigm of human exceptionalism is clearly cemented into Marx mind, as is evidenced by his reference to humans being distinguished from animals (whereas from other animals would be more accurate). This makes Marx's analysis especially welcome and refreshing, for it attempts to set aside all such prejudices in an effort to objectively and scientifically assess the history of human events. When one fairly considers Marx, however, one quickly sees the difficulty of the naturalistic task that Marx set out to accomplish. For even though Marx attempts to analyze history from a naturalistic viewpoint, he falls into several traps that reveal shortcomings in his analysis."
http://groups.yahoo.com/group/laborpartypraxis/message/26543

Lil Joe's Response: Since Niose's main point in his straw man argument was that Marx's 'shortcoming', supposedly that of the materialist conception of history, is that he didn't present a discription of Homo sapiens biology and the brain, in connection with 'other animals', one would have expected that Niose would have corrrected this 'shortcoming' by presenting it himself. He didn't. He just asserted it and the human 'mind and psyche', with no empirical analysis of it of his own, none whatsoever.

I will present summaries of what we now know of it from contemporary scientific literature, knowledge of which was unknown in the 19th century when Marx-Engels admitted they didn't have it, but in future should be the basis for any scientific analysis of human Society.

Marx-Engels wrote:

" The premises from which we begin are not arbitrary ones, not dogmas, but real premises from which abstraction can only be made in the imagination. They are the real individuals, their activity and the material conditions under which they live, both those which they find already existing and those produced by their activity. These premises can thus be verified in a purely empirical way.

"The first premise of all human history is, of course, the existence of living human individuals. Thus the first fact to be established is the physical organisation of these individuals and their consequent relation to the rest of nature. Of course, we cannot here go either into the actual physical nature of man, or into the natural conditions in which man finds himself geological, hydrographical, climatic and so on. The writing of history must always set out from these natural bases and their modification in the course of history through the action of men. ... (Marx-Engels op. cit.)

One might expect that Niose would have himself presented the contemporary information on animals and the brain in producing self-consciousness as thinking awareness, but since he didn't do it himself, as Marx insisted must be done by those developing the materialist conception of history, I will present the contemporary findings. NOTE: this is not 18th-19th century materialist speculation concerning the human animal and its 'mind and psyche', nor is it philosophical humanist mystification of this animal's 'mind and psyche', but varifiable findings of 20th -211st century empirical zoology.

"Some biologists study plants, others study microbes, and some study fungi, such as mushrooms. But if you want to study living things that move a bit faster, then major in zoology. Zoologists study animals with and without backbones, from worms, insects, and mollusks to fish, birds, and, of course, mammals."
http://www.collegeboard.com/csearch/majors_careers/profiles/majors/26.0701.html

For further information on Zoology as such see Direct-Science-Zoology @ http://www.sciencedirect.com/science/journal/09442006

Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and independently. All animals are also heterotrophs, meaning they must ingest other organisms for sustenance.

Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago.

Animals have several characteristics that set them apart from other living things. Animals are eukaryotic and mostly multicellular, which separates them from bacteria and most protists. They are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking rigid cell walls. All animals are motile, if only at certain life stages. In most animals, embryos pass through a blastula stage, which is a characteristic exclusive to animals.

Structure

With a few exceptions, most notably the sponges (Phylum Porifera) and Placozoa, animals have bodies differentiated into separate tissues. These include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals. Typically, there is also an internal digestive chamber, with one or two openings. Animals with this sort of organization are called metazoans, or eumetazoans when the former is used for animals in general.

All animals have eukaryotic cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. This may be calcified to form structures like shells , bones, and spicules. During development, it forms a relatively flexible framework upon which cells can move about and be reorganized, making complex structures possible. In contrast, other multicellular organisms, like plants and fungi, have cells held in place by cell walls, and so develop by progressive growth. Also, unique to animal cells are the following intercellular junctions: tight junctions, gap junctions, and desmosomes.

Reproduction and development

Nearly all animals undergo some form of sexual reproduction. They have a few specialized reproductive cells, which undergo meiosis to produce smaller, motile spermatozoa or larger, non-motile ova. These fuse to form zygotes, which develop into new individuals.

Many animals are also capable of asexual reproduction. This may take place through parthenogenesis, where fertile eggs are produced without mating, budding, or fragmentation.

A zygote initially develops into a hollow sphere, called a blastula, which undergoes rearrangement and differentiation. In sponges, blastula larvae swim to a new location and develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement. It first invaginates to form a gastrula with a digestive chamber, and two separate germ layers — an external ectoderm and an internal endoderm. In most cases, a mesoderm also develops between them. These germ layers then differentiate to form tissues and organs.

Food and energy sourcing

All animals are heterotrophs, meaning that they feed directly or indirectly on other living things. They are often further subdivided into groups such as carnivores, herbivores, omnivores, and parasites. Predation is a biological interaction where a predator (a heterotroph that is hunting) feeds on its prey (the organism that is attacked). Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of the prey. The other main category of consumption is detritivory, the consumption of dead organic matter. It can at times be difficult to separate the two feeding behaviours, for example, where parasitic species prey on a host organism and then lay their eggs on it for their offspring to feed on its decaying corpse. Selective pressures imposed on one another has led to an evolutionary arms race between prey and predator, resulting in various antipredator adaptations.

Most animals feed indirectly from the energy of sunlight. Plants use this energy to convert sunlight into simple sugars using a process known as photosynthesis. Starting with the molecules carbon dioxide (CO2) and water (H2O), photosynthesis converts the energy of sunlight into chemical energy stored in the bonds of glucose (C6H12O6) and releases oxygen (O2). These sugars are then used as the building blocks which allow the plant to grow.[11] When animals eat these plants (or eat other animals which have eaten plants), the sugars produced by the plant are used by the animal. They are either used directly to help the animal grow, or broken down, releasing stored solar energy, and giving the animal the energy required for motion. This process is known as glycolysis.

Animals living close to hydrothermal vents and cold seeps on the ocean floor are not dependent on the energy of sunlight. Instead chemosynthetic archaea and bacteria form the base of the food chain.

Animals are generally considered to have evolved from a flagellated eukaryote. Their closest known living relatives are the choanoflagellates, collared flagellates that have a morphology similar to the choanocytes of certain sponges. Molecular studies place animals in a supergroup called the opisthokonts, which also include the choanoflagellates, fungi and a few small parasitic protists. The name comes from the posterior location of the flagellum in motile cells, such as most animal spermatozoa, whereas other eukaryotes tend to have anterior flagella.

The first fossils that might represent animals appear in the Trezona Formation at Trezona Bore, West Central Flinders, South Australia. These fossils are interpreted as being early sponges. They were found in 665-million-year-old rock.

The next oldest possible animal fossils are found towards the end of the Precambrian, around 610 million years ago, and are known as the Ediacaran or Vendian biota. These are difficult to relate to later fossils, however. Some may represent precursors of modern phyla, but they may be separate groups, and it is possible they are not really animals at all.

Aside from them, most known animal phyla make a more or less simultaneous appearance during the Cambrian period, about 542 million years ago. It is still disputed whether this event, called the Cambrian explosion, represents a rapid divergence between different groups or a change in conditions that made fossilization possible.

Some paleontologists suggest that animals appeared much earlier than the Cambrian explosion, possibly as early as 1 billion years ago. Trace fossils such as tracks and burrows found in the Tonian era indicate the presence of triploblastic worms, like metazoans, roughly as large (about 5 mm wide) and complex as earthworms. During the beginning of the Tonian period around 1 billion years ago, there was a decrease in Stromatolite diversity, which may indicate the appearance of grazing animals, since Stromatolites diversity increased when grazing animals went extinct at the End Permian and End Ordovician extinction events, and decreased shortly after the grazer populations recovered. However the discovery that tracks very similar to these early trace fossils are produced today by the giant single-celled protist Gromia sphaerica casts doubt on their interpretation as evidence of early animal evolution.

Groups of animals

The relative number of species contributed to the total by each phylum of animals.

Porifera, Radiata and basal Bilateria

The sponges (Porifera) were long thought to have diverged from other animals early. They lack the complex organization found in most other phyla. Their cells are differentiated, but in most cases not organized into distinct tissues. Sponges typically feed by drawing in water through pores. Archaeocyatha, which have fused skeletons, may represent sponges or a separate phylum. However, a phylogenomic study in 2008 of 150 genes in 29 animals across 21 phyla revealed that it is the Ctenophora or comb jellies which are the basal lineage of animals, at least among those 21 phyla. The authors speculate that sponges—or at least those lines of sponges they investigated—are not so primitive, but may instead be secondarily simplified.

Among the other phyla, the Ctenophora and the Cnidaria, which includes sea anemones, corals, and jellyfish, are radially symmetric and have digestive chambers with a single opening, which serves as both the mouth and the anus. Both have distinct tissues, but they are not organized into organs. There are only two main germ layers, the ectoderm and endoderm, with only scattered cells between them. As such, these animals are sometimes called diploblastic. The tiny placozoans are similar, but they do not have a permanent digestive chamber.

The remaining animals form a monophyletic group called the Bilateria. For the most part, they are bilaterally symmetric, and often have a specialized head with feeding and sensory organs. The body is triploblastic, i.e. all three germ layers are well-developed, and tissues form distinct organs. The digestive chamber has two openings, a mouth and an anus, and there is also an internal body cavity called a coelom or pseudocoelom. There are exceptions to each of these characteristics, however — for instance adult echinoderms are radially symmetric, and certain parasitic worms have extremely simplified body structures.

Genetic studies have considerably changed our understanding of the relationships within the Bilateria. Most appear to belong to two major lineages: the deuterostomes and the protostomes, the latter of which includes the Ecdysozoa, Platyzoa, and Lophotrochozoa. In addition, there are a few small groups of bilaterians with relatively similar structure that appear to have diverged before these major groups. These include the Acoelomorpha, Rhombozoa, and Orthonectida. The Myxozoa, single-celled parasites that were originally considered Protozoa, are now believed to have developed from the Medusozoa as well.

Deuterostomes

Deuterostomes differ from the other Bilateria, called protostomes, in several ways. In both cases there is a complete digestive tract. However, in protostomes, the initial opening (the archenteron) develops into the mouth, and an anus forms separately. In deuterostomes this is reversed. In most protostomes, cells simply fill in the interior of the gastrula to form the mesoderm, called schizocoelous development, but in deuterostomes, it forms through invagination of the endoderm, called enterocoelic pouching. Deuterostomes also have a dorsal, rather than a ventral, nerve chord and their embryos undergo different cleavage.

All this suggests the deuterostomes and protostomes are separate, monophyletic lineages. The main phyla of deuterostomes are the Echinodermata and Chordata. The former are radially symmetric and exclusively marine, such as starfish, sea urchins, and sea cucumbers. The latter are dominated by the vertebrates, animals with backbones. These include fish, amphibians, reptiles, birds, and mammals.

In addition to these, the deuterostomes also include the Hemichordata, or acorn worms. Although they are not especially prominent today, the important fossil graptolites may belong to this group.

The Chaetognatha or arrow worms may also be deuterostomes, but more recent studies suggest protostome affinities.

Ecdysozoa

The Ecdysozoa are protostomes, named after the common trait of growth by moulting or ecdysis. The largest animal phylum belongs here, the Arthropoda, including insects, spiders, crabs, and their kin. All these organisms have a body divided into repeating segments, typically with paired appendages. Two smaller phyla, the Onychophora and Tardigrada, are close relatives of the arthropods and share these traits.

The ecdysozoans also include the Nematoda or roundworms, perhaps the second largest animal phylum. Roundworms are typically microscopic, and occur in nearly every environment where there is water. A number are important parasites. Smaller phyla related to them are the Nematomorpha or horsehair worms, and the Kinorhyncha, Priapulida, and Loricifera. These groups have a reduced coelom, called a pseudocoelom.

The remaining two groups of protostomes are sometimes grouped together as the Spiralia, since in both embryos develop with spiral cleavage.

Platyzoa

Pseudobiceros bedfordi, (Bedford's flatworm) The Platyzoa include the phylum Platyhelminthes, the flatworms. These were originally considered some of the most primitive Bilateria, but it now appears they developed from more complex ancestors. A number of parasites are included in this group, such as the flukes and tapeworms. Flatworms are acoelomates, lacking a body cavity, as are their closest relatives, the microscopic Gastrotricha.

The other platyzoan phyla are mostly microscopic and pseudocoelomate. The most prominent are the Rotifera or rotifers, which are common in aqueous environments. They also include the Acanthocephala or spiny-headed worms, the Gnathostomulida, Micrognathozoa, and possibly the Cycliophora. These groups share the presence of complex jaws, from which they are called the Gnathifera.

Lophotrochozoa

Roman snail, Helix pomatia The Lophotrochozoa include two of the most successful animal phyla, the Mollusca and Annelida. The former, which is the second-largest animal phylum by number of described species, includes animals such as snails, clams, and squids, and the latter comprises the segmented worms, such as earthworms and leeches. These two groups have long been considered close relatives because of the common presence of trochophore larvae, but the annelids were considered closer to the arthropods because they are both segmented. Now, this is generally considered convergent evolution, owing to many morphological and genetic differences between the two phyla.

The Lophotrochozoa also include the Nemertea or ribbon worms, the Sipuncula, and several phyla that have a ring of ciliated tentacles around the mouth, called a lophophore. These were traditionally grouped together as the lophophorates but it now appears that the lophophorate group may be paraphyletic,[48] with some closer to the nemerteans and some to the molluscs and annelids. They include the Brachiopoda or lamp shells, which are prominent in the fossil record, the Entoprocta, the Phoronida, and possibly the Bryozoa or moss animals.

Model organism and Animal testing

Because of the great diversity found in animals, it is more economical for scientists to study a small number of chosen species so that connections can be drawn from their work and conclusions extrapolated about how animals function in general. Because they are easy to keep and breed, the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans have long been the most intensively studied metazoan model organisms, and were among the first life-forms to be genetically sequenced. This was facilitated by the severely reduced state of their genomes, but as many genes, introns, and linkages lost, these ecdysozoans can teach us little about the origins of animals in general. The extent of this type of evolution within the superphylum will be revealed by the crustacean, annelid, and molluscan genome projects currently in progress. Analysis of the starlet sea anemone genome has emphasised the importance of sponges, placozoans, and choanoflagellates, also being sequenced, in explaining the arrival of 1500 ancestral genes unique to the Eumetazoa.

An analysis of the homoscleromorph sponge Oscarella carmela also suggests that the last common ancestor of sponges and the eumetazoan animals was more complex than previously assumed.

Other model organisms belonging to the animal kingdom include the mouse (Mus musculus) and zebrafish (Danio rerio). http://en.wikipedia.org/wiki/Animal

Chordates

Essential Knowledge for Naturalists

Chordates include the vertebrates, or animals with backbones. However, not all chordates are vertebrates. Some chordates, such as the cephalochordates (as described by Berkeley) lack a spinal cord, and hence are not vertebrates.

The term chordate does not refer to the spinal cord, but rather the notocord. This is a stiff but flexible rod that runs the length of an animal at some stage of its life, whether embryonic, or adult. Other essential chordate features include gills, tails, and a nerve cord.

Yes, humans are vertebrates, and hence chordates. No, humans do not have gills or tails. We do have a notocord, and a nerve bundle. Embryonic humans at certain stages of development have gill-like structures, and tails. We lose those as we develop.

To focus in on the most relevant chordates, the vertebrates, there are five classes of vertebrates. These are, in roughly the order of complexity, Fish, Amphibians, Reptiles, Birds, and Mammals. To learn more about each of these important classes of wildlife, follow the links below.

Fish

FIsh are cold-blooded, aquatic vertebrates covered with scales. They spend their entire lifecycle as water-dwelling creatures, and can not breathe air (with few exceptions). In Ohio, there are over 160 known species of fish in our streams, rivers, lakes and ponds. Like any other animal, fish species have certain habitat needs. You can guess the condition of a stream by examining fish caught there. For example, trout are only present in Ohio in certain streams where there is a low sediment load, cool to cold temperatures, gravelly bottom, and pools of adequate depth for over-wintering safely. If you catch a brook trout, or red-sided dace, for example, you know you have a healthy cold-water stream. Learn more about fish at the Ohio Department of Natural Resources web site.

Amphibians

Amphibians are cold-blooded creatures that spend part of their life cycle in water and the remainder on land. These creatures are exclusively freshwater organisms. While some amphibians may tolerate brackish (a mixture of fresh and salt water) water, none are adapted to life in salt water. Examples of amphibians include: frogs, toads, and salamanders. They are adapted to life in moist environments, such as wetlands, ponds, streams, or the forest floor.

Salamanders are lizard-like creatures with four stubby legs and fairly long tails. While looking a bit like a lizard, salamanders are not reptiles. They lack the scales of lizards, and also have the amazing ability to re-grow legs or toes that are lost. Learn more about salamanders by visiting the Ohio Salamander Monitoring Program's web page.

Frogs and toads start out life as fertilized eggs, but soon develop into tadpoles, while have gills and a tail, but no legs. They then metamorphosize into the adult stage, whick breathes through both lungs and skin, but lacks gils. The tail is reabsorbed by the body and legs are formed. Adult frogs are smooth and more or less spend their time in and around fresh water. Toads are dry and warty looking, and tend to spend their adult lives in drier environments than frogs. You can help scientists learn more about frogs by keeping a frog log. To learn more about frogs, check out the Ohio Frog and Toad Web Page.

Reptiles

Reptiles are cold-blooded terrestrial animals with lungs and scales. Included in the class reptilia are snakes, lizards, turtles and crocodilians (alligators and crocodiles). In Ohio lizards, snakes and turtles can be found in appropriate habitats, but it does not stay warm enough during the winter months for crocodilians. http://www.neonaturalist.com/nature/chordates.html

Chordates & Vertebrates

A. Introduction to Chordata

3 principle features

1. a single, hollow nerve cord located along the back. Nerve cord = a single hollow cord along the back that carries sensory & motor impulses; form spinal cord & brain in vertebrates.

2. a rod-shaped notochord. Notochord = rod-shaped structure that forms between the nerve cord & cut during development.

3. pharyngeal (gill) arches, which are located at the throat (pharynx).

Importance of 3 features

1. Dorsal nerve root increases responsiveness to the environment. In the more advanced vertebrates. It became differentiated into the brain and spinal cord.

2. Notochord was the starting point for the development of an internal stabilizing framework, the backbone and skeleton which provided support for locomotion and protection for the spinal cord.

3. The bony structures that support the pharyngeal arches evolved into jaws with teeth, allowing these organisms to feed differently than their ancestors. The pharyngeal arches develop into the gill structures of the fishes and into ear, jaw, and throat structures of the terrestrial vertebrates.

B. Tunicates (sea squirts)-animals which look like a living sac attached to the ocean floor

Resemble chordates in larval stage when look like tadpole, have dorsal nerve cord and notochord, gills.

C. Vertebrates

Most have vertebral column in place of notochord-stack of bones, hole in center to form cylinder surrounding and protecting the dorsal nerve cord.
Some vertebrates have skeletons and vertebral columns composed of cartilage (sharks).
Distinct heads with skulls that encase brain.
Closed circulatory system and heart to pump blood.

1. Agnathans - jawless fish - first vertebrates

2. Cartilaginous fishes-sharks, skates and rays.

Osmoregulation-are living in salt water so must either be at same salt concentration as water or excrete salt.

Most-internal fertilization

3. Bony fishes-live in salt and fresh water.

Internal skeleton
Operculum-protects gills and forces water over the gills.
Closed circulatory systems with blood vessels and pump. Four chambered heart which acts as two chambered heart.
Marine fish maintain salt conc. below ocean. Excrete salt through gills.
Fresh water fish have more internal salt than water. Uptake of salt by gills and in food.
Most external fertilization, lay eggs in which the embryo develops after egg laying.

4. Amphibians-frogs, toads, salamanders, mudpuppies, newts.

Most live in water as young and land as adults. Lay eggs in water or moist place. Lungs inefficient and much gas exchange takes place across the skin and on the surfaces of the mouth.

Heart-3 chambers.

5. Reptiles-crocodiles & alligators, turtles & tortoises, lizards & snakes.

Dry skin covered with scales to help retard water loss.
Heart-septum subdivides the ventricle
Amniotic egg-protects embryo from drying out, nourishes it, enables it to develop outside of water

Ectothermic-take temp. from surroundings

6. Birds-9000 species.

Beaks, wings gizzards, feathers, light hollow bones, highly efficient lungs.
4 chambered heart. Oxygenated blood and deoxygenated blood do not mix.
Endothermic-regulate body temperature internally.
Feathers unique to birds.

7. Mammals-4500 species.

Endothermic, have hair, females secrete milk from mammary glands to feed their young.
4 chambered heart.
Advanced locomotion-legs positioned much farther under the body than those of reptiles and are suspended from limb girdles, which permit great leg mobility.
Specialized teeth-incisors -> cutting, canines -> gripping and tearing, molars -> crushing and breaking.

IV-PRIMATE EVOLUTION

Originally tree-dwelling. Therefore, opposable thumb, flexible limbs & spine
Nails instead of claws
Omnivorous diet
Semi-erect or erect posture
Face flattened without snout, binocular vision -> depth perception,
Complex brain large in relation to body size
Long arms & legs
http://lpc1.clpccd.cc.ca.us/lpc/kmoore/Biology10/lectures/LecChp22.html

Mammals

Mammals are a class in the chordate phylum. Mammals are like other chordates in that they have backbones. Mammals have several distinct characteristics.

* They have hair on their bodies.
* They nurse their young.
* They have live birth rather than laying eggs,

There are several major groups of mammals. Below is a list of these groups and their links on this site:

* Egg Laying Mammals
* Flying Mammals
* Toothless Mammals
* Pouched Mammals
* Flesh-eating Mammals
* Insect Eating Mammals
* Gnawing Mammals (Rodents)
* Hoofed Mammals (Ungulates)
* Trunk Nosed Mammals
* Marine Mammals
* Flexibly Fingered Mammals (Primates)

THE NERVOUS SYSTEM
The Neuron

Nervous tissue is composed of two main cell types: neurons and glial cells. Neurons transmit nerve messages. Glial cells are in direct contact with neurons and often surround them.

Nerve Cells and Astrocyte (SEM x2,250). This image is copyright Dennis Kunkel at www.DennisKunkel.com, used with permission.

The neuron is the functional unit of the nervous system. Humans have about 100 billion neurons in their brain alone! While variable in size and shape, all neurons have three parts. Dendrites receive information from another cell and transmit the message to the cell body. The cell body contains the nucleus, mitochondria and other organelles typical of eukaryotic cells. The axon conducts messages away from the cell body.

Structure of a typical neuron. The image above is from https://drbasmamoussa.wordpress.com/.

Three types of neurons occur. Sensory neurons typically have a long dendrite and short axon, and carry messages from sensory receptors to the central nervous system. Motor neurons have a long axon and short dendrites and transmit messages from the central nervous system to the muscles (or to glands). Interneurons are found only in the central nervous system where they connect neuron to neuron.

Structure of a neuron and the direction of nerve message transmission.
Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.

Some axons are wrapped in a myelin sheath formed from the plasma membranes of specialized glial cells known as Schwann cells. Schwann cells serve as supportive, nutritive, and service facilities for neurons. The gap between Schwann cells is known as the node of Ranvier, and serves as points along the neuron for generating a signal. Signals jumping from node to node travel hundreds of times faster than signals traveling along the surface of the axon. This allows your brain to communicate with your toes in a few thousandths of a second.

Cross section of myelin sheaths that surround axons (TEM x191,175). This image is copyright Dennis Kunkel at www.DennisKunkel.com, used with permission.

Structure of a nerve bundle. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.

The Nerve Message

The plasma membrane of neurons, like all other cells, has an unequal distribution of ions and electrical charges between the two sides of the membrane. The outside of the membrane has a positive charge, inside has a negative charge. This charge difference is a resting potential and is measured in millivolts. Passage of ions across the cell membrane passes the electrical charge along the cell. The voltage potential is -65mV (millivolts) of a cell at rest (resting potential). Resting potential results from differences between sodium and potassium positively charged ions and negatively charged ions in the cytoplasm. Sodium ions are more concentrated outside the membrane, while potassium ions are more concentrated inside the membrane. This imbalance is maintained by the active transport of ions to reset the membrane known as the sodium potassium pump. The sodium-potassium pump maintains this unequal concentration by actively transporting ions against their concentration gradients.

Transmission of an action potential. The above image is from https://secure.wikimedia.org/wikipedia/en/wiki/Action_potential.

Changed polarity of the membrane, the action potential, results in propagation of the nerve impulse along the membrane. An action potential is a temporary reversal of the electrical potential along the membrane for a few milliseconds. Sodium gates and potassium gates open in the membrane to allow their respective ions to cross. Sodium and potassium ions reverse positions by passing through membrane protein channel gates that can be opened or closed to control ion passage. Sodium crosses first. At the height of the membrane potential reversal, potassium channels open to allow potassium ions to pass to the outside of the membrane. Potassium crosses second, resulting in changed ionic distributions, which must be reset by the continuously running sodium-potassium pump. Eventually enough potassium ions pass to the outside to restore the membrane charges to those of the original resting potential.The cell begins then to pump the ions back to their original sides of the membrane.

The action potential begins at one spot on the membrane, but spreads to adjacent areas of the membrane, propagating the message along the length of the cell membrane. After passage of the action potential, there is a brief period, the refractory period, during which the membrane cannot be stimulated. This prevents the message from being transmitted backward along the membrane.

Steps in an Action Potential

1. At rest the outside of the membrane is more positive than the inside.
2. Sodium moves inside the cell causing an action potential, the influx of positive sodium ions makes the inside of the membrane more positive than the outside.
3. Potassium ions flow out of the cell, restoring the resting potential net charges.
4. Sodium ions are pumped out of the cell and potassium ions are pumped into the cell, restoring the original distribution of ions.

Synapses

The junction between a nerve cell and another cell is called a synapse. Messages travel within the neuron as an electrical action potential. The space between two cells is known as the synaptic cleft. To cross the synaptic cleft requires the actions of neurotransmitters. Neurotransmitters are stored in small synaptic vessicles clustered at the tip of the axon.

A synapse. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.

Excitatory Synapse from the Central Nervous System (TEM x27,360). This image is copyright Dennis Kunkel at www.DennisKunkel.com, used with permission.

Arrival of the action potential causes some of the vesicles to move to the end of the axon and discharge their contents into the synaptic cleft. Released neurotransmitters diffuse across the cleft, and bind to receptors on the other cell's membrane, causing ion channels on that cell to open. Some neurotransmitters cause an action potential, others are inhibitory.

Neurotransmitters tend to be small molecules, some are even hormones. The time for neurotransmitter action is between 0,5 and 1 millisecond. Neurotransmitters are either destroyed by specific enzymes in the synaptic cleft, diffuse out of the cleft, or are reabsorbed by the cell. More than 30 organic molecules are thought to act as neurotransmitters. The neurotransmitters cross the cleft, binding to receptor molecules on the next cell, prompting transmission of the message along that cell's membrane. Acetylcholine is an example of a neurotransmitter, as is norepinephrine, although each acts in different responses. Once in the cleft, neurotransmitters are active for only a short time. Enzymes in the cleft inactivate the neurotransmitters. Inactivated neurotransmitters are taken back into the axon and recycled.

Diseases that affect the function of signal transmission can have serious consequences. Parkinson's disease has a deficiency of the neurotransmitter dopamine. Progressive death of brain cells increases this deficit, causing tremors, rigidity and unstable posture. L-dopa is a chemical related to dopamine that eases some of the symptoms (by acting as a substitute neurotransmitter) but cannot reverse the progression of the disease.

The bacterium Clostridium tetani produces a toxin that prevents the release of GABA. GABA is important in control of skeletal muscles. Without this control chemical, regulation of muscle contraction is lost; it can be fatal when it effects the muscles used in breathing.

Clostridium botulinum produces a toxin found in improperly canned foods. This toxin causes the progressive relaxation of muscles, and can be fatal. A wide range of drugs also operate in the synapses: cocaine, LSD, caffeine, and insecticides.

Nervous Systems

Multicellular animals must monitor and maintain a constant internal environment as well as monitor and respond to an external environment. In many animals, these two functions are coordinated by two integrated and coordinated organ systems: the nervous system and the endocrine system.

Three basic functions are prformed by nervous systems:

1. Receive sensory input from internal and external environments
2. Integrate the input
3. Respond to stimuli

Sensory Input

Receptors are parts of the nervous system that sense changes in the internal or external environments. Sensory input can be in many forms, including pressure, taste, sound, light, blood pH, or hormone levels, that are converted to a signal and sent to the brain or spinal cord.

Integration and Output

In the sensory centers of the brain or in the spinal cord, the barrage of input is integrated and a response is generated. The response, a motor output, is a signal transmitted to organs than can convert the signal into some form of action, such as movement, changes in heart rate, release of hormones, etc.

Endocrine Systems

Some animals have a second control system, the endocrine system. The nervous system coordinates rapid responses to external stimuli. The endocrine system controls slower, longer lasting responses to internal stimuli. Activity of both systems is integrated.

Divisions of the Nervous System

The nervous system monitors and controls almost every organ system through a series of positive and negative feedback loops.The Central Nervous System (CNS) includes the brain and spinal cord. The Peripheral Nervous System (PNS) connects the CNS to other parts of the body, and is composed of nerves (bundles of neurons).

Not all animals have highly specialized nervous systems. Those with simple systems tend to be either small and very mobile or large and immobile. Large, mobile animals have highly developed nervous systems: the evolution of nervous systems must have been an important adaptation in the evolution of body size and mobility.

Coelenterates, cnidarians, and echinoderms have their neurons organized into a nerve net. These creatures have radial symmetry and lack a head. Although lacking a brain or either nervous system (CNS or PNS) nerve nets are capable of some complex behavior.

Nervous systems in radially symmetrical animals. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission. Bilaterally symmetrical animals have a body plan that includes a defined head and a tail region. Development of bilateral symmetry is associated with cephalization, the development of a head with the accumulation of sensory organs at the front end of the organism. Flatworms have neurons associated into clusters known as ganglia, which in turn form a small brain. Vertebrates have a spinal cord in addition to a more developed brain.

Some nervous systems in bilaterally symmetrical animals. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman , (www.whfreeman.com)used with permission.

Chordates have a dorsal rather than ventral nervous system. Several evolutionary trends occur in chordates: spinal cord, continuation of cephalization in the form of larger and more complex brains, and development of a more elaborate nervous system. The vertebrate nervous system is divided into a number of parts. The central nervous system includes the brain and spinal cord. The peripheral nervous system consists of all body nerves. Motor neuron pathways are of two types: somatic (skeletal) and autonomic (smooth muscle, cardiac muscle, and glands). The autonomic system is subdivided into the sympathetic and parasympathetic systems.

Scale model of bottlenose dolphin (Tursiops truncatus) brain (middle), compared with brains of wild pig (Sus scrofa) (left), and man (Homo sapiens) (right)

https://secure.wikimedia.org/wikipedia/en/wiki/Brain

Peripheral Nervous System

The Peripheral Nervous System (PNS)contains only nerves and connects the brain and spinal cord (CNS) to the rest of the body. The axons and dendrites are surrounded by a white myelin sheath. Cell bodies are in the central nervous system (CNS) or ganglia. Ganglia are collections of nerve cell bodies. Cranial nerves in the PNS take impulses to and from the brain (CNS). Spinal nerves take impulses to and away from the spinal cord. There are two major subdivisions of the PNS motor pathways: the somatic and the autonomic.

Two main components of the PNS:

1. sensory (afferent) pathways that provide input from the body into the CNS.
2. motor (efferent) pathways that carry signals to muscles and glands (effectors).

Most sensory input carried in the PNS remains below the level of conscious awareness. Input that does reach the conscious level contributes to perception of our external environment.

Somatic Nervous System

The Somatic Nervous System (SNS) includes all nerves controlling the muscular system and external sensory receptors. External sense organs (including skin) are receptors. Muscle fibers and gland cells are effectors. The reflex arc is an automatic, involuntary reaction to a stimulus. When the doctor taps your knee with the rubber hammer, she/he is testing your reflex (or knee-jerk). The reaction to the stimulus is involuntary, with the CNS being informed but not consciously controlling the response. Examples of reflex arcs include balance, the blinking reflex, and the stretch reflex.

Sensory input from the PNS is processed by the CNS and responses are sent by the PNS from the CNS to the organs of the body.

Motor neurons of the somatic system are distinct from those of the autonomic system. Inhibitory signals, cannot be sent through the motor neurons of the somatic system.

Autonomic Nervous System

The Autonomic Nervous System is that part of PNS consisting of motor neurons that control internal organs. It has two subsystems. The autonomic system controls muscles in the heart, the smooth muscle in internal organs such as the intestine, bladder, and uterus. The Sympathetic Nervous System is involved in the fight or flight response. The Parasympathetic Nervous System is involved in relaxation. Each of these subsystems operates in the reverse of the other (antagonism). Both systems innervate the same organs and act in opposition to maintain homeostasis. For example: when you are scared the sympathetic system causes your heart to beat faster; the parasympathetic system reverses this effect.

Motor neurons in this system do not reach their targets directly (as do those in the somatic system) but rather connect to a secondary motor neuron which in turn innervates the target organ.

Central Nervous System

The Central Nervous System (CNS) is composed of the brain and spinal cord. The CNS is surrounded by bone-skull and vertebrae. Fluid and tissue also insulate the brain and spinal cord.

Areas of the brain. The above image is from http://www.prs.k12.nj.us/schools/PHS/Science_Dept/APBio/pic/brain.gif.

The brain is composed of three parts: the cerebrum (seat of consciousness), the cerebellum, and the medulla oblongata (these latter two are "part of the unconscious brain").

The medulla oblongata is closest to the spinal cord, and is involved with the regulation of heartbeat, breathing, vasoconstriction (blood pressure), and reflex centers for vomiting, coughing, sneezing, swallowing, and hiccuping. The hypothalamus regulates homeostasis. It has regulatory areas for thirst, hunger, body temperature, water balance, and blood pressure, and links the Nervous System to the Endocrine System. The midbrain and pons are also part of the unconscious brain. The thalamus serves as a central relay point for incoming nervous messages.

The cerebellum is the second largest part of the brain, after the cerebrum. It functions for muscle coordination and maintains normal muscle tone and posture. The cerebellum coordinates balance.

The conscious brain includes the cerebral hemispheres, which are are separated by the corpus callosum. In reptiles, birds, and mammals, the cerebrum coordinates sensory data and motor functions. The cerebrum governs intelligence and reasoning, learning and memory. While the cause of memory is not yet definitely known, studies on slugs indicate learning is accompanied by a synapse decrease. Within the cell, learning involves change in gene regulation and increased ability to secrete transmitters.

The Brain

During embryonic development, the brain first forms as a tube, the anterior end of which enlarges into three hollow swellings that form the brain, and the posterior of which develops into the spinal cord. Some parts of the brain have changed little during vertebrate evolutionary history.

Parts of the brain as seen from the middle of the brain. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.

Vertebrate evolutionary trends include

1. Increase in brain size relative to body size.
2. Subdivision and increasing specialization of the forebrain, midbrain, and hindbrain.
3. Growth in relative size of the forebrain, especially the cerebrum, which is associated with increasingly complex behavior in mammals.

The Brain Stem and Midbrain

The brain stem is the smallest and from an evolutionary viewpoint, the oldest and most primitive part of the brain. The brain stem is continuous with the spinal cord, and is composed of the parts of the hindbrain and midbrain. The medulla oblongata and pons control heart rate, constriction of blood vessels, digestion and respiration.

The midbrain consists of connections between the hindbrain and forebrain. Mammals use this part of the brain only for eye reflexes.

The Cerebellum

The cerebellum is the third part of the hindbrain, but it is not considered part of the brain stem. Functions of the cerebellum include fine motor coordination and body movement, posture, and balance. This region of the brain is enlarged in birds and controls muscle action needed for flight.

The Forebrain

The forebrain consists of the diencephalon and cerebrum. The thalamus and hypothalamus are the parts of the diencephalon. The thalamus acts as a switching center for nerve messages. The hypothalamus is a major homeostatic center having both nervous and endocrine functions.

The cerebrum, the largest part of the human brain, is divided into left and right hemispheres connected to each other by the corpus callosum. The hemispheres are covered by a thin layer of gray matter known as the cerebral cortex, the most recently evolved region of the vertebrate brain. Fish have no cerebral cortex, amphibians and reptiles have only rudiments of this area.

The cortex in each hemisphere of the cerebrum is between 1 and 4 mm thick. Folds divide the cortex into four lobes: occipital, temporal, parietal, and frontal. No region of the brain functions alone, although major functions of various parts of the lobes have been determined.

The major brain areas and lobes. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.

The occipital lobe (back of the head) receives and processes visual information. The temporal lobe receives auditory signals, processing language and the meaning of words. The parietal lobe is associated with the sensory cortex and processes information about touch, taste, pressure, pain, and heat and cold. The frontal lobe conducts three functions:

1. motor activity and integration of muscle activity
2. speech
3. thought processes

Functional areas of the brain. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.

Most people who have been studied have their language and speech areas on the left hemisphere of their brain. Language comprehension is found in Wernicke's area. Speaking ability is in Broca's area. Damage to Broca's area causes speech impairment but not impairment of language comprehension. Lesions in Wernicke's area impairs ability to comprehend written and spoken words but not speech. The remaining parts of the cortex are associated with higher thought processes, planning, memory, personality and other human activities.

Parts of the cerebral cortex and the relative areas that are devoted to controlling various body regions. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.

The Spinal Cord

The spinal cord runs along the dorsal side of the body and links the brain to the rest of the body. Vertebrates have their spinal cords encased in a series of (usually) bony vertebrae that comprise the vertebral column.

The gray matter of the spinal cord consists mostly of cell bodies and dendrites. The surrounding white matter is made up of bundles of interneuronal axons (tracts). Some tracts are ascending (carrying messages to the brain), others are descending (carrying messages from the brain). The spinal cord is also involved in reflexes that do not immediately involve the brain.

The Brain and Drugs

Some neurotransmitters are excitory, such as acetylcholine, norepinephrine, serotonin, and dopamine. Some are associated with relaxation, such as dopamine and serotonin. Dopamine release seems related to sensations of pleasure. Endorphins are natural opioids that produce elation and reduction of pain, as do artificial chemicals such as opium and heroin. Neurological diseases, for example Parkinson's disease and Huntington's disease, are due to imbalances of neurotransmitters. Parkinson's is due to a dopamine deficiency. Huntington's disease is thought to be cause by malfunctioning of an inhibitory neurotransmitter. Alzheimer's disease is associated with protein plaques in the brain.

Drugs are stimulants or depressants that block or enhance certain neurotransmitters. Dopamine is thought involved with all forms of pleasure. Cocaine interferes with uptake of dopamine from the synaptic cleft. Alcohol causes a euphoric "high" followed by a depression.

Marijuana, material from the Indian hemp plant (Cannabis sativa), has a potent chemical THC (tetrahydracannibinol) that in low, concentrations causes a euphoric high (if inhaled, the most common form of action is smoke inhalation). High dosages may cause severe effects such as hallucinations, anxiety, depression, and psychotic symptoms.

Cocaine is derives from the plant Erthoxylon coca. Inhaled, smoked or injected. Cocaine users report a "rush" of euphoria following use. Following the rush is a short (5-30 minute) period of arousal followed by a depression. Repeated cycle of use terminate in a "crash" when the cocaine is gone. Prolonged used causes production of less dopamine, causing the user to need more of the drug.

Heroin is a derivative of morphine, which in turn is obtained from opium, the milky secretions obtained from the opium poppy, Papaver somniferum. Heroin is usually injected intravenously, although snorting and smoking serve as alternative delivery methods. Heroin binds to ophioid receptors in the brain, where the natural chemical endorphins are involved in the cessation pain. Heroin is physically addictive, and prolonged use causes less endorphin production. Once this happens, the euphoria is no longer felt, only dependence and delay of withdrawal symptoms.

Senses

Input to the nervous system is in the form of our five senses: pain, vision, taste, smell, and hearing. Vision, taste, smell, and hearing input are the special senses. Pain, temperature, and pressure are known as somatic senses. Sensory input begins with sensors that react to stimuli in the form of energy that is transmitted into an action potential and sent to the CNS.

Sensory Receptors

* Sensory receptors are classified according to the type of energy they can detect and respond to.
* Mechanoreceptors: hearing and balance, stretching.
* Photoreceptors: light.
* Chemoreceptors: smell and taste mainly, as well as internal sensors in the digestive and circulatory systems.
* Thermoreceptors: changes in temperature.
* Electroreceptors: detect electrical currents in the surrounding environment.

Mechanoreceptors vary greatly in the specific type of stimulus and duration of stimulus/action potentials. The most adaptable vertebrate mechanoreceptor is the hair cell. Hair cells are present in the lateral line of fish. In humans and mammals hair cells are involved with detection of sound and gravity and providing balance.

Hearing

Hearing involves the actions of the external ear, eardrum, ossicles, and cochlea. In hearing, sound waves in air are converted into vibrations of a liquid then into movement of hair cells in the cochlea. Finally they are converted into action potentials in a sensory dendrite connected to the auditory nerve. Very loud sounds can cause violent vibrations in the membrane under hair cells, causing a shearing or permanent distortion to the cells, resulting in permanent hearing loss.

Orientation and Gravity

Orientation and gravity are detected at the semicircular canals. Hair cells along three planes respond to shifts of liquid within the cochlea, providing a three-dimensional sense of equilibrium. Calcium carbonate crystals can shift in response to gravity, providing sensory information about gravity and acceleration. Photoreceptors Detect Vision and Light Sensitivity

The human eye can detect light in the 400-700 nanometer (nm) range, a small portion of the electromagnetic spectrum, the visible light spectrum. Light with wavelengths shorter than 400 nm is termed ultraviolet (UV) light. Light with wavelengths longer than 700 nm is termed infrared (IR) light.

The electromagnetic spectrum.

Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.

Eye

In the eye, two types of photoreceptor cells are clustered on the retina, or back portion of the eye. These receptors, rods and cones, apparently evolved from hair cells. Rods detect differences in light intensity; cones detect color. Rods are more common in a circular zone near the edge of the eye. Cones occur in the center (or fovea centralis) of the retina.

Light reaching a photoreceptor causes the breakdown of the chemical rhodopsin, which in turn causes a membrane potential that is transmitted to an action potential. The action potential transfers to synapsed neurons that connect to the optic nerve. The optic nerve connects to the occipital lobe of the brain.

Humans have three types of cones, each sensitive to a different color of light: red, blue and green. Opsins are chemicals that bind to cone cells and make those cells sensitive to light of a particular wavelength (or color). Humans have three different form of opsins coded for by three genes on the X chromosome. Defects in one or more of these opsin genes can cause color blindness, usually in males. http://www.emc.maricopa.edu/faculty/farabee/biobk/biobooknerv.html

Animal Intelligence and the Evolution of the Human Mind

Subtle refinements in brain architecture, rather than large-scale alterations, make us smarter than other animals By Ursula Dicke and Gerard Roth | August 28, 2008 |

In Brief

The human brain lacks conspicuous characteristics—such as relative or absolute size—that might account for humans' superior intellect.

Researchers have found some clues to humanity's aptitude on a smaller scale, such as more neurons in our brain's outermost layer.

Human intelligence may be best likened to an upgrade of the cognitive capacities of nonhuman primates rather than an exceptionally advanced form of cognition.

As far as we know, no dog can compose music, no dolphin can speak in rhymes, and no parrot can solve equations with two unknowns. Only humans can perform such intellectual feats, presumably because we are smarter than all other animal species—at least by our own definition of intelligence.

Of course, intelligence must emerge from the workings of the three-pound mass of wetware packed inside our skulls. Thus, researchers have tried to identify unique features of the human brain that could account for our different intellectual abilities. But, anatomically, the human brain is very similar to that of other primates because humans and chimpanzees share an ancestor that walked the earth less than seven million years ago. http://www.scientificamerican.com/article.cfm?id=intelligence-evolved

The Brain Human brain cross section

The brain is probably the most amazing physical structure we know. Nowhere else in the universe do we find anything comparable. People have tried to understand it for thousands of years. The ancient Greeks thought that it acts like a radiator cooling the blood. Medieval philosophers believed that it is the abode of the soul and that it could be invaded by spirits. Today, we think that the brain is responsible for all faculties of mind. The human brain is one of the most intensively researched items in biology, yet there are many questions to which we don't have answers. For example, we don't know how consciousness arises from the brain. Nevertheless, significant advances were made in brain research during the past few decades. From classical neuroanatomy we know the different parts and structures of the brain. From neuropsychology we know their psychological and behavioural functions. From neurophysiology and neurochemistry we know the workings of neurons (brain cells) and their connections.

You may find that the appearance of the human brain is quite unimposing. It doesn't really look like one of the world's wonders, but rather like something you might find washed up on a beach. The human brain is the size of a large grapefruit and weighs 1 – 1.5 kg. The outer visible layer, the cortex, is part of the cerebrum. It comprises two halves, or hemispheres, of highly wrinkled grey matter. The grey matter consists of the cell bodies of neurons, whereas the subjacent white matter consists of nerve fibres (axons) that constitute long distance connections between neurons. The two hemispheres are separated by a deep grove, the longitudinal cerebral fissure. They are connected at the base by the corpus callosum, a thick layer of nerve fibres. At the outer sides of the hemispheres there is another deep grove, the lateral fissure or lateral sulcus, which divides the frontal and parietal lobes from the temporal lobes. Developmentally, the brain can be divided into three main divisions, the hindbrain (rhombencephalon), midbrain (mesencephalon), and forebrain (prosencephalon).

Divisions of the brain.

The three main parts of the brain can be further divided into substructures, as shown in the illustrations. We will first look at these parts from an evolutionary point of view. The brain stem is the oldest part of the brain. It contains the midbrain and the hindbrain minus the cerebellum. It evolved more than 500 million years ago. Because it resembles the brain of a reptile, it is also called the "reptilian brain". The brainstem controls autonomic functions, such as breathing, heart rate, and digestion. The cerebellum, or "little brain", which is attached to the back of the brainstem, is likewise evolutionary ancient. It contains circuits which are similar in all vertebrates, including fish. Its function is to control and adjust posture and to coordinate muscular movement. The expanded human cerebellum also has a role in some cognitive functions, such as attention.

Brain divisions

The limbic system is the group of structures located between the brain stem and the cortex. It evolved between 300 and 200 million years ago and –since it is most highly developed in mammals– it is also called the "mammalian brain". The limbic system is involved in emotion and motivation. For example, the amygdala is involved in aggression and fear, the hypothalamus is involved in sexual arousal, and the nucleus accumbens, the brain's pleasure centre, is involved in reward, pleasure, and addiction. Furthermore the limbic system controls a host of different functions, including heart rate and blood pressure, hunger, thirst, the sleep and wake cycle, memory formation, and decision making. The two key parts of the limbic system are the hypothalamus and the pituitary gland, the "master gland" of the body. The limbic system interacts with the body through the endocrine system and the autonomic nervous systems. Finally, there is the cerebrum, the largest part of the forebrain, which is evolutionary the most recent and also the largest part of the brain. While the forebrain of a frog is a mere bump, it balloons into the large structure of the cerebrum in higher animals covering the brain stem and the limbic system like the head of a mushroom. The most outstanding feature of the cerebrum is the cortex, which is about two millimetres thick and, like a walnut, possesses an intricately folded surface. This is a special characteristic of "higher" mammals. The many grooves (sulci) and ridges (gyri) create a large surface area of 1,5 square metres allowing for maximum packing of neurons. The cortex is involved in many high-level functions, such as visual and verbal symbol processing, perceptual awareness, communication, language, understanding, and rational thought.

Divisions of the cortex.

The cerebral cortex evolved in three stages and the resulting parts are called archicortex, paleocortex, and neocortex. The most recent one is the neocortex which occupies the topmost layer of the cortex; it is especially developed in humans. Generally, the cerebral cortex acts as a processor of sensory input information, which it receives via the thalamus. The cortex of each hemisphere can be divided into several different areas which are called lobes. At the rear of each hemisphere, the occipital lobe deals primarily with vision, hence, it is also called the visual cortex. It processes visual information transmitted from the eye and analyses it for movement, orientation, and position. A person can become blind if the occipital lobe is damaged, even while the eyes and optic nerves remain intact.

The temporal lobes, located at the outer sides of the hemispheres near the temples, have a number of different functions. A part of it is responsible for hearing. This part is called the auditory cortex. The auditory cortex sits at the lateral fissure and has the size of a large coin. The adjacent areas are involved in high-level auditory processing, such as language perception. Wernicke's area, which is located at the junction of the temporal and parietal lobe, is mainly responsible for the comprehension of spoken language. Additional temporal lobe functions include behavioural expression, the recognition of faces and scenes, as well as episodic and declarative memory, i.e. the memory and retrieval of events and facts as in textbook learning. Damage to the temporal lobes can cause aphasia, the loss of the ability to form and comprehend language. Damage to the right temporal lobe can result in impaired performance of spatial tasks, for example the ability to draw. If the temporal lobe is electrically stimulated, some persons report being present at two places at the same time. They are conscious of the present moment, as well as of another event stored in memory. For example, they might feel they are at the same time in the kitchen of their home, cooking a meal.

The parietal lobe is a relatively large area located at the back of the hemisphere just above the occipital lobe. Much less is known about this lobe than about the other three lobes. It is involved in touch, pain, and taste sensation, visual and spatial perception, and body orientation. It seems that the parietal lobe is where we put our world together. The parietal lobe integrates visual information and constructs maps and coordinate systems that represent how we see the environment. Another function of the parietal lobes is to combine letters into words, and words into sentences. Damage to the left parietal lobe can lead to Gerstmann's syndrome which includes the confusion of left and right, impairment of with writing (aphasia) and calculation abilities (acalculia), and difficulty with recognising body parts (agnosia). Damage to the right parietal lobe can result in difficulties with spatial perception, such as unilateral neglect, the limited conscious awareness of information coming from one side of the body, and constructional apraxia, the inability to draw or construct simple configurations.

The frontal lobe, just behind the forehead, is the largest of the four cortical lobes. It controls much of the rest of the brain's functions. In particular, it is responsible for the higher functions, such as reasoning, planning, organising, problem solving, selective attention, and personality. The frontal lobe is highly connected to the limbic system, which suggests that it is involved in emotions. Moreover, it plays a key role in memory, language processing, speech production, and movement. Cognitive maturity in adulthood is associated with the maturation of cerebral fibres in the frontal lobe. The frontal lobe contains a great number of dopamine-sensitive neurons, which are linked to pleasure, motivation, attention, problem solving and long-term memory. Broca's area, located at the base of the frontal lobe just above the parietal lobe, is thought to be responsible for the production of speech. Brain damage to this area causes expressive aphasia, the inability to form sentences. If the frontal lobes are damaged, the individual may show symptoms of dementia, such as becoming incapable of planning and executing, incapable of comprehending situations and ideas, unable to focus attention, and being distracted by irrelevant stimuli. Other symptoms include impairment of short-term memory, lack of inhibition, and difficulty in learning new information.

The primary motor cortex is located in the precentral gyrus of the frontal lobe, running from the longitudinal fissure at the top of the brain down to the lateral fissure. It controls movements of specific body parts. Electrical stimulation of certain areas of the motor cortex results in movement of the associated body part. From top to bottom, these are feet, legs, hip, trunk, elbows, hands, and face. The areas are not represented in proportion to the size of these body parts. For instance, the areas for the hand and its individual fingers, as well as the area of the face and its different parts are larger than the areas for other body parts. The primary motor cortex receives feedback from the primary somatosensory cortex to which it is intricately linked. The primary somatosensory cortex, located in the postcentral gyrus behind the primary motor cortex, is the main sensory receptive area for the sense of touch. These two areas wok in conjunction with the secondary motor cortex, located before to the primary motor cortex, which prepares movements and combines series of movements into coordinated sequences. Damage to the primary motor cortex disrupts the ability to move one body part (e.g. one finger) independently of another. It can also reduce the speed and accuracy of movements, but it does not cause paralysis.

Lateralisation and the split brain.

The two hemispheres of the cerebrum look almost identical, but at closer inspection we find significant differences. In 1836, a virtually unknown French country doctor found that all of his brain-damaged patients with speech problems suffered injuries to the left side of the brain. This early finding anticipated modern research of brain lateralisation. Clinical evidence suggests that the two sides of the cerebrum serve different functions. Injuries to the left side usually impairs reading, writing, speaking, calculation, and understanding. Injuries to the right side have less dramatic effects, but tend to affect spatial perception and movement. More extensive research has shown that the left and right hemisphere's involvement in certain functions is disproportionate.

Yet, it would be wrong to speak of compartmentalisation. The hemispheres of the brain work in tandem as a complex whole. In a famous experiment in the 1950s, the American neuropsychologist Roger Sperry separated the corpus callosum, to treat epileptics. The corpus callosum is a strand of approx. 200 million nerve fibres connecting the left and right hemispheres, which the brain uses to transfer signals between the hemispheres. The patients remained largely normal, but each hemisphere worked independently. Human split brain patients seemed to have two independent brains, each with its own abilities, memories, and emotions. Notably, the left hemisphere of split brain patients was capable of speech, whereas the right hemisphere was not.
http://www.thebigview.com/mind/brain.html

The beginnings of the thinking brain

June 28, 2006
Oxford researchers have identified the very first neurons in the human cerebral cortex, the part of the brain that sets us apart from all other animals.

ACS Chem Neuro Free Issue - Peer-reviewed journal on molecular mechanisms in Neuroscience - http://pubs.acs.org/journal/acncdm

Dr Irina Bystron and colleagues from the Department of Physiology, Anatomy and Genetics at the University of Oxford, together with Professor Pasko Rakic, a leading neuroscientist at Yale University, describe for the first time in Nature Neuroscience the very earliest nerve cells in the part of the developing human brain that becomes the cerebral cortex.

The cerebral cortex is largely responsible for human cognition, playing an essential role in perception, memory, thought, language, mental ability, intellect and consciousness. It is also responsible for our voluntary actions. As adults our cerebral cortex accounts for 40 per cent of the brain's weight and is composed of about 20 billion neurons. The new findings show that its first neurons are in place much earlier than previously thought – approximately 31 days after fertilization, when the entire embryo is only about 4 mm long and shaped a bit like a comma, before the development of arms, legs or eyes.

The team used cutting-edge techniques, including technologies that allowed them to study which genes are turned on in individual cells. These methods enabled them to identify the first neurons, which they call `predecessor' cells.

Predecessor cells are unusual in many respects. Unlike normal nerve cells, they do not have fibres connecting to other neurons. They do, however, have very long thick processes, or `tails', one stretching out in front of the cell body, the other trailing behind. Analysis of the skeleton of these cells suggests that they move upwards in the surface of the developing brain and enter the future cortex. Their processes form a vast network, and the researchers speculate that this web of processes might be used to guide the migration and development of later cells. Professor Colin Blakemore, one of the authors on the paper, said: `We suspect that these early cells have a special role in development, setting the scene for and controlling neurons that are generated later, and dying when their job is done.'

Unravelling the early development of the cerebral cortex may help in understanding the many developmental disorders of higher brain function, such as autism, schizophrenia, childhood epilepsy, developmental dyslexia and mental retardation.

It might also provide the key to a question that has puzzled evolutionary biologists, namely how the cerebral hemispheres of our hominid ancestors expanded massively, starting about five million years ago. Despite only a 1 per cent genetic difference between humans and gorillas, the human cerebral cortex is four times larger, and our ability to think, understand and to develop culture is dramatically different. It is possible that understanding the way the cerebral cortex develops, and how its development differs from that of other animals, might help explain what happened to give us such clever brains. The researchers are particularly interested in the fact that predecessor cells have never been described in other animals. `A re-examination of early brain development in other species is urgently needed to determine whether predecessor cells are really unique to the human brain,' said Dr Bystron.

Source: University of Oxford:
http://www.physorg.com/news70725285.html

The Thinking Brain

As you read this, you are using your thinking brain. Your thinking brain is responsible for many functions that we take for granted; language, logic, arithemetic and memory to name a few. The part of the brain that is most associated with these functions is the neocortex of the left part of the brain. A few of these functions also require collaboration with the right brain (see The Artistic Brain). To find out more about the thinking brain, explore the links below.

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How does the human brain create language?
What are functions that use both side of the brain?
How are memories created?

How the human brain works? Why are some people insane in the brain?

Answer:
Cognitive modules
The human brain works by activating thought modules (cognitive modules).

Examples of cognitive modules:

The modules controlling your hands when you ride a bicycle, to stop it crashing by minor left and right turns. The modules which allows a basket-ball player to accurately send the ball into the basket.
The modules which recognized hunger and says that you need food.
The modules which cause you to appreciate a beautiful flower, painting or person.
The modules which cause some humans to be jealous of their partners' friends.
The modules which computes the speeds of other vehicles and tells you if you have time to cross before the other car arrives.
The modules which tell you to look both to the right and to the left before crossing a street.
The modules which cause parents to love and take care of their children.
The sex drive modules.
The fight or flight selection modules.

Learned or inherited

Some of these modules are partly based on genetic inheritance, but also the inherited modules can be modified by learning. All you learn, in your childhood, and as an adult, will add new cognitive modules to your brain. An adult human has millions of cognitive modules. The human species is unique in its capability to develop and modify cognitive modules by learning. Thus, the human species is successful because it is not so much controlled by instinct (genetic modules) and that it can modify or replace genetic modules by learned modules.

Selecting the right cognitive modules

How, then, does the human brain select the right module to apply to a certain issue? This can be explained by an analogy with a piano. A piano has a number of strings, one for each tone. If you let a loudspeaker play a single tone loudly, then the corresponding piano string will begin to vibrate. Other piano strings corresponding to close matches, and to overtones of the played tone, will also start to vibrate, but to a less extent. All the piano strings receive the sound, but only those that match the sound will begin to vibrate. Thus, all piano strings test the sound at the same time.

In a similar way, when meeting a situation, this situation will simultaneously test many cognitive modules in the brain. To test manu modules at the same time is known as "parallel processing" and is something which the brain is much better at than computers. But of all tested modules, only those which fit the situation best, are those which are most closely matched with the situation to be managed. The brain then has a selection mechanism, where the cognitive module which is most strongly activated takes over and is used as a model for how to handle the new situation. Examples of this selection mechanism is when you are feeling pain in different parts of the body at the same time, you are only conscious of the strongest of the pains. In the same way, lots of modules may react to your situation, but only one or two of the strongest will make its way up to the conscious mind.

The human brain contains millions of billions of synaptic connections, in which the cognitive modules are stored. This vast size, and the capability to rapidly find appropriate moduels in this large storage, is central to human intelligence.

Difference between the human brain and computers

Note that this is very different from the way a normal computer functions. Few computers have this facility of activating and matching millions of cognitive modules and selecting the appropriate one in a new situation. Especially the human capability to recognize cognitive modules which are in some way similar, but not identical, to a new situation, is unique for humans. Computers are good at finding identical situations, but not good at finding similar but not identical situations.

Psychic disorders

Personality and psychic disorders can then easily be explained by the same model. Such disorders are simply dysfunctional cognitive models. People who have been involved in an airplane accident, may develop a cognitive module which causes them to shy traveling by air. Such cognitive modules are named "phobias".

A person may have developed cognitive modules which were appropriate to handle relations with some other people, for example close family members. They may then apply such modules to other people, even when they are not appropriate. This is in psychology terminology called transference, and is one of the most common causes of neurosis.

Obsessive Compulsive Disorder (OCD) means that some cognitive modules, for example involved with washing, are stimulated too much.

Most law-abiding people have cognitive modules which stop them from committing crimes. Criminals have different modules, causing criminal behaviour.

Paranoia and paranoic personality disorders are cognitive modules which exaggerate the idea that other people are out to get you.

Sigmund Freud's theory of sublimination said that cognitive modules for some activities, such as sex, may incorrectly be applied in cases where they are not suitable. Freud also introduced the idea of the unconscious, by which is meant cognitive modules, where a person is not aware of the initial cause of these modules, and may then use them inappropriately.

Treatment of psychic disorders

The aim of psychotherapy is the modification or replacement of inappropriate cognitive modules (cognitive-behavioural therapy). Important is also training in how to control inappropriate reactions caused by inappropriate cognitive modules. It is easier to do this if you are aware of your inappropriate cognitive modules, thus, understanding and recognizing these modules is also central to psychotherapy. The psychodynamic school of psychotherapy puts much efforts into recognizing how you learned inappropriate modules as a child, while the gestalt school of psychotherapy puts more effort into understanding how the inappropriate modules work in the present.

Certain psychic disorders, such as schizophrenia, depression and OCD, seem to be related to incorrect triggering and emphasis on certain modules. While psychotherapy can help also for such disorders, medicines which modify these incorrect triggerings are also important in the treatment of such disorders. The best effect is often achieved by a combination of medicines and psychotherapy.

Superstition and prejudices

A problem with the human dependence on use of stored cognitive modules is that when such modules are inappropriate or out of date, they are the cause of superstition, prejudice and unwillingness to accept changes.

There is also a problem in that humans very easily construct new cognitive modules which are inappropriate. To understand the mechanism behind this, the result of a psychological experiment can be used. In this experiment, a machine was constructed which generated a random series o bits, 0 or 1. The bits were generated so that on average, one third was a 0 and two thirds was a 1. A test person was then asked to guess, before the display of the next bit, whether that bit would be 0 or 1. The test person would also get paid, with higher payment the more often he/she guessed right. (More information)

Since the bits were random, there was no chance of really guessing what the next bit would be. The optimal strategy for maximising the score would then to always guess at a 1. This would give a score of 66.7 % right. However, very few of the test persons ended up using this optimal strategy. Most of the test persons developed more or less complex rules for whether the next bit would be a 0 or a 1, giving on average a 55.6 % score, .

What this experiment indicates, is that humans, when confronted with a complex reality, tend to construct complex explanations rather than accept that the reality contains a random element which they cannot predict. In real life, this tendency means that people will often guess at explanations which are incorrect, when confronted with a complex reality. Example of such incorrect deductions are beliefs like "Moslems were guilty of the 9/11 attacks, killing 2819 people, thus all moslems are evil" or "This homeopatic medicine makes me better".

The reason why the human mind works in this way, is probably that in many cases, it is useful to build new or revised cognitive modules to handle new kinds of situations. The tendency to build new or revised cognitive modules is thus in most cases a good strategy, and it may be more useful for a person to sometimes generate false cognitive modules than to not try to find explanations for what happens in life.

Group support

Another very common human tendency is to group other people into different kinds of groups, and then to like and support people who belong to the same group as oneself. This tendency can manifest itself as support for people believed to belong to the same ethnic group, religion, or speaking the same language. Even within a language, there are sublanguages, such as the language used my medical doctors when communicating with each other. A person belonging to such a group, such as a medical doctor, will be more positive to another person capable of using the medical language. This tendency is probably partly genetic, and it may have developed in a human life where people belonged to many small tribes and had a need to support members of their own tribe and be suspicuous of members of other tribes.

Are cognitive modules intelligent?

Note that cognitive modules can be intelligent or dumb, rational or emotional, effective or ineffective, suitable or unsuitable. Psychic illness occurs when a person has some cognitive modules which are inappropriate and which dominate too much.

Some people say that human thinking can be categorized into rational thinking and emotional thinking, with an implicit assumption that rational thinking is in some way better or more effective. However, cognitive modules combine rational and emotional thinking, and many very important and appropriate modules are highly emotional, for example the module which causes people to care for and protect children. A better way of categorizing cognitive modules is as appropriate and inappropriate, rather than as rational and emotional modules.

Copyright: This article may be copied according to the GFDL license. Please reference the original article in any copies made of it. http://web4health.info/en/answers/bio-brain-work.htm

Question: What Is Behaviorism?

Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I'll guarantee to take any one at random and train him to become any type of specialist I might select -- doctor, lawyer, artist, merchant-chief and, yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors.
--John Watson, Behaviorism, 1930

Answer:
Behavioral psychology, also known as behaviorism, is a theory of learning based upon the idea that all behaviors are acquired through conditioning. Conditioning occurs through interaction with the environment. According to behaviorism, behavior can be studied in a systematic and observable manner with no consideration of internal mental states.

There are two major types of conditioning:

Classical conditioning is a technique used in behavioral training in which a naturally occurring stimulus is paired with a response. Next, a previously neutral stimulus is paired with the naturally occurring stimulus. Eventually, the previously neutral stimulus comes to evoke the response without the presence of the naturally occurring stimulus. The two elements are then known as the conditioned stimulus and the conditioned response.

Operant conditioning Operant conditioning (sometimes referred to as instrumental conditioning) is a method of learning that occurs through rewards and punishments for behavior. Through operant conditioning, an association is made between a behavior and a consequence for that behavior.
http://psychology.about.com/od/behavioralpsychology/f/behaviorism.htm

Behaviorist Learning Theory

Behaviorism is an approach to psychology based on the proposition that behavior can be researched scientifically without recourse to inner mental states. It is a form of materialism, denying any independent significance for mind. Its significance for psychological treatment has been profound, making it one of the pillars of pharmacological therapy.

B.F. Skinner
Ivan Pavlov

One of the assumptions of behaviorist thought is that free will is illusory, and that all behavior is determined by the environment either through association or reinforcement.

The behaviorist school of thought ran concurrent with the psychoanalysis movement in psychology in the 20th century. Its main influences were Ivan Pavlov, who investigated classical conditioning, John B. Watson (1878-1958) who rejected introspective methods and sought to restrict psychology to experimental laboratory methods. B.F. Skinner, sought to give ethical grounding to behaviorism, relating it to pragmatism.

Within that broad approach, there are different emphases. Some behaviorists argue simply that the observation of behavior is the best or most convenient way of investigating psychological and mental processes. Others believe that it is in fact the only way of investigating such processes, while still others argue that behavior itself is the only appropriate subject of psychology, and that common psychological terms (belief, goals, etc.) have no referents and/or only refer to behavior. Those taking this point of view sometimes refer to their field of study as behavior analysis or behavioral science rather than psychology.

* Classical: The behaviorism of Watson; the objective study of behavior; no mental life, no internal states; thought is covert speech.
* Methodological: The objective study of third-person behavior; the data of psychology must be inter-subjectively verifiable; no theoretical prescriptions. Has been absorbed into general experimental and cognitive psychology. Two popular subtypes are Neo-: Hullian and post-Hullian, theoretical, group data, not dynamic, physiological, and Purposive: Tolman's behavioristic anticipation of cognitive psychology.
* Radical: Skinnerian behaviorism; includes behavioral approach to `mental life;' not mechanistic; internal states not permitted.
* Teleological: Post-Skinnerian, purposive, close to microeconomics. Theoretical: Post-Skinnerian, accepts internal states (the skin makes a difference); dynamic, but eclectic in choice of theoretical structures, emphasizes parsimony.

J. B. Watson

Early in the 20th century, John B. Watson argued in his book Psychology from the Standpoint of a Behaviorist for the value of a psychology which concerned itself with behavior in and of itself, not as a method of studying consciousness. This was a substantial break from the structuralist psychology of the time, which used the method of introspection and considered the study of behavior valueless. Watson, in contrast, studied the adjustment of organisms to their environments, more specifically the particular stimuli leading organisms to make their responses. Most of Watson's work was comparative, i.e., he studied the behavior of animals. Watson's approach was much influenced by the work of Russian physiologist Ivan Pavlov, who had stumbled upon the phenomenon of classical conditioning (learned reflexes) in his study of the digestive system of the dog, and subsequently investigated the phenomena in detail. Watson's approach emphasized physiology and the role of stimuli in producing conditioned responses - assimilating most or all function to reflex. For this reason, Watson may be described as an S-R (stimulus-response) psychologist.

Methodological behaviorism

Watson's behaviorist manifesto persuaded most academic researchers in experimental psychology of the importance of studying behavior. In the field of comparative psychology in particular, it was consistent with the warning note that had been struck by Lloyd Morgan's canon, against some of the more anthropomorphic work such as that of George Romanes, in which mental states had been freely attributed to animals. It was eagerly seized on by researchers such as Edward L. Thorndike (who had been studying cats' abilities to escape from puzzle boxes). However, most psychologists took up a position that is now called methodological behaviorism: they acknowledged that behavior was either the only or the easiest method of observation in psychology, but held that it could be used to draw conclusions about mental states. Among well-known twentieth-century behaviorists taking this kind of position were Clark L. Hull, who described his position as neo-behaviorism, and Edward C. Tolman, who developed much of what would later become the cognitivist program. Tolman argued that rats constructed cognitive maps of the mazes they learned even in the absence of reward, and that the connection between stimulus and response (S->R) was mediated by a third term - the organism (S->O->R). His approach has been called, among other things, purposive behaviorism.

Methodological behaviorism remains the position of most experimental psychologists today, including the vast majority of those who work in cognitive psychology – so long as behavior is defined as including speech, at least non-introspective speech. With the rise of interest in animal cognition since the 1980s, and the more unorthodox views of Donald Griffin among others, mentalistic language including discussion of consciousness is increasingly used even in discussion of animal psychology, in both comparative psychology and ethology; however this is in no way inconsistent with the position of methodological behaviorism.

Politics

Behaviorism relates to a school of politics that developed in the 50s and 60s in the USA. This school represented a revolt against institutional practices in the study of politics and called for political analysis to be modeled upon the natural sciences. That is to say that only information that could be quantified and tested empirically could be regarded as 'true' and that other normative concepts such as 'liberty' and 'justice' should be rejected as they are not falsifiable. This is a version of what has been called scientific empiricism, the view that all beliefs can, at least in principle, be proved scientifically. Skinner has been roundly criticized for his political/social pronouncements, which many perceive as based on serious philosophical errors. His recommendations thus reflect not science, but his own covert preferences.

Behaviourism has been criticised within politics as it threatens to reduce the discipline of political analysis to little more than the study of voting and the behaviour of legislatures. A virtual obsession with the observation of data, although providing interesting findings in these fields deprives the field of politics of other important viewpoints.

Other criticisms have been leveled at the behaviorist claims to be Value Free. This is impossible (it is argued) because every theory is tainted with an ideological premise that led to its formation in the first place and subsequently the observable facts are studied for a reason. An example of this 'value bias' would be that through this discipline the term 'democracy' has become the competition between elites for election 'a la' the western conception rather than an essentially contested term concerning literally rule by the people (the demos). In this manner behaviourism is inherently biased and reduces the scope of political analysis. Nevertheless it has still managed to introduce a new scientific rigour into political analysis and bequeathed a wealth of new information.

B.F. Skinner and radical behaviorism

B.F. Skinner, who carried out experimental work mainly in comparative psychology from the 1930s to the 1950s, but remained behaviorism's best known theorist and exponent virtually until his death in 1990, developed a distinct kind of behaviorist philosophy, which came to be called radical behaviorism. He also claimed to have found a new version of psychological science, which he called behavior analysis or the experimental analysis of behavior.

Definition

Skinner was influential in defining radical behaviorism, a philosophy codifying the basis of his school of research (named the Experimental Analysis of Behavior, or EAB.) While EAB differs from other approaches to behavioral research on numerous methodological and theoretical points, radical behaviorism departs from methodological behaviorism most notably in accepting treatment of feelings, states of mind and introspection as existent and scientifically treatable. This is done by identifying them as something non-dualistic, and here Skinner takes a divide-and-conquer approach, with some instances being identified with bodily conditions or behavior, and others getting a more extended 'analysis' in terms of behavior. However, radical behaviorism stops short of identifying feelings as causes of behavior. Among other points of difference were a rejection of the reflex as a model of all behavior and a defense of a science of behavior complementary to but independent of physiology.

Experimental and conceptual innovations

This essentially philosophical position gained strength from the success of Skinner's early experimental work with rats and pigeons, summarised in his books The Behavior of Organisms (1938) and Schedules of Reinforcement (1957, with C. B. Ferster). Of particular importance was his concept of the operant response, of which the canonical example was the rat's lever-press. In contrast with the idea of a physiological or reflex response, an operant is a class of structurally distinct but functionally equivalent responses. For example, while a rat might press a lever with its left paw or its right paw or its tail, all of these responses operate on the world in the same way and have a common consequence. Operants are often thought of as species of responses, where the individuals differ but the class coheres in its function--shared consequences with operants and reproductive success with species. This is a clear distinction between Skinner's theory and S-R theory.

Skinner's empirical work expanded on earlier research on trial-and-error learning by researchers such as Thorndike and Guthrie with both conceptual reformulations – Thorndike's notion of a stimulus-response 'association' or 'connection' was abandoned – and methodological ones – the use of the 'free operant', so called because the animal was now permitted to respond at its own rate rather than in a series of trials determined by the experimenter procedures. With this method, Skinner carried out substantial experimental work on the effects of different schedules and rates of reinforcement on the rates of operant responses made by rats and pigeons. He achieved remarkable success in training animals to perform unexpected responses, and to emit large numbers of responses, and to demonstrate many empirical regularities at the purely behavioural level. This lent some credibility to his conceptual analysis.

Relation to language

As Skinner turned from experimental work to concentrate on the philosophical underpinnings of a science of behavior, his attention naturally turned to human language. His book Verbal Behavior (1957) laid out a vocabulary and theory for functional analysis of verbal behavior. This was famously attacked by the linguist Noam Chomsky, who presented arguments for the bankruptcy of Skinner's approach in the domain of language and in general. Skinner did not rebut the review, later saying that it was clear to him that Chomsky had not read his book (though subsequent rebuttals have been provided by Kenneth MacCorquodale and David Palmer, among others). Skinner's supporters claim Chomsky's consideration of the approach was superficial in several respects, but the appropriate subject for a study of language was a major point of disagreement. Chomsky (like many linguists) emphasized the structural properties of behavior, while Skinner emphasized its controlling variables.

What was important for a behaviorist analysis of human behavior was not language acquisition so much as the interaction between language and overt behavior. In an essay republished in his 1969 book Contingencies of Reinforcement, Skinner took the view that humans could construct linguistic stimuli that would then acquire control over their behavior in the same way that external stimuli could. The possibility of such instructional control over behavior meant that contingencies of reinforcement would not always produce the same effects on human behavior as they reliably do in other animals. The focus of a radical behaviorist analysis of human behavior therefore shifted to an attempt to understand the interaction between instructional control and contingency control, and also to understand the behavioral processes that determine what instructions are constructed and what control they acquire over behavior. Important figures in this effort have been A. Charles Catania, C. Fergus Lowe, and Steven C. Hayes.

Molar versus molecular behaviorism

Skinner's view of behavior is most often characterized as a "molecular" view of behavior, that is each behavior can be decomposed in atomistic parts or molecules. This view is inaccurate when one considers his complete description of behavior as delineated in the 1981 article, "Selection by Consequences" and many other works. Skinner claims that a complete account of behavior involves an understanding of selection history at three levels: biology (the natural selection or phylogeny of the animal); behavior (the reinforcement history or ontogeny of the behavioral repertoire of the animal); and for some species, culture (the cultural practices of the social group to which the animal belongs). This whole organism, with all those histories, then interacts with its environment. He often described even his own behavior as a product of his phylogenetic history, his reinforcement history (which includes the learning of cultural practices)interacting with the environment at the moment. Molar behaviorists (e.g. Howard Rachlin) argue that behavior can not be understood by focusing on events in the moment. That is, they argue that a behavior can be understood best in terms of the ultimate cause of history and that molecular behaviorist are committing a fallacy by inventing a ficticious proximal cause for behavior. Molar behaviorists argue that standard molecular constructs such as "associative strength" are such fictitious proximal causes that simply take the place of molar variables such as rate of reinforcement. Thus, a molar behaviorist would define a behavior such as loving someone as a exhibiting a pattern of loving behavior over time, there is no known proximal cause of loving behavior (i.e. love) only a history of behaviors (of which the current behavior might be an example of) that can be summarized as love.

Recent experimental work (see The Journal of the Experimental Analysis of Behavior and Journal of Experimental Psychology: Animal Behavior Processes-- 2004 and later) shows quite clearly that behavior is affected both by molar variables (i.e., average rates of reinforcement) and molecular ones (e.g., time, preceding responses). What is needed is an understanding of the real-time dynamics of operant behavior, which will involve processes at both short and long time scales. http://www.innovativelearning.com/teaching/behaviorism.html

* * * * * * *

Adaoma claims:

Netters:

> I have listed the observations and criticisms from the article that I
> initially posted. Not one of them references religion. It is for this
> reason that I have rejected Lil Joe's wresting of the this thread into
> one of religion.

If Adaoma continues to, well, lie, I see no reason to continue this 'discussion'. I am forced to use the word "lie", because, though at first sight one might regard it as an oversignt on her part, or that she forgot what was written in the article she posted. So, I reposted it, proving in fact that Niose did in fact mention 'religion' in his article. In my post a couple of days ago:

Adaoma wrote:
>
> > Materialism necessarily includes atheism. Humanism does not
> necessarily include atheism. And, it is for this reason that Lil Joe
> brought up religion and author David Niose did not.

To which I responded:

As I said, and Adaoma here agrain proves she has not read, of if read didn't understand, that it was precisely Niose, whom she porport here to be defending against 'materialism' and 'atheism', who in the very opening paragraphs both brought up religion and dismissed it as prejudices, false theology and so on that distort history to 'prove prophesies'.

Niose wrote:

"Moreover, those chained to religious dogma are also likely to interpret all of history as validating the prophecies and holy texts of their theology, giving particular emphasis to people and events that are consistent with such views while being dismissive to opposing critiques and views."

Adaoma needs to re-read the article she posted! Again, here it is: http://groups.yahoo.com/group/laborpartypraxis/message/26543

Adaoma might not like the fact that religion is part of this discussion, but to say it isn't is just not true. It is, not only because, as I showed from his statement quoted by Adaoma, but ommitted from her numerical repost below [what dishonesty!] but the very fact that it is in the polemics of Marx-Engels German Ideology, against Young Hegelians and Feuerbach's humanist version of materialism, from which Niose lifted sentences out of its context. I just put the discussion back into the context of the polemics in which Marx and Engels wrote it.

> > In Section 2., Niose the humanists declares that humans have "brain,
> therefore a mind and a psyche" "Mind and psyche" are not materialist
> terms. This confirms my statement that humanism is not materialism
> contrary to Lil Joe's pretending to be in solidarity with humanism,
> conflicts with it.

This is a false accusation.

I have never expressed any 'solidarity' with 19th century philosophical humanism, concerning what is known to be a homo sapien, but 'solidarity' with the findings of contemporary paleoanthropological and anthropological research and primate studies. I supported Marx and Engels rejection of humanism as mystification and philosophical materialism as contemplative, speculative.

I refer people to the contemporary sciences to learn the empirical world on the basis of the most recent empirical data available, and the discussions of that data. That is the only sources I have suggested, the same as when I suggest to those interested in the scientific information regarding evolutionary biology I suggest courses at contemporary universities in biology and genetics, paleontology and so on, not the reading of Lamarck or even Darwin.

So, it is not true, and Adaoma cannot present anything from where I have written anything about consciousness as other than a property of the brain, common to all animals, based on neurology.

Adaoma learns for the first time from Niose: "Niose the humanists declares that humans have "brain"! Can you believe this? All the zoologists, biologists and neuroscientists who have for the past century studied animals didn't know animals had brains? It remained for Niose to 'declare' it to the world???

Then, instead of presenting empirical data and charts as I have above to show how the brain functions, how thinking occurs as a physical process, memories retained, reflexes operate and so on, rather than provide the same kind of objective evidence to demonstate the existence of a non-physical 'mind and psyche', Niose just writes the word "therefore" as the causal connection of a empirical body (the brain is part of the empirical body!) and what Adaoma believes is a non-physical 'mind and psyche'!

Anyway, I think it is evident that Adaoma hasn't read the references to writings of Diderot, Holbach, Helvetius and others the links to which I provided, otherwise she would not keep repeating the same lie, that is that these materialists never used the 'term' mind or 'psyche'.

I 'therefore' find it useless to continue this discussion with Adaoma, when all she does is throw out 'terms', which she hasn't even bothered to define, and making reverences to books she doesn't even bother to read, 'declaring' them refuted them repeating a sentence from somebody named Niose, only because he is attacking Marx by straw man arguments, butchering quotations he has taken out of their time and context.

What 'materialists' and 'humanists' beleved the mind to be is irrelevant today in any case, other than as an historical philosophical inquiry, because their 18th and 19th century materialist and humanist speculations on the subject were a century prior to even the empirical work of Pavlov and Skinner, and the later discoveries in empirical neuroscience, which is where the experimental scientific investigations of the properties of the brain is being conducted. I posted facts of the brain and of thinking process from the university departments in the above sections.

This is not the case of the materialist conception of history, which is not speculation on the 'mind' of man, but the empirical basis of social individual human behavior.

" The premises from which we begin are not arbitrary ones, not dogmas, but real premises from which abstraction can only be made in the imagination. They are the real individuals, their activity and the material conditions under which they live, both those which they find already existing and those produced by their activity. These premises can thus be verified in a purely empirical way.

"The first premise of all human history is, of course, the existence of living human individuals. Thus the first fact to be established is the physical organisation of these individuals and their consequent relation to the rest of nature. Of course, we cannot here go either into the actual physical nature of man, or into the natural conditions in which man finds himself geological, hydrographical, climatic and so on. The writing of history must always set out from these natural bases and their modification in the course of history through the action of men. ...

"The fact is, therefore, that definite individuals who are productively active in a definite way enter into these definite social and political relations. Empirical observation must in each separate instance bring out empirically, and without any mystification and speculation, the connection of the social and political structure with production. (Marx-Engels: "The Critique of German Ideology" )

"Relics of bygone instruments of labour possess the same importance for the investigation of extinct economic forms of society, as do fossil bones for the determination of extinct species of animals. It is not the articles made, but how they are made, and by what instruments, that enables us to distinguish different economic epochs. Instruments of labour not only supply a standard of the degree of development to which human labour has attained, but they are also indicators of the social conditions under which that labour is carried on." (Marx Capital Vol I)

"Social relations are closely bound up with productive forces. In acquiring new productive forces men change their mode of production; and in changing their mode of production, in changing the way of earning their living, they change all their social relations. The hand-mill gives you society with the feudal lord; the steam-mill, society with the industrial capitalist.

"The same men who establish their social relations in conformity with the material productivity, produce also principles, ideas, and categories, in conformity with their social relations. ...

"Just as the economists are the scientific representatives of the bourgeois class, so the Socialists and Communists are the theoreticians of the proletarian class. So long as the proletariat is not yet sufficiently developed to constitute itself as a class, and consequently so long as the struggle itself of the proletariat with the bourgeoisie has not yet assumed a political character, and the productive forces are not yet sufficiently developed in the bosom of the bourgeoisie itself to enable us to catch a glimpse of the material conditions necessary for the emancipation of the proletariat and for the formation of a new society, these theoreticians are merely utopians who, to meet the wants of the oppressed classes, improvise systems and go in search of a regenerating science. But in the measure that history moves forward, and with it the struggle of the proletariat assumes clearer outlines, they no longer need to seek science in their minds; they have only to take note of what is happening before their eyes and to become its mouthpiece. So long as they look for science and merely make systems, so long as they are at the beginning of the struggle, they see in poverty nothing but poverty, without seeing in it the revolutionary, subversive side, which will overthrow the old society. From this moment, science, which is a product of the historical movement, has associated itself consciously with it, has ceased to be doctrinaire and has become revolutionary."(Marx "The Poverty of Philosophy")

Thus the application of this scientific method and conclusion reached by it is used by contemporary paleoanthropology, arecheology, Marxist aanthropology and socialist economists. When these scientists study the 'human mind', it is not by reading the speculations of 18th century materialists, or even Joseph Dietzgen's "The Nature of Human Brain Work", but the contemporary scientific findings as I have shared above for sake of example, of FACTS.

* * * * *

Re: [laborpartypraxis] Re: FYI:Comments on Marx, Human Exceptionaism and Economic Causation. Adaoma wrote:

Netters:
I have listed the observations and criticisms from the article that I initially posted. Not one of them references religion. It is for this reason that I have rejected Lil Joe's wresting of the this thread into one of religion.

In Section 2., Niose the humanists declares that humans have "brain, therefore a mind and a psyche". "Mind and psyche" are not materialist terms. This confirms my statement that humanism is not materialism contrary to Lil Joe's pretending to be in solidarity with humanism, conflicts with it.

For me, this is not about Marx but about the social conditions of the proleteriat and their ideas, what they think and what they want . I don't think anything trumps that.

Adaoma

In his materialist conception of history Karl Marx saw economic factors as the central, driving force that shaped society. He dismissed as idealistic humbug the notion that political and economic organization are shaped by ideas, instead arguing the reverse, that ideas and consciousness develop from the existing material conditions of a given society.

In his Contribution to the Critique of Political Economy, for example, Marx writes: The mode of production of material life determines the social, political and intellectual life process in general. It is not the consciousness of men that determines their being, but, on the contrary, their social being that determines their consciousness.

1. As an animal species humans are defined by their biological characterizations, and any understanding of the human condition, including its history, starts with an understanding of the biological reality of human existence. This biological reality is not just the physical reality of needing food, water and shelter, but also the biological reality of having a brain, and therefore a mind and psyche, that has developed via natural selection.

2.Marx, to his credit, attempts to incorporate natural humanity into his analysis, but for the most part he does little more than allude to the primitive, underlying biological nature of humans without incorporating a thorough commentary on that nature into his analysis.

3. In fact, any fair assessment would conclude that Marx actually downplays the animal nature of humanity, for when discussing the subject he falls into the common trap of quickly embarking on a discussion of what sets humans apart from other animals. This is what I mean when I refer to the human exceptionalism Marx does not wish to thoroughly consider how humans and other animals are alike, but rather he immediately wants to discuss what is unique about the human animal. Thus, early in his materialist conception of history, we find Marx saying:

4.Men can be distinguished from animals by consciousness, by religion or anything else you like. They themselves begin to distinguish themselves from animals as soon as they begin to produce their means of subsistence, a stop which is conditioned by their physical organization. By producing their means of subsistence men are indirectly producing their actual material life.

5. In short, it seems that we can question whether Marx materialism and his particular naturalistic views on history fully and adequately explain the human animal and its troubled condition.

Adaoma
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I need but to present to the Reader Marx himself to dismiss the straw man suggested by Niose and endorsed by Adaoma, in their attacks on the materialist conception of history as 'human exceptionalism' -i.e. according to them that Marx presented an erroneous theory the one of many 'shortcomings' of which, they assert, by taking a single sentence out of its historical and polemical context, the claim that it is locating 'man' outside the animal kingdom, ostensibly "that reveal shortcomings in his analysis" and thus, it's supposed inability to 'adequately explain the human animal and its troubled condition'.

Of course, Neither Niose nor Adaoma bother to define 'the human animal' or its 'troubled condition'. Niose doesn't even provide empirical standard for what objectively determine 'adiquate'.

Thus, they do not themselves offer to explain what actually is, and contrast to precisely what it is in Marx's scientific writings that according to them Marx's materialist conception of history don't 'adequately explain', supposedly because according to Niose Marx removed homo sapiens from the animal kingdom and didn't write about the brain, mind and psyche.

Having above presented the contemporary findings in biology and zoology I now present the statement by Marx on his method in the Afterward of the First Volume of Capital, an empirical and statistical analysis of the properties and laws of motion of capitalist commodity production by wage labour for the Reader to judge whether or not it confirms to what is now known of the plant and animal kingdoms, primate biology and anthropology, neurology and psychology.

The materialist epistemology for their approach to human social phenomena was systematically developed and explicated intially by Marx and Engels in their critiques of the Young Hegelians Bruno and Edgar Bauer, the Egoism of Max Stirner and the materialist humanism of Feuerbach, in The Critique of German Ideology in 1845. This conception of practical materialism as opposed to speculative or contemplative materialism and humanism was the basis for Capital's explication of the dialectics and dynamics of the contradictions that push development of the productive forces and the proletarian revolution.

I present to the Readers consideration from Marx's actual writing on method in response to then critics in an Afterward in Capital Vol. I:

The learned and unlearned spokesmen of the German bourgeoisie tried at first to kill "Das Kapital" by silence, as they had managed to do with my earlier writings. As soon as they found that these tactics no longer fitted in with the conditions of the time, they wrote, under pretence of criticising my book, prescriptions "for the tranquillisation of the bourgeois mind." But they found in the workers' press — see, e.g., Joseph Dietzgen's articles in the Volksstaat — antagonists stronger than themselves, to whom (down to this very day) they owe a reply. [3]

An excellent Russian translation of "Das Kapital" appeared in the spring of 1872. The edition of 3,000 copies is already nearly exhausted. As early as 1871, N. Sieber, Professor of Political Economy in the University of Kiev, in his work "David Ricardo's Theory of Value and of Capital," referred to my theory of value, of money and of capital, as in its fundamentals a necessary sequel to the teaching of Smith and Ricardo. That which astonishes the Western European in the reading of this excellent work, is the author's consistent and firm grasp of the purely theoretical position.

That the method employed in "Das Kapital" has been little understood, is shown by the various conceptions, contradictory one to another, that have been formed of it.

Thus the Paris Revue Positiviste reproaches me in that, on the one hand, I treat economics metaphysically, and on the other hand — imagine! — confine myself to the mere critical analysis of actual facts, instead of writing receipts [4] (Comtist ones?) for the cook-shops of the future. In answer to the reproach in re metaphysics, Professor Sieber has it:

"In so far as it deals with actual theory, the method of Marx is the deductive method of the whole English school, a school whose failings and virtues are common to the best theoretic economists."

M. Block — "Les Théoriciens du Socialisme en Allemagne. Extrait du Journal des Economistes, Juillet et Août 1872" — makes the discovery that my method is analytic and says: "Par cet ouvrage M. Marx se classe parmi les esprits analytiques les plus eminents." German reviews, of course, shriek out at "Hegelian sophistics." The European Messenger of St. Petersburg in an article dealing exclusively with the method of "Das Kapital" (May number, 1872, pp. 427-436), finds my method of inquiry severely realistic, but my method of presentation, unfortunately, German-dialectical. It says:

"At first sight, if the judgment is based on the external form of the presentation of the subject, Marx is the most ideal of ideal philosophers, always in the German, i.e., the bad sense of the word. But in point of fact he is infinitely more realistic than all his forerunners in the work of economic criticism. He can in no sense be called an idealist."

I cannot answer the writer better than by aid of a few extracts from his own criticism, which may interest some of my readers to whom the Russian original is inaccessible.

After a quotation from the preface to my "Criticism of Political Economy," Berlin, 1859, pp. IV-VII, where I discuss the materialistic basis of my method, the writer goes on:

"The one thing which is of moment to Marx, is to find the law of the phenomena with whose investigation he is concerned; and not only is that law of moment to him, which governs these phenomena, in so far as they have a definite form and mutual connexion within a given historical period. Of still greater moment to him is the law of their variation, of their development, i.e., of their transition from one form into another, from one series of connexions into a different one. This law once discovered, he investigates in detail the effects in which it manifests itself in social life. Consequently, Marx only troubles himself about one thing: to show, by rigid scientific investigation, the necessity of successive determinate orders of social conditions, and to establish, as impartially as possible, the facts that serve him for fundamental starting-points. For this it is quite enough, if he proves, at the same time, both the necessity of the present order of things, and the necessity of another order into which the first must inevitably pass over; and this all the same, whether men believe or do not believe it, whether they are conscious or unconscious of it. Marx treats the social movement as a process of natural history, governed by laws not only independent of human will, consciousness and intelligence, but rather, on the contrary, determining that will, consciousness and intelligence. ... If in the history of civilisation the conscious element plays a part so subordinate, then it is self-evident that a critical inquiry whose subject-matter is civilisation, can, less than anything else, have for its basis any form of, or any result of, consciousness. That is to say, that not the idea, but the material phenomenon alone can serve as its starting-point. Such an inquiry will confine itself to the confrontation and the comparison of a fact, not with ideas, but with another fact. For this inquiry, the one thing of moment is, that both facts be investigated as accurately as possible, and that they actually form, each with respect to the other, different momenta of an evolution; but most important of all is the rigid analysis of the series of successions, of the sequences and concatenations in which the different stages of such an evolution present themselves. But it will be said, the general laws of economic life are one and the same, no matter whether they are applied to the present or the past. This Marx directly denies. According to him, such abstract laws do not exist. On the contrary, in his opinion every historical period has laws of its own. ... As soon as society has outlived a given period of development, and is passing over from one given stage to another, it begins to be subject also to other laws. In a word, economic life offers us a phenomenon analogous to the history of evolution in other branches of biology. The old economists misunderstood the nature of economic laws when they likened them to the laws of physics and chemistry. A more thorough analysis of phenomena shows that social organisms differ among themselves as fundamentally as plants or animals. Nay, one and the same phenomenon falls under quite different laws in consequence of the different structure of those organisms as a whole, of the variations of their individual organs, of the different conditions in which those organs function, &c. Marx, e.g., denies that the law of population is the same at all times and in all places. He asserts, on the contrary, that every stage of development has its own law of population. ... With the varying degree of development of productive power, social conditions and the laws governing them vary too. Whilst Marx sets himself the task of following and explaining from this point of view the economic system established by the sway of capital, he is only formulating, in a strictly scientific manner, the aim that every accurate investigation into economic life must have. The scientific value of such an inquiry lies in the disclosing of the special laws that regulate the origin, existence, development, death of a given social organism and its replacement by another and higher one. And it is this value that, in point of fact, Marx's book has."

Whilst the writer pictures what he takes to be actually my method, in this striking and [as far as concerns my own application of it] generous way, what else is he picturing but the dialectic method?

Of course the method of presentation must differ in form from that of inquiry. The latter has to appropriate the material in detail, to analyse its different forms of development, to trace out their inner connexion. Only after this work is done, can the actual movement be adequately described. If this is done successfully, if the life of the subject-matter is ideally reflected as in a mirror, then it may appear as if we had before us a mere a priori construction.

My dialectic method is not only different from the Hegelian, but is its direct opposite. To Hegel, the life process of the human brain, i.e., the process of thinking, which, under the name of "the Idea," he even transforms into an independent subject, is the demiurgos of the real world, and the real world is only the external, phenomenal form of "the Idea." With me, on the contrary, the ideal is nothing else than the material world reflected by the human mind, and translated into forms of thought.

The mystifying side of Hegelian dialectic I criticised nearly thirty years ago, at a time when it was still the fashion. But just as I was working at the first volume of "Das Kapital," it was the good pleasure of the peevish, arrogant, mediocre Epigonoi [Epigones – Büchner, Dühring and others] who now talk large in cultured Germany, to treat Hegel in same way as the brave Moses Mendelssohn in Lessing's time treated Spinoza, i.e., as a "dead dog." I therefore openly avowed myself the pupil of that mighty thinker, and even here and there, in the chapter on the theory of value, coquetted with the modes of expression peculiar to him. The mystification which dialectic suffers in Hegel's hands, by no means prevents him from being the first to present its general form of working in a comprehensive and conscious manner. With him it is standing on its head. It must be turned right side up again, if you would discover the rational kernel within the mystical shell.

In its mystified form, dialectic became the fashion in Germany, because it seemed to transfigure and to glorify the existing state of things. In its rational form it is a scandal and abomination to bourgeoisdom and its doctrinaire professors, because it includes in its comprehension and affirmative recognition of the existing state of things, at the same time also, the recognition of the negation of that state, of its inevitable breaking up; because it regards every historically developed social form as in fluid movement, and therefore takes into account its transient nature not less than its momentary existence; because it lets nothing impose upon it, and is in its essence critical and revolutionary.

The contradictions inherent in the movement of capitalist society impress themselves upon the practical bourgeois most strikingly in the changes of the periodic cycle, through which modern industry runs, and whose crowning point is the universal crisis. That crisis is once again approaching, although as yet but in its preliminary stage; and by the universality of its theatre and the intensity of its action it will drum dialectics even into the heads of the mushroom-upstarts of the new, holy Prusso-German empire.

Karl Marx
London
January 24, 1873

Lil Joe

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