A new and revolutionary emphasis on the tabula rasa occurred late in the 17th century, when the English empiricist John Locke, in An Essay Concerning Human Understanding (1689), argued for the mind’s initial resemblance to “white paper, void of all characters,” with “all the materials of reason and knowledge” derived from experience. Locke did not believe, however, that the mind is literally blank or empty prior to experience, and almost no other empiricist has taken such an extreme position. Locke himself acknowledged an innate power of “reflection” (awareness of one’s own ideas, sensations, emotions, and so on) as a means of exploiting the materials given by experience as well as a limited realm of a priori (nonexperiential) knowledge, which he nevertheless regarded as “trifling” and essentially empty of content (e.g., “soul is soul” and “every man is an animal”).