Human Nature and Conduct by John Dewey — Read

In spite of what has been said, it will be asserted that there are definite, independent, original instincts which manifest themselves in specific acts in a one-to-one correspondence. Fear, it will be said, is a reality, and so is anger, and rivalry, and love of mastery of others, and self-abasement, maternal love, sexual desire, gregariousness and envy, and each has its own appropriate deed as a result. Of course they are realities. So are suction, rusting of metals, thunder and lightning and lighter-than-air flying machines. But science and invention did not get on as long as men indulged in the notion of special forces to account for such phenomena. Men tried that road, and it only led them into learned ignorance. They spoke of nature's abhorrence of a vacuum; of a force of combustion; of intrinsic nisus toward this and that; of heaviness and levity as forces. It turned out that these "forces" were only the phenomena over again, translated from a specific and concrete form (in which they were at least actual) into a generalized form in which they were verbal. They converted a problem into a solution which afforded a simulated satisfaction.

Advance in insight and control came only when the mind turned squarely around. After it had dawned upon inquirers that their alleged causal forces were only names which condensed into a duplicate form a variety of complex occurrences, they set about breaking up phenomena into minute detail and searching for correlations, that is, for elements in other gross phenomena which also varied. Correspondence of variations of elements took the place of large and imposing forces. The psychology of behavior is only beginning to undergo similar treatment. It is probable that the vogue of sensation-psychology was due to the fact that it seemed to promise a similar detailed treatment of personal phenomena. But as yet we tend to regard sex, hunger, fear, and even much more complex active interests as if they were lump forces, like the combustion or gravity of old-fashioned physical science.