The transformation of nature by human activity is the process of the idealization of the material world. In activity, human beings create and sustain an environment written through with significance; they nurture a world enriched with ideal properties, with value and meaning. This is the world we know. Indeed, only an idealized world can be known, for only such a world may be complemented by a subject able to reproduce it in thought and experience. In Marx's words:

On this view, the subjective and objective are not absolutely exclusive categories, but are unified by their common source in activity, which ever sustains their mutual opposition and interchange.

This, for Ilyenkov, is the essence of Marxism's solution to the problem of the ideal. As we have observed, Ilyenkov believes this solution has radical consequences for our understanding of the mind, leading us to reject the abstract philosophical subject of classical epistemology for a conception of the individual as a socially constituted being (see Chapters 5 and 6).