Great Ideas of Philosophy

B. Other things can be known to be universally true. The proofs of geometry are an example. This sort ofknowledge, however, must be proven through a series of formal arguments. This is not an instance ofintuitive knowledge, but of what Locke calls demonstrative knowledge.C. The most elementary contents of the mind are sensations. All the facts of the external world presentthemselves to and through our sensory channels. Our knowledge of the natural world and of things thathave real existence is by way of perception.1. In his Essay, Locke rehearses the famous Molyneaux problem—whether a man, born blind and givensight via surgery, would be able to recognize visually what he had long learned how to recognizetactually.2. Locke answers the problem as you might expect. On gaining sight, the person could have noappreciation of objects’ shapes or colors. Elementary sensations must be combined and held togetherin some fashion.D. The elementary sensations that form our perceptions are joined together much as the corpuscular elementsof the physical world are held together by gravity to form more complex structures.1. Locke does not examine the mechanisms in any detail and makes clear that he is content not tospeculate.2. Sensations are held together by an essentially associative process. Events we experience togetherfrequently come to be associated together. Out of these elementary sensations, we are able to form, byan associative process, what Locke refers to as simple ideas.IV. The contents of consciousness, to be understood, must be reduced to their most elementary constituents: baresensations.A. Experiences of objects of sensation are of two kinds: primary and secondary.B. Direct experiences of the physical quality of an object—for example, its shape, its hardness, its weight—are experiences of the primary qualities of the thing.C. Other experiences arise from interaction between the primary quality of the object and the properties of thesensory systems themselves, providing experience of a secondary quality—for example, the color ofthings.V. If all we know we know from experiences associated in the mind, old problems of knowledge are raised.Locke’s Essay nods toward a materialistic theory of mind even if it does not explicitly embrace such a theory.A. Locke distinguishes sharply between two senses of “essence” at the fundamental ontological level.1. We do not know the “real essence” of things, because we have no perceptual power equal to the taskof discovering the essence. But the real essence of material objects is what stimulates and brings aboutexperiences, and on the basis of these experiences, we come to classify things according to properties.2. The classifications are in the form of names we give to things, such as animals, fruits, furniture,wagons. Such designations are what Locke calls the nominal essence, which is based on conventionaland pragmatic considerations.B. All this leaves room for a certain skepticism about our knowledge claims.1. How is it, in a sea of change, that Smith remains himself? Is the “ship of Theseus” the same ship, evenafter each of its planks is replaced over a course of years by a new one?2. Locke regarded our personal identities as the gift of experience. Our memories—present inconsciousness and held together in understanding—constitute our continuing personal identities.VI. It was easy to make fun of Locke’s aggregate picture of persons, and Enlightenment wits would poke fun at thereductionist idea that a man who commits a crime is not the same man who is later tried for it, having by thenaccumulated different experiences. But Locke’s writings further established the authority of experience overintuition, reason, and the like and established it as the source of our knowledge of both the external world andthe internal world—though his Newtonian psychology has non-Hobbesian political outcomes.Recommended Reading:Locke, J. An Essay Concerning Human Understanding. Prometheus Books, 1995.Yolton, J. Thinking Matter. University of Minneapolis Press, 1983.©2004 The Teaching Company Limited Partnership 13