JOHN LOCKE, one of the most eminent philosophers of modern times, was born at Wrington, near Bristol, on the 29th of August 1632. His tendency was towards experimental philosophy, and he chose medicine for his profession. In 1664, he went to Berlin, as Secretary to the British envoy, but soon returned to his studies at Oxford. In 1666, he made the acquaintance of Lord Ashley, afterward Earl of Shaftsbury, and on his invitation went to live at his house. In 1672, when Shaftsbury became Lord Chancellor, Locke was appointed Secretary of Presentations, a post which he afterwards exchanged for that of Secretary of the Board of Trade. In 1679, he rejoined the Earl of Shaftsbury in England; but in 1682, the Earl fled to Holland, to avoid a prosecution for high treason. Locke bore him company, and shared with him the hostility of the government of James. But in 1688, the year of the revolution, he came back to England in the fleet that conveyed the Princess of Orange. He soon obtained from the new government the situation of Commissioner of Appeals, worth 200 pounds a year. He took a lively interest in the cause of toleration, and in maintaining the principles of the Revolution. In 1690, his Essay on the Understanding was published, and met with a rapid and extensive celebrity; and also a letter on Toleration and his well-know Treatises on Government. In 1695, King William appointed him a Commissioner of Trade and Plantations. In-the same year he published his treatise on the Reasonableness of Christianity, which was written to promote William's favorite scheme of a comprehension of all the Christian sects in one national church. His last years were very much occupied with the study of the Scriptures, on which he wrote several dissertations, which, with his little work entitled On the Conduct of the Understanding, were published after his death. He died October 28th 1704.
Great as were Locke's services to his country, and to the cause of civil and religious liberty, his fame rests on his Essay on the Understanding, which marks an epoch in the history of Philosophy. His purpose was to inquire into the powers of the human understanding, with a view to find out what things it was fitted to grapple with, and where it must fail, so as to make the mind of man "more cautious in things beyond its comprehension, and disposed to stop when it is at the utmost extent of its tether." This purpose led him to that thorough investigation of the human mind, resulting in the most numerous and important contributions ever made by one man to our knowledge on this subject. He institutes a preliminary inquiry in the subject of the First Book, as to the existence of innate ideas, theoretical and practical, on which the philosophical world has been much divided. Locke argues against the existence of these supposed innate conceptions, or intuitions, of the mind with a force and cogency that appears irresistible. Having thus repudiated the instinctive source of our knowledge or ideas, he is bound to show how we come by them in the course of our experience. Our experience being two fold, external and internal, we have two classes of ideas - those of sensation and those of reflection. He has therefore to trace all the recognized conceptions of the mind to one or the other of these sources.
Many of our notions are obviously obtained from experience, as colors, sounds, etc. but some have been disputed, more especially such as Space, Time, Infinity, Power, Substance, Cause, mere Good and Evil; and Locke discusses these at length, by way of tracing them to the same origin. This is the subject of Book Second, entitled "Of Ideas." Book Third is on language considered as an instrument of truth, and contains much valuable material. The Fourth Book is on the nature, limits, and reality of our knowledge, including the nature of demonstrative truth, the existence of a God, the provinces of faith and reason, and the knowledge of error.