Dewey had previously written articles on aesthetics in the 1880s and had further addressed the matter in Democracy and Education (1915). In his major work, Experience and Nature (1925), he laid out the beginnings of a theory of aesthetic experience, and wrote two important essays for Philosophy and Civilization (1931).
Such a change in emphasis does not imply, though, that the individual art object has lost significance; far from it, its primacy is clarified: the object is recognized as the primary site for the dialectical processes of experience, as the unifying occasion for these experiences. Through the expressive object, the artist and the active observer encounter each other, their material and mental environments, and their culture at large.
This is a dramatic expansion of the bounds of aesthetic philosophy, for it demonstrates the connections of art with everyday experience and in so doing reminds us of the highest responsibilities that art and society and the individual have always owed to each other:
To emphasize what is aesthetic about an experience is not, finally, to emphasize what is apolitical or impractical or otherwise marginal about that experience; rather, it is to emphasize in what ways that experience, as aesthetic, is a 'manifestation, a record and celebration of the life of a civilization, a means for promoting its development' and, insofar as that aesthetic experience relates to the kinds of experiences had in general, it is also the 'ultimate judgment upon the quality of a civilization.'
See his Experience and Nature for an extended discussion of 'Experience' in Dewey's philosophy.