Considered to be the leading progressive educator of this century, John Dewey wrote on the great issues in education. In Education and Experience, written late in his career, he tries to find a synthesis of the principles of traditional education and those of progressive education. Two essential components for him are the experience of the learner and critical inquiry. Dewey wrote, "any theory and set of practices is dogmatic which is not based upon critical examination of its own underlying principles."

John Dewey's significance for informal educators lies in a number of areas. First, his belief that education must engage with and enlarge experience has continued to be a significant component in informal education practice. Second, and linked to this, Dewey's exploration of thinking and reflection - and the associated role of educators - has continued to be an inspiration. He criticized educational methods that simply amused and entertained students or were overly vocational. He also advocated education that would fulfill and enrich the current lives of students as well as prepare them for the future. Dewey's theory of education became known as functionalism in that it encouraged mental testing and stressed studies of adaptive behavior.