Behaviorism as a psychological and philoso phical interpretation of man and mind grew naturally out of the concept of behavior in animals. If one may study the activities of the cat or the ape from the outside, and can by ex periments determine the capacities of the ani mal and how it learns, discriminates between stimuli, and then can explain these capacities in terms of instinct and training, it is easy to take the next step in the assertion that the activities of man are also forms of behavior and can be examined and explained in the same way. They, too, may be treated merely as forms of response to definite stimuli. With that the traditional attempt- to understand the lower animals in terms of human characteris tics is reversed, and man's acts are explained in terms of the categories of animal behavior. Man is to be studied as the animal is studied, without any help from the individual under investigation. One discovers what the indi vidual can do under given conditions and from the changes in accomplislunent and the ante cedents of the changes develops laws that may explain them. Behaviorism makes no use of introspection and omits all consideration of con sciousness. Several of its exponents go on to deny that consciousness has any existence.
This attitude toward consciousness is in part due to other tendencies that have been active since the beginning of the century. For several reasons the notion of consciousness has been undergoing transformations during the intervening years. By earlier writers con sciousness was taken for granted as in some way made up of images of the objects thought about, which at the same time were not identical in structure with those things. An image of the object was in consciousness and the sum total of these images constituted consciousness. Charcot, Galton and others observed that the character of the images was not the same for all individuals, that certain individuals thought largely in terms of one or two senses, others used different senses or combinations of senses in the representation of objects. Still Galton assumed that thoughts were these images and that nothing else except perhaps words could constitute the vehicle of thought. Later work ers, primarily Kiilpe and his followers in Ger many and Woodworth in this country, noticed that there were many cases in which the mental content bore no relation to the thought repre sented and that in other instances no appreci able imagery was present during the thinking process. In the more abstract forms of rea soning, in reaching decisions and even in in itiating movements often no imagery may be detected. In consequence the theory developed that imagery was not essential to thinking and therefore that consciousness either might have no existence or be very different from what it had been assumed to be. The °New
Realists° (q.v.) also reached the conclusion from more abstract considerations that there could be no distinction between the objective reality and the mental state and prefer to call the common experience objective rather than subjective. Both tendencies prepared the way for behaviorism.
Behaviorism as a purely negative doctrine requires little space for the statement of its theses. As a method of investigation it makes positive contributions as has been seen, but as a system of metaphysics it asserts merely that consciousness does not exist, that one can be come aware of man only from the outside and that it is useless to speculate what goes on inside because there is nothing there. The highest mental operations can be distinguished from the lowest reflex activities only by the complexity of • the actions that result, the time that elapses between the stimulus and the re sponse, and by the greater number of stimuli that co-operate in determining the former. As a method behaviorism abandons all attempt to make use of introspection, or to take any account of what the observer may note of the circumstances that may precede or accompany his action. It replaces these by more careful observation of the slightest movements. Thought is to be examined, not by studying what the individual says but by interpreting the slight unconscious movements of the human larynx. As a metaphysics behaviorism is but another attempt at a complete materialism, a system that has always fascinated certain types of mechanically minded individuals. It dif fers from materialism largely in that the explanations are less detailed, movements are reduced to reflexes and to instinct rather than immediately to chemical and mechanical forces.
That the behaviorists are not altogether satisfied to eliminate consciousness and leave nothing in. its stead to account for internal awareness is admitted, perhaps unwittingly, in the attempts to identify the sensory excitations from the various muscles of the body with a subjective appreciation of the activities that may be observed from without. The more cognitive processes are in some way related to the °back stroke° from the voluntary muscles, the feel ings and emotions to excitations from the vis ceral and other vital organs. Watson identifies thinlcing with movements of the larnyx, pleas ure and pain with various contractions and relaxations of the sex organs. As neither has any immediate value in the world of behavior, they must have value only for subjective aware ness. Whether consciousness is to be replaced by kinwsthetic processes, a familiar position, or whether it is merely an inconsistency that has been inadvertently admitted to the system can not at present be determined.