John Locke’s purpose in An Essay Concerning Human Understanding is to inquire into the origin and extent of human knowledge. His conclusion—that all knowledge is derived from sense experience—became the principal tenet of empiricism, which has dominated Western philosophy ever since. Even George Berkeley, who rejected Locke’s distinction between sense qualities independent of the mind and sense qualities dependent on the mind, produced his idealism in response to Locke’s provocative philosophy and gave it an empirical cast that reflected Western culture’s rejection of innate or transcendental knowledge.
An Essay Concerning Human Understanding is divided into four books: book 1, “Of Innate Notions”; book 2, “Of Ideas”; book 3, “Of Words”; and book 4, “Of Knowledge, Certain and Probable.”
In preparation for his radical claim that all ideas are derived from experience, Locke begins his essay with a careful consideration of the thesis that there are innate ideas. Locke first examines the notion that there are ideas that are a necessary part of human understanding and are, therefore, common to all people. Locke’s attack on this thesis is from two directions. He argues that many of the ideas that are supposed to be innate can be and have been derived naturally from sense experience, that not all people assent to those ideas that are supposed to be innate. Locke maintains that even if reason enables people to discover the truth of certain ideas, those ideas cannot be said to be innate, for reason is needed to discover their truth.
In book 2, “Of Ideas,” Locke considers the origin of such ideas as those expressed by the words “whiteness,” “hardness,” “sweetness,” “thinking,” “motion,” “man,” and the like. The second section states his conclusion: Let us then suppose the mind to be, as we say, white paper void of all characters, without any ideas. How comes it to be furnished? . . . Whence has it all the materials of reason and knowledge? To this I answer, in one word, from experience. . . . Our observation, employed either about external sensible objects, or about the internal operations of our minds perceived and reflected on by ourselves, is that which supplies our understandings with all the materials of knowledge.
The two sources of ideas, according to Locke, are sensation and reflection. By the senses people come to have perceptions of things, thereby acquiring the ideas of yellow, white, or cold, for example. Then, by reflection, by consideration of the mind in operation, people acquire the ideas of thinking, doubting, believing, knowing, willing, and so on.
By sensation people acquire knowledge of external objects; by reflection people acquire knowledge of their own minds. Ideas that are derived from sensation are simple; that is, they present “one uniform appearance,” even though a number of simple ideas may come together in the perception of an external object. The mind dwells on the simple ideas, comparing them to one another, combining them, but never inventing them. By a “simple idea” Locke...
(The entire section is 1282 words.)