All of these separations culminate in one between knowing and doing, theory and practice, between mind as the end and spirit of action and the body as its organ and means. We shall not repeat what has been said about the source of this dualism in the division of society into a class laboring with their muscles for material sustenance and a class which, relieved from economic pressure, devotes itself to the arts of expression and social direction. Nor is it necessary to speak again of the educational evils which spring from the separation. We shall be content to summarize the forces which tend to make the untenability of this conception obvious and to replace it by the idea of continuity. (i) The advance of physiology and the psychology associated with it have shown the connection of mental activity with that of the nervous system. Too often recognition of connection has stopped short at this point; the older dualism of soul and body has been replaced by that of the brain and the rest of the body. But in fact the nervous system is only a specialized mechanism for keeping all bodily activities working together. Instead of being isolated from them, as an organ of knowing from organs of motor response, it is the organ by which they interact responsively with one another. The brain is essentially an organ for effecting the reciprocal adjustment to each other of the stimuli received from the environment and responses directed upon it. Note that the adjusting is reciprocal; the brain not only enables organic activity to be brought to bear upon any object of the environment in response to a sensory stimulation, but this response also determines what the next stimulus will be. See what happens, for example, when a carpenter is at work upon a board, or an etcher upon his plate—or in any case of a consecutive activity. While each motor response is adjusted to the state of affairs indicated through the sense organs, that motor response shapes the next sensory stimulus. Generalizing this illustration, the brain is the machinery for a constant reorganizing of activity so as to maintain its continuity; that is to say, to make such modifications in future action as are required because of what has already been done. The continuity of the work of the carpenter distinguishes it from a routine repetition of identically the same motion, and from a random activity where there is nothing cumulative. What makes it continuous, consecutive, or concentrated is that each earlier act prepares the way for later acts, while these take account of or reckon with the results already attained—the basis of all responsibility. No one who has realized the full force of the facts of the connection of knowing with the nervous system and of the nervous system with the readjusting of activity continuously to meet new conditions, will doubt that knowing has to do with reorganizing activity, instead of being something isolated from all activity, complete on its own account.
(ii) The development of biology clinches this lesson, with its discovery of evolution. For the philosophic significance of the doctrine of evolution lies precisely in its emphasis upon continuity of simpler and more complex organic forms until we reach man. The development of organic forms begins with structures where the adjustment of environment and organism is obvious, and where anything which can be called mind is at a minimum. As activity becomes more complex, coordinating a greater number of factors in space and time, intelligence plays a more and more marked role, for it has a larger span of the future to forecast and plan for. The effect upon the theory of knowing is to displace the notion that it is the activity of a mere onlooker or spectator of the world, the notion which goes with the idea of knowing as something complete in itself. For the doctrine of organic development means that the living creature is a part of the world, sharing its vicissitudes and fortunes, and making itself secure in its precarious dependence only as it intellectually identifies itself with the things about it, and, forecasting the future consequences of what is going on, shapes its own activities accordingly. If the living, experiencing being is an intimate participant in the activities of the world to which it belongs, then knowledge is a mode of participation, valuable in the degree in which it is effective. It cannot be the idle view of an unconcerned spectator.
(iii) The development of the experimental method as the method of getting knowledge and of making sure it is knowledge, and not mere opinion—the method of both discovery and proof—is the remaining great force in bringing about a transformation in the theory of knowledge. The experimental method has two sides. (i) On one hand, it means that we have no right to call anything knowledge except where our activity has actually produced certain physical changes in things, which agree with and confirm the conception entertained. Short of such specific changes, our beliefs are only hypotheses, theories, suggestions, guesses, and are to be entertained tentatively and to be utilized as indications of experiments to be tried. (ii) On the other hand, the experimental method of thinking signifies that thinking is of avail; that it is of avail in just the degree in which the anticipation of future consequences is made on the basis of thorough observation of present conditions. Experimentation, in other words, is not equivalent to blind reacting. Such surplus activity—a surplus with reference to what has been observed and is now anticipated—is indeed an unescapable factor in all our behavior, but it is not experiment save as consequences are noted and are used to make predictions and plans in similar situations in the future. The more the meaning of the
