Any doctrine reconciling the real, independent, objective nature of the world (realism) with a due appreciation of the mind-dependence of the sensory experiences whereby we know about it (hence, critical). In critical, as opposed to naïve, realism the mind knows the world only by means of a medium or vehicle of perception and thought; the problem is to give an account of the relationship between the medium and what it represents. The position was associated especially with R. W. Sellars (1880–1973), whose Critical Realism (1916) was in part a reaction against the supposed simplistic realism of Russell and Moore. In 1920 a number of philosophers including Lovejoy and Santayana contributed to Essays in Critical Realism, which served as a manifesto of the school.