John Dewey believed that to understand oneself and others, one must study human nature and the social institutions in which it functions because both forces work to shape the individual. Morality is the interaction between the two. In the preface to Human Nature and Conduct, Dewey says that his book “sets forth a belief that an understanding of habit and of different types of habit is the key to social psychology while the operation of impulse and intelligence gives the key to individualized mental activity. However, they are secondary to habit so that the mind can be understood in the concrete only as a system of beliefs, desires and purposes which are formed in the interaction of biological aptitudes with a social environment.”
Dewey criticizes the morality of the past as based largely on arbitrary rules rather than on a scientific understanding of human beings. The few have given and administered rules that the many have obeyed with reluctance, if at all. Such morality is largely restrictive, concerned with what should not be done. Many people conform, but others circumvent the morality in their practice, while giving lip service to it or by having a theory that avoids it. The Romantic device of the glorification of impulse as opposed to knowledge is such a theory. Those who attempt to live by a morality divorced from an adequate theory of human nature inhabit a world in which the ideal and the real are sharply separated. They must renounce one world or live uneasily in a world split in two.
It is Dewey’s contention that knowledge can solve moral problems and that scientific method holds the best promise of providing knowledge. The moral life operates in an environmental setting that is both natural and social. Human nature is continuous with the rest of nature, and as a result, ethics is allied with physics and biology. Because the activities of one person are continuous with those of others, ethics is allied with such social sciences as sociology, law, and economics. Even the past is not irrelevant. One can study history to understand the present as derived from the past and to help determine the structure of the future.