Dewey left Michigan in 1894 to become professor of philosophy and chairman of the department of philosophy, psychology, and pedagogy at the University of Chicago. Dewey's achievements there brought him national fame. The increasing dominance of evolutionary biology and psychology in his thinking led him to abandon the Hegelian theory of ideas, which views them as somehow mirroring the rational order of the universe, and to accept instead an instrumentalist theory of knowledge, which conceives of ideas as tools or instruments in the solution of problems encountered in the environment. These same disciplines contributed somewhat later to his rejection of the Hegelian notion of an Absolute Mind manifesting itself as a rationally structured, material universe and as realizing its goals through a dialectic of ideas. Dewey found more acceptable a theory of reality holding that nature, as encountered in scientific and ordinary experience, is the ultimate reality and that man is a product of nature who finds his meaning and goals in life here and now.
Since these doctrines, which were to remain at the centre of all of Dewey's future philosophizing, also furnished the framework in which Dewey's colleagues in the department carried on their research, a distinct school of philosophy was in operation. This was recognized by William James in 1903, when a collection of essays written by Dewey and seven of his associates in the department, Studies in Logical Theory, appeared. James hailed the book enthusiastically and declared that with its publication a new school of philosophy, the Chicago school, had made its appearance.
Dewey's philosophical orientation has been labeled a form of pragmatism, though Dewey himself seemed to favour the term “instrumentalism,” or “experimentalism.” William James's The Principles of Psychology early stimulated Dewey's rethinking of logic and ethics by directing his attention to the practical function of ideas and concepts, but Dewey and the Chicago school of pragmatists went farther than James had gone in that they conceived of ideas as instruments for transforming the uneasiness connected with the experience of having a problem into the satisfaction of some resolution or clarification of it.
Dewey's preferred mode of inquiry was scientific investigation; he thought the experimental methods of modern science provided the most promising approach to social and ethical as well as scientific problems. He rejected the idea of a fixed and immutable moral law derivable from consideration of the essential nature of man, since such a traditional philosophical method denied the potential application and promise of newer empirical and scientific methods.
Dewey developed from these views a philosophical ground for democracy and liberalism. He conceived of democracy not as a mere form of government, but rather as a mode of association which provides the members of a society with the opportunity for maximum experimentation and personal growth. The ideal society, for Dewey, was one that provided the conditions for ever enlarging the experience of all its members.
Dewey's contributions to psychology were also noteworthy. Many of the articles he wrote at that time are now accepted as classics in psychological literature and assure him a secure place in the history of psychology. Most significant is the essay “The Reflex Arc Concept in Psychology,” which is generally taken to mark the beginnings of functional psychology—i.e., one that focuses on the total organism in its endeavours to adjust to the environment.
Educational theory and practice. Dewey's work in philosophy and psychology was largely centred in his major interest, educational reform. In formulating educational criteria and aims, he drew heavily on the insights into learning offered by contemporary psychology as applied to children. He viewed thought and learning as a process of inquiry starting from doubt or uncertainty and spurred by the desire to resolve practical frictions or relieve strain and tension. Education must therefore begin with experience, which has as its aim growth and the achievement of maturity.