The English philosopher and political theorist John Locke (1632-1704) began the empiricist tradition and thus initiated the greatest age of British philosophy. He attempted to center philosophy on an analysis of the extent and capabilities of the human mind.

John Locke was born on Aug. 29, 1632, in Wrington, in Somerset, where his mother's family resided. She died during his infancy, and Locke was raised by his father, who was an attorney in the small town of Pensford near Bristol. John was tutored at home because of his always delicate health and the outbreak of civil war in 1642. When he was 14, he entered Westminster School, where he remained for 6 years. He then went to Christ Church, Oxford. In 1658 he was elected a senior student at his college. In this capacity he taught Greek and moral philosophy. Under conditions at the time he would have had to be ordained to retain his fellowship. Instead he changed to another faculty, medicine, and eventually received a license to practice. During the same period Locke made the acquaintance of Robert Boyle, the distinguished scientist and one of the founders of the Royal Society, and, under Boyle's direction, took up study of natural science. Finally, in 1668, Locke was made a fellow of the Royal Society.

In 1665 Locke traveled to the Continent as secretary to the English ambassador to the Brandenburg court. Upon his return to England he chanced to medically attend Lord Ashley, 1st Earl of Shaftesbury, and later lord chancellor of England. Their friendship and lifelong association drew Locke into political affairs. He attended Shaftesbury as physician and adviser, and in this latter capacity Locke drafted The Fundamental Constitutions of Carolina and served as secretary to the Board of Trade. In 1676 Locke went to France for his health. An inheritance from his father made him financially independent, and he remained in Montpellier for 3 years.

Locke rejoined Shaftesbury's service, and when the latter fled to Holland, the philosopher followed. He remained in exile from 1683 to 1689, and during these years he was deprived of his studentship by express order of Charles III. Most of his important writings were composed during this period. After the Glorious Revolution of 1689 Locke returned to England and later served with distinction as a commissioner of trade until 1700. He spent his retirement at Oates in Essex as the guest of the Mashams. Lady Masham was the daughter of Ralph Cudworth, the philosopher. Locke died there on Oct. 28, 1704.

Major Works

Locke, by virtue of his temperament and mode of existence, was a man of great circumspection. None of his major writings was published until he was nearly 60. In 1690 he brought out his major works: Two Treatises and the Essay Concerning Human Understanding. But the four books of the Essay were the culmination of 20 years of intellectual labor. He relates that, together with a few friends, probably in 1670, a discussion arose concerning the basis of morality and religion. The conclusion was that they were unable to resolve the question until an investigation had been made to see "what objects our understandings were or were not fitted to deal with." Thus the aim of this work is "to inquire into the origin, certainty, and extent of human knowledge, together with the grounds of belief, opinion, and assent."

The procedure employed is what he called the "historical, plain method," which consists of observations derived from external sensations and the internal processes of reflection or introspection. This psychological definition of experience as sensation and reflection shifted the focus of philosophy from an analysis of reality to an exploration of the mind. The new perspective was Locke's major contribution, and it dominated European thought for at least 2 centuries. But if knowledge consists entirely of experience, then the objects of cognition are ideas. The term "idea" was ambiguously defined by Locke as "whatsoever is the object of the understanding when a man thinks." This broad use means that sensations, memories, imaginings, and feelings as well as concepts are ideas insofar as they are mental. The danger of Locke's epistemology is the inherent skepticism contained in a technique which describes what is "in" the mind. For if everything is an idea, then it is difficult to distinguish between true and false, real and imaginary, impressed sensations and expressed concepts. Thus Locke, and the subsequent history of philosophy, had to wrestle with the dilemma that a psychological description of the origin of ideas seriously undermines the extent of their objective validity.

Nonetheless the intention of the Essay was positive in that Locke wished to establish the dependence of all human knowledge upon everyday experience or sensation. The alternative theory of innate ideas is vigorously attacked. Although it is not historically certain whether anyone seriously maintained such a doctrine, Locke's general criticism lends indirect support to an experiential view of knowledge. Innatism can be understood in a naive way to mean that there are ideas of which we are fully conscious at birth or which are universally acknowledged, so that the mind possesses a disposition to think in terms of certain ideas. The first position is refuted by observation of children, and the second by the fact that there are no acknowledged universal ideas to which everyone agrees. The sophisticated version falls into contradiction by maintaining that we are conscious of an unconscious disposition.

Theory of Knowledge

Having refuted the a priori, or nonexperiential, account of knowledge, Locke devotes the first two books of the Essay to developing a deceptively simple empirical theory of knowledge. Knowing originates in external and internal sources of sensation and reflection. The objects or ideas present to consciousness are divided into simple and complex. Simple ideas are primitive sense data, which the mind passively receives and cannot alter, delivered by one sense (seeing blue), by several senses (eating an orange as a synthesis of taste, touch, and smell), by reflection (hunger), or by a combination of sensation and reflection (pleasure and pain). The objective orientation of simple ideas follows from the fact that we cannot add or subtract from their appearance or conception in the mind. In relation to simple ideas, at least, the mind is passive, a "blank" or "white" tablet upon which sensations are impressed. Complex ideas are formed by actively combining, comparing, or abstracting simple ideas to yield "modes, substances, and relations." Modes are class concepts or ideas that do not exist independently, such as beauty. Substance is a complex idea of the unity of substrate of the simple qualities we perceive. And relations are the powers in objects capable of causing minds to make comparisons, for example, identity and cause and effect. The difficulty is that complex ideas do not relate to perceivable existents, but hopefully, complex ideas do express elements or characteristics of the real world.

Locke is faced with an acute dilemma. If the immediate object of knowledge is an idea, then man possesses only a derivative knowledge of the physical world. To know the real world adequately requires a complex idea which expresses the relation between the qualities that we perceive subjectively and the unperceived existent. The substance which unites the common perceived qualities of figure, bulk, and color into this one existing brown table is, in Locke's terms, an "I don't know what." His honesty almost brought Locke to a modern relational definition of substance instead of the traditional notion of a thing characterized by its properties. But the conclusion drawn in the Essay is that knowledge is relational; that is, it consists in the perception "of the agreement or disagreement among ideas." For if Locke had argued that knowledge expresses an adequation between the complex idea in the mind and the real object, then man would have the power to go beyond ideas to the object itself. But this is impossible, since every object is, by definition, an idea, and thus ironically, experiential knowledge is not about real objects but only about the perceived relations of ideas.

The third book of the Essay deals with words, and it is a pioneer contribution to the philosophy of language. Locke is a consistent nominalist in that for him language is an arbitrary convention and words are things which "stand for nothing but the ideas in the mind of the man that has them." Each man's understanding can be confirmed by other minds insofar as they share the same linguistic conventions, although one of the singular abuses of language results from the fact that we learn names or words before understanding their use.

The purpose of Locke's analysis is to account for generalization, abstraction, and universals in terms of language. Generalizations are the result of drawing, or abstracting, what is common to many. In this sense, generalizations and universals are inventions of the mind which concern only signs. But they have a foundation in the similitude of things. And those class concepts which have a fixed meaning and definition can be understood as essences, but they are only nominal and not real. The difference between our knowledge and reality is like that between seeing the exterior of Big Ben and understanding how the clock works.

The final section of the Essay deals with the extent, types, and divisions of knowledge. This work seems to have been written earlier than the others, and many of its conclusions are qualified by preceding material. The agreement or disagreement of ideas, which constitutes knowledge, consists of identity and diversity, perceived relations, coexistence or real existence known by way of intuition, and demonstration or sensation of a given existent.

In this view the actual extent of man's knowledge is less than his ideas because he does not know the real connections between simple ideas, or primary and secondary qualities. Also, an intuitive knowledge of existence is limited to the self, and the only demonstrable existence is that of God as an eternal, omnipotent being. With the exception of the self and God, all knowledge of existing things is dependent upon sensation, whose cognitive status is "a little bit better than probability." The poverty of real knowledge is compensated to some extent by human judgment, which presumes things to be true without actually perceiving the connections. And, according to Locke's commonsense attitude, the severe restrictions placed upon knowledge merely reflect that man's mental capacity is suitable for his nature and condition.

Further Reading

• The best modern editions of Locke are An Essay concerning Human Understanding (2 vols., 1961; rev. ed. 1965), edited by John W. Yolton, and Two Treatises of Government (1960), edited by Peter Laslett. There are various editions of Some Thoughts concerning Education, A Letter concerning Toleration, and The Reasonableness of Christianity. Maurice Cranston, John Locke: A Biography (1957), is the best study. Excellent studies of his philosophy include James Gibson, Locke's Theory of Knowledge and Its Historical Relations (1917), Richard I. Aaron, John Locke (1937; 2d ed. 1955), and John W. Yolton, John Locke and the Way of Ideas (1956).
• Other useful studies of Locke and his thought are Willmoore Kendall, John Locke and the Doctrine of Majority Rule (1959); Crawford B. Macpherson, The Political Theory of Possessive Individualism: Hobbes to Locke (1962); James D. Collins, The British Empiricists: Locke, Berkeley, Hume (1967); Charles B. Martin and D. M. Armstrong, eds., Locke and Berkeley: A Collection of Critical Essays (1968); and John W. Yolton, John Locke: Problems and Perspectives: A Collection of New Essays (1969). For general background see George N. Clark, The Seventeenth Century (1929; 2d ed. 1947), and Basil Willey, The Seventeenth-century Background: Studies in the Thought of the Age in Relation to Poetry and Religion (1934).