In the Essay Concerning Human Understanding Locke examines the nature of the human mind and the process by which it knows the world. Repudiating the traditional doctrine of innate ideas, Locke believed that the mind is born blank, a tabula rasa upon which the world describes itself through the experience of the five senses. Knowledge arising from sensation is perfected by reflection, thus enabling humans to arrive at such ideas as space, time, and infinity.
Locke distinguished the primary qualities of things (e.g., solidity, extension, number) from their secondary qualities (e.g., color, sound). These latter qualities he held to be produced by the impact of the world on the sense organs. Behind this curtain of sensation the world itself is colorless and silent. Science is possible, Locke maintained, because the primary world affects the sense organs mechanically, thus producing ideas that faithfully represent reality. The clear, common-sense style of the Essay concealed many unexplored assumptions that the later empiricists George Berkeley and David Hume would contest, but the problems that Locke set forth have occupied philosophy in one way or another ever since.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.