Stewart, DUGALD, philosopher, was born in Edinburgh on the 22d November 1753, and was the son of Matthew Stewart (q.v.). He entered the High School in his eighth year, and remained till his thirteenth. His subsequent course at the university extended from 1765 to 1769. In the departments of study where his own career afterwards lay he was fortunate to find professors of ability and distinction, the moral philosophy chair being occupied by Adam Ferguson. While Stewart gave his highest promise in these subjects he also made great attainments in mathematics and natural philosophy, and likewise in classics. In 1771 he went to study at Glasgow, partly with a view to one of the Snell scholarships at Balliol College, Oxford, and partly to attend the lectures of Dr Reid. It was while there that he wrote an essay on Dreaming, which was his first effort in mental philosophy, and contained the germs of many of his subsequent speculations. He lived in the same house with Archibald Alison, the author of the Essay on Taste, and the two became intimate friends through life. He was at Glasgow only one session. In 1772, in his nineteenth year, he was called upon by his father, whose health was failing, to teach the mathematical classes in the university of Edinburgh; in 1775 he was elected joint-professor, and acted in that capacity till 1785. In 1778 Adam Ferguson was absent from his post on a political mission to America, and Stewart taught the moral philosophy class in addition to his mathematical classes. The lectures that he gave on this occasion were wholly his own, and were delivered from notes, as was his practice in after years. On the resignation of Ferguson in 1785 he was appointed professor of moral philosophy, and continued in the active duties of the class for twenty-five years. His lectures were greatly admired and numerously attended. He went over a wide compass of subjects: psychology, or the science of mind proper, metaphysics, logic, ethics, natural theology, the principles of taste, politics, and last of all, political economy, which, from the year 1800, he treated in a separate course. In 1792 appeared his first volume of the Elements of the Philosophy of the Human Mind, and in 1793 he published his Outlines of Moral Philosophy. He read before the Royal Society of Edinburgh in 1793 his Account of the Life and Writings of Adam Smith; in 1796 the Account of the Life and Writings of Principal Robertson; and in 1802 the Account of the Life and Writings of Dr Reid. In 1805 he took a prominent part in the 'Leslie controversy,' and wrote a pamphlet maintaining Sir John Leslie's claims to the chair of mathematics and defending him from theological aspersions. In 1806, on the accession of the Whig party to power, he received a sinecure office worth £300 a year. The death of his second son in 1809 gave a blow to his health, otherwise indifferent, and he was unable to lecture during part of the following session; Dr Thomas Brown, at his request, acting as his substitute. The following year Brown was appointed conjoint professor, and taught the class till his death in 1820. From 1809 Stewart lived at Kinneil House, near Bo'ness, which the Duke of Hamilton had placed at his service. In 1810 he published his Philosophical Essays; in 1814 the second volume of the Elements; in 1815 the first part, and in 1821 the second part, of the Dissertation on the History of Ethical Philosophy; in 1827 the third volume of the Elements; and in 1828, a few weeks before his death, the Philosophy of the Active and Moral Powers. On the death of Brown Stewart exerted himself to secure the appointment of Sir William Hamilton to the chair, but the influence used with the town-council in behalf of John Wilson ('Christopher North') was overpowering. Stewart resigned his conjoint professorship on the 20th June 1820; he died 11th June 1828.
The philosophy of Stewart was the following up of the reaction commenced by Reid against the sceptical results that Berkeley and Hume drew from the principles of Locke (see SCOTTISH SCHOOL). Hence arose the principles of common sense of Reid, in which Stewart for the most part acquiesced. Stewart also followed and improved upon Reid in the systematic exposition of all the powers of the mind which rendered mental philosophy for the first time a subject of study, independent of metaphysical, logical, and ethical applications; although he also followed it out in all these directions with his usual perspicacity and felicity of exposition. His contributions to the philosophy of taste, in the Philosophical Essays, are among the best parts of his writings. Although Stewart was not one of the most original thinkers in his department, yet, by the force of his teaching and the compass of his writings, he did much to diffuse an interest in the speculations connected with the human mind. Amongst notable men who studied under Stewart were Lords Jeffrey and Cockburn, Sir Walter Scott, Lord Brougham, Francis Horner, Sir James Mackintosh, James Mill, Lord Palmerston, and Earl Russell.
His works (11 vols. 1854-58) were edited by Sir W. Hamilton, whose work was completed and the biography added by Professor Veitch.