Dugald Stewart, a Scottish metaphysician, born in Edinburgh, Nov. 22, 1753, died there, June 11, 1828. His father was the Rev. Dr. Matthew Stewart (1717-85), professor of mathematics in the university of Edinburgh, and author of several mathematical works. He was educated at the high school and university of his native city, heard the lectures of Reid at Glasgow during one term (1771 - '2), was recalled to Edinburgh to act as his father's substitute in the charge of the mathematical classes, and was formally elected conjoint professor in 1775. For several years he was prominent in the weekly debates of the speculative society, before which he also read essays on philosophical subjects. He was elected professor of moral philosophy in 1785, and lectured in this department during the next 24 years. His aim was always moral and practical more than speculative, to portray ideal perfection and advance the harmonious culture of all the faculties, intellectual, moral, and sensitive, rather than to teach definite solutions of intellectual problems; and his lectures therefore proceeded from psychology to theories of character and manners, life and literature, taste and the arts, politics and natural theology.

The prominence which he assigned to the last subject, as the highest branch of metaphysics, was designed, as he explained, to resist the prevalent skeptical tendencies of the era of the French revolution. From the beginning he gave lectures on the theory of government as a part of the course on moral philosophy, and in 1800 he first delivered a special course on the new science of political economy. He published the first volume of " Elements of the Philosophy of the Human Mind" in 1792. In the following year he published his " Outlines of Moral Philosophy," and read before the royal society an account of the life and writings of Adam Smith, which was printed in the " Transactions," and was followed by his biographies of Dr. Robertson (1796) and Dr. Reid (1802). Nothing else appeared from his pen till 1810, though in this interval he prepared the matter of all his other writings, with a single exception. In 1806 the sinecure office of gazette writer of Scotland was created for him. He accompanied in that year Lord Lauderdale on his mission to Paris. In 1810 he retired, on account of failing health, from active duty as a professor, and published his "Philosophical Essays." He had in the mean time removed to Kinneil house, on the shore of the frith of Forth, 20 m. from Edinburgh, where he passed the remainder of his life.

His later publications are: "Elements of the Philosophy of the Human Mind," vol. ii. (1814), and vol. iii. (1827); a preliminary dissertation to the supplement of the "Encyclopedia Britannica," entitled "A General View of the Progress of Metaphysical, Ethical, and Political Science since the Revival of Letters " (part i., 1815; part ii., 1821); and "The Philosophy of the Active and Moral Powers" (1828), which was completed only a few weeks before his death. In 1822 paralysis deprived him of the power of speech and of the use of his right hand, but by the aid of his daughter as an amanuensis he continued his studies until disabled by a fresh paralytic shock, which soon terminated fatally. - His collected works were edited by Sir William Hamilton (10 vols. 8vo, Edinburgh, 1854-'8; supplement, 1860). His lectures on political economy were first published in this edition. The 10th volume contains a memoir by John Veitch, with selections from his correspondence.