Thinking—a Result of the Evolution of Living
Matter

p The material basis of life is protein, a complex product of the development of matter. Protein compounds, especially in the form of enzyme systems, play a decisive part in metabolism, the basis of the vital activity of every organism. Associated with metabolism are other features of life: reproduction, irritability, etc. Irritability enables living beings to respond to influences oif the internal and external environment by adaptive reactions. This is an elementary form of reflex activity. In the higher stages of the development of the organic world, this property of irritability, which is characteristic of the simplest organisms, becomes the basis for higher nervous activity, and what is called psychic activity.

p Even in unicellular organisms there is a differentiation of elements particularly sensitive to various external stimuli. With the appearance of multicellular animals, specialisation of the cells of the organism occurs, with the appearance of special groups of cells ( receptors) that are capable of receiving external stimuli and of converting the energy of stimulation into excitation. As the animal organism grows more complex, these cells gradually evolve into the nervous system and its central organ, the brain.

p The nervous system is an organ which by its structures and processes reflects all the diverse energetic and spatial-temporal properties of the external world, at the same time co-ordinating the work of organs within the organism itself.

p In vertebrates, the central nervous system is composed of the spinai cord and the brain with its various divisions. In most fish, the brain is relatively small, with hardly any development of the cerebral hemispheres. In amphibia, the brain is bigger and there are the beginnings of the forcbrain, the basis for the development of the cerebral hemispheres. In reptiles, the brain is still more developed and the surface of the hemispheres for the first time shows nerve cells from which the cortex is formed. In birds, the cerebral hemispheres are still bigger, but the cortex little developed. The hemispheres are much more developed in mammals, owing to the development and complexity of the cortex. The higher mammals have an extensive cortex with many irregular ridges and fissures, and the hemispheres cover all the other parts of the brain.

p The highest development of the brain, and especially of its cortex, is to be found in man. The cerebral cortex constitutes an apparatus 37 in constant interaction with the entire nervous system and is the organ of higher nervous activity, of the highest and most complex forms of connection With the external environment. Ivan Pavlov, the great Russian physiologist, said: "Mental activity is the result of the physiological activity of a definite brain mass.”^^6^^ This is tho conclusion drawn by all modern natural science.

p The excitation of the sensory nerve-endings resulting from external and internal stimuli is transmitted through the centripetal nerves to the appropriate parts of the brain. From there impulses are carried by the centrifugal nerves to various organs of the body, stimulating their activity. What we have is a reflex action of the given organ, and the whole organism, to one or another stimulus.

p For example, when you draw your hand away from something hot, that is a reflex action. It is of the kind that psychologists call unconditioned reflexes. They are innate both in animals and man.

p These unconditioned reflexes (defensive, food, etc.) are the basis for conditioned reflexes, which are formed in the course of individual experience. For instance, a dog secretes saliva when it grabs a piece of meat; that is an unconditioned reflex. But salivation can be caused by the sight or smell of meat, or even by the sight of a person who usually feeds the animal. Analysis of this and similar phenomena enabled Pavlov to prove that if feeding is accompanied by a flash of light or the sound of a bell, a new type of reflex response can be developed—the-dog will secrete saliva on seeing the light or hearing the bell. Pavlov called these conditioned reflexes, because they are produced by combining some conditional stimulus (light, sound, etc.) with an unconditioned stimulus that evokes a reflex action.

p Conditioned reflexes are temporary nerve connections. They arise under definite conditions and last for a longer or shorter period without the aid of unconditioned stimuli. Their importance is due to the fact that they enable organisms to adapt themselves to changed conditions of their environment. It is well known, for in. stance, that many wild animals show no alarm on seeing human beings for the first time. Only when man begins to hunt thorn do they change their behaviour, hiding themselves as soon as they see or sense him. They have acquired a new, conditioned reflex, and a very useful one for them: the sight of a man immediately evokes an unconditioned defensive reflex, the signal for purposive adaptive reaction.

p It has been found that any object or natural phenomenon, if combined with unconditioned reflexes, can serve as a signal for conditioned reflex activity. This system of signals, common to both animals and man, Pavlov called the first signalling system.

p At the same time, Pavlov emphasised the specific character of the higher nervous activity of man as compared with animals, lie showed that speech is a new system of signals characteristic only of man, and one that becomes a source of conditioned reflex activity. 38 This system, peculiar to man, Pavlov called the second signalling system.

p A fundamental aspect of Pavlov’s discovery of signalling activity is that the adaptation. of living beings to impending, i.e., future, events, which had always been the prerogative of idealist psychology, henceforth became an object of materialist scientific investigation.

Pavlov discovered the physiological laws of higher nervous activity in animals and man, and he showed the features common to both and the fundamental difference between them. His work has laid a sound scientific basis for an understanding of human mental activity.

The Role of Labour and Speech in the Development
of Human Thought

p Mental activity in man has its precursor in the rudimentary forms of this activity in animals. But the qualitative differences between them must also be seen. The human mind, human thought, is the highest stage in the development of the mental activity. The labour activity of man as a social being has determined the extremely high level of his mental life, his thinking.

p The great English scientist, Charles Darwin, proved that man and the anthropoid apes have common ancestors. In the distant past, man’s animal ancestors were marked by the high development of their fore limbs. They learned to walk erect and began to use natural objects as tools to procure food and to defend themselves. Subsequently, they proceeded to fashion tools, and this marked the gradual transformation of the animal to the human being. The use of tools enabled man to master such a natural force as fire and made it possible for him to improve and vary his food, which in turn helped to develop his brain.

p The use of tools changed man’s relation to nature. The animal passively adapts itself to nature, making use of what nature itself provides. In contrast, man adapts himself to nature actively—he purposively changes nature, creating for himself conditions of existence that he does not find ready-made. Labour has played a decisive part in the development and perfection of man’s brain; in a certain sense, man and his brain have been created by labour.

p The tremendous progress in man’s adaptation to the conditions of his environment, which took the form of changing the external world, only became possible through an extensive development of the human brain’s capacity to appraise the results of behaviour, of labour activity. A powerful impetus to the development of this capacity was given when the ancestor of modern man made the first tool. In its turn, the capacity of the brain to appreciate the results of the labour process served also as the physiological basis for a rapid improvement of the instruments of labour themselves.

p This more complex interaction of man and nature led to more complex relationships between men themselves. For collective labour, men had to associate with one another, and for this the limited stock of sounds that had sufficed for animals was no longer adequate. In the course of labour activities, the human throat gradually developed and changed. Man learned to pronounce articulate sounds, which gradually developed into words, language. Joint labour would have been impossible without the faculty of speech.

p Without words, concepts of things, and their relation to one another could not have arisen; human thought would have been impossible. The emergence and development of speech, in its turn, influenced the development of the brain.

Thus man’s social labour, and later, in association with it, speech, were the decisive factors influencing the development of the brain, the development of the capacity to think.

Consciousness Is a Property of the Brain

p Consciousness is a product of the activity of the human brain, which is connected with the intricate complex of sensory organs. In essence, consciousness is a reflection of the material world. It is a manifold process that includes various types of mental activity, such as sensation, perception, conception, thought, feeling and will. Without the proper functioning of the brain there can be no normal mental activity. Derangement of this functioning by illness, say, or alcohol, impairs the capacity for sound mental activity. Sleep is a partial, temporary inhibition of the activity of the cerebral cortex as a whole—thinking ceases and consciousness is obscured. Recent achievements in influencing selectively and in any desired direction human mental states and pathological emotions by means of various drugs once again proves the primary character of the material cerebral processes underlying the formation of consciousness.

p But from these correct materialist views it does not follow that thought is a substance secreted by the brain. The nineteenth-century German materialist Karl Vogt defined thought as a special substance secreted by the brain, just as our salivary glands secrete saliva or the liver bile. That was a vulgar conception of the nature of thought. Mental activity, consciousness, thought, is a special property of matter, but not a special kind of matter.

p On the fundamental question of philosophy we counterpose consciousness and matter, spirit and nature. Matter is everything that exists independent and outside of our consciousness, and it is therefore a gross error to regard consciousness as part of matter. Lenin said: "To say that thought is material is to make a false step, a stop towards confusing materialism and idealism.”^^7^^ And indeed, if thought is the same thing as matter, that removes all difference between matter and thinking) it makes them identical.

p The idealist opponents of Marxism persist in ascribing to it the view that consciousness is of a material nature. They do so in order to make it easier to “refute” Marxist philosophical materialism. It is a time-honoured device—first to ascribe some absurdity to your opponent and then to subject it to “annihilating” criticism.

p Actually, this identification of consciousness and matter belongs not to dialectical, but to the vulgar materialism. Marxist materialist philosophy has always combated this view, always drawing a distinction between consciousness—the reflection of the material world—and matter itself.

p But this difference should not be exaggerated, not made into an absolute break. Such a break between consciousness and matter is characteristic of psychophysical parallelism, which maintains that thought, consciousness, are processes taking place parallel to, but independent of, material processes occurring in the brain. Science rejects that standpoint. It proves that human mental activity is only a special aspect of the vital activity of the organism, a special function of the brain.

p Dialectical materialism rejects any break between consciousness and matter. For such a break would, in essence, signify a return to the primitive, ignorant views of early human history, when all the phenomena of life were explained as due to a soul that was supposed to enter the body and control it.

In solving the psychophysical problem, i.e., the problem of relation between man’s mental activity and its organ, the brain (as a material organ, a physical body), one must see both the difference and the connection between them. It is important to bear the difference in mind, because identifying consciousness with matter leads to a sheer absurdity. But neither should consciousness be separated from the brain, for consciousness is a function of the brain, i.e., of matter organised in a special way.