of consciousness. It was difficult to carry over such a mechanism as this into the lower animals. That, at least, took the psychologist out of the field of animal experience. Darwin regarded the animal as that out of which human conduct evolves, as well as the human form, and if this is true then it must be that in some sense consciousness evolves.
The resulting approach is from the point of view of conduct itself, and here the principle of parallelism is brought in. What takes place in consciousness runs parallel with what takes place in the central nervous system. It is necessary to study the content of the form as physiological and also as psychological. The center of consciousness, within which is registered that which affects the sensory nerves and out of which springs the conduct due to sensation and memory images, is to be taken out of the physiological mechanism; and yet one must find a parallel in what takes place in the nervous system for what the physiologist had placed in consciousness as such. What I have referred to in the matter of the emotions seemed to present a physiological counterpart for what takes place in consciousness, a field that seemed to belong peculiarly to the mental side of life. Hate, love, anger – these are seemingly states of mind. How could they be stated in physiological terms? The study of the acts themselves from an evolutionary standpoint, and also the study of the changes that take place in the organism itself when it is under the influence of what we call an emotion, present analogues to these emotional states. One could find something there that definitely answered to the emotions.
The further development of this lead occurred in James's theory of the emotions. Because we run away when we are afraid, and strike when we are angry, we can find something in the physiological organism that answers to fear and to anger. It is an attitude in the organism which answers to these emotional states, especially these visceral conditions to which I have referred, and the sudden changes in the circulation which are found associated with emotions. It becomes possible to relate the psychical conditions with physiological ones. The result was that one could make a much more complete statement of the conduct of the individual in physiological terms, could find a parallel for that which is stated in terms of consciousness in the mechanism of the body and in the operation of that mechanism. Such a psychology was called, naturally enough, a physiological psychology. It was a statement in terms of what went on in the organism of the content with which the psychologist had been dealing. What is there in the act of the animal which answers to these different so-called psychological categories? What is there that answers to the sensations, to the motor responses? When these questions were answered physiologically, they, of course, involved mechanisms located inside of the act, for all that takes place in the body is action. It may be delayed action, but there is nothing there that is itself simply a state, a physiological state that could be compared with a static state. We come then to the sensations and undertake to state them in terms of complete reflex action. We deal with the sensation from the standpoint of the stimulus, and when we come to deal with the various emotional states we deal with them in terms of the preparation for action and the act itself as it is going on. That is, it becomes now essential to relate a set of psychical states with the different phases of the act. Parallelism, then, is an attempt to find analogues between action and experienced contents.
The inevitable result of this analysis was to carry psychology from a static to a dynamic form. It was not simply a question of relating what was found in introspection with what is found in the organism; it became a question of relating together those things which were found in introspection in the dynamic way in which the physiological elements were related to the life of the organism. Psychology became in turn associational, motor, functional, and finally behavioristic.
The historical transformation of psychology was a process which took place gradually. Consciousness was something which could not be simply dispensed with. In early psychology there was a crude attempt to account for consciousness as a certain secretion in the brain, but this was only a ridiculous phase of the transformation. Consciousness was something that was there, but it was something that could be brought into closer and closer relationship with what went on in the body. What went on there had a certain definite order. Everything that took place in the body was part of an act. The earlier conception of the central nervous system assumed that one could locate certain faculties of the mind in certain parts of the brain, but a study of the central nervous system did not reveal any such correlation. It became evident that there were nothing but paths in the central nervous system. The cells of the brain were seen to be parts of the nervous paths provided with material for carrying on the system, but nothing was found there to carry on the preservation of an idea as such. There was nothing in the central nervous system which would enable one to locate a tract given over to abstractions. There was a time when the frontal lobe was regarded as the locus of thought-processes – but the frontal lobe also represents nothing but paths. The paths make very complicated conduct possible, they complicate the act enormously through the mechanism of the brain; but they do not set up any structure which functionally answers to ideas. So the study of consciousness from the standpoint of the organism inevitably led men to look at consciousness itself from the point of view of action.
What, for example, is our experience that answers to clenching of the fist? Physiological psychology followed the action out through the nerves that came from the muscles of the arm and hand. The experience of the act would then be the sensation of what was going on; in consciousness as such there is an awareness of what the organ was doing; there is a parallelism between what goes on in the organ and what takes place in consciousness. This parallelism is, of course, not a complete parallelism. There seems to be consciousness corresponding only to the sensory nerves. We are conscious of some things and not conscious of others, and attention seems to play a very great part in determining which is the case. The parallelism which we carry over does not seem to be complete, but one which occurs only at various points. The thing that is interesting here is that it is the organism that now provides the clew for the analysis. Only portions of the response appear in consciousness as such. The organism has assumed the primary place. Experimental psychology started off from what it could get hold of in the physiological system, and then undertook to find out what in consciousness seemed to answer to it. The scientist felt that he had the same assurance that the physiologist had in identifying these facts in the nervous system, and given those facts he could look into consciousness. It was simpler to start off with the neurosis and then register what was found in the psychosis. Thus, the acceptance of some sort of a parallelism between the contents of consciousness and the physiological processes of the central nervous system led to a conception of those contents dynamically, in terms of acts, instead of statically, in terms of states. In this way the contents of consciousness were approached from below (that is, naturalistically) rather than from above (that is, transcendentally), by a study of the physiological processes of the central nervous system to determine what in the mind answers to the activities of the physiological organism.
There was a question as to the directive centers for unified action. We are apt to think of the central nervous system from the point of view of the telephone board, with calls coming in and responses going out. Certain centers come to be conceived as principal centers. If you go back to the base of the brain, to that portion which is the essence of the central nervous system of lower forms, you do find an organization there which controls in its activity other activities; but when you come to conduct in the human form, you fail to find any such system in which there is a single directive center or group of centers. One can see that the various processes which are involved in running away from danger can be processes which are so interrelated with other activities that the control comes in the organization. One sees the tree as a possible place of escape if a bull is after him; and in general, one sees things which will enable the ongoing activity to be carried out. A varying group of centers may be the determining factor in the whole activity of the individual. That is the concept which has also been carried over into the field of growth. Certain parts of the embryo start growing, and control the action of growth until some other process comes into control. In the cortex, that organ which in some sense answers to human intelligence, we fail to find any exclusive and unvarying control, that is, any evidence of it in the structure of the form itself. In some way we can assume that the cortex acts as a whole, but we cannot come back to certain centers and say that this is where the mind is lodged in thinking and in action. There are an indefinite number of cells connected with each other, and their innervation in some sense leads to a unitary action, but what that unity