Abstract

In his Essay concerning Human Understanding, John Locke claimed that sensations enter the mind as unmixed simple ideas. Because we don't observe the necessary connections which unite such simple ideas into the complex ideas we have of substances, Locke concluded that such complex ideas must be constructed by our minds rather than given by nature. Since our ideas of substances, and the consequent ideas of essences that are abstracted from them, are not given by nature but constructed out of judgment and opinion, those essences and the species we derive from them are merely nominal and not real. ;Locke did believe, however, that there were real essences, and, in the case of material substances, those real essences amounted to the arrangements and motions of the insensible particles that made up the internal structures of material substances. Such real essences were of course unknown in Locke's day, but many scholars have contended that Locke believed such an ignorance was temporary and would be overcome in time as science developed powerful enough instruments to peer into the microscopic world. The major thesis of this dissertation is that such a position is incorrect, and the consequence of all that Locke says is that the real essences of substances will never be known in spite of whatever instruments are developed. Furthermore, this dissertation also questions whether any real essences are knowable given Locke's epistemology and rejection of the Aristotelian position that real essences are given in experience. ;Lastly, this dissertation focuses on the consequences of Locke's position concerning our ignorance of real essences. In particular it examines the logical consequences of Locke's idea of essence upon the notions of science and human understanding in general