In 1788 Mackintosh removed to London, then agitated by the trial of Hastings and the king’s first lapse into insanity. He was much more interested in these and other political events than in his professional prospects; and his attention was specially directed to the events and tendencies which caused or preceded the Revolution in France. In the year of his removal to London his father died, and he succeeded to the family estate, which, being small and burdened, brought very little income; and, as he made no headway in his profession, his financial outlook was not very bright. It was under these circumstances that he wedded his first wife Catherine Stuart. Yet his marriage was a happy event for him. His wife’s prudence was a corrective to his own unpractical temperament, and his efforts in journalism soon became fairly profitable. Mackintosh was soon absorbed in the question of the time; and in April 1791, after long meditation, he published his Vindiciae Gallicae, a reply to Burke’s Reflections on the French Revolution. It was the only worthy answer to Burke that appeared. It placed the author in the front rank of European publicists at the age of twenty-five, and won him the friendship of some of the most distinguished men of the time, including Burke himself. About the same time he became honorary secretary of the association of the Friends of the People. The success of the Vindiciae finally decided him to give up the medical for the legal profession. He was called to the bar in 1795, and gained a considerable reputation there as well as a tolerable practice. During this period his greatest public efforts were his lectures (1799) at Lincoln’s Inn on the law of nature and nations, of which the introductory discourse was published, and his eloquent defence (1803) of Jean Peltier, a French refugee, tried at the instance of the French Government for a libel against the first consul. In 1804 he was created knight, and received the post of recorder at Bombay, where he spent the next seven years of his life. The spoilt child of London society was not at home in Bombay. He did seek to interest himself in India, and in imitation of Sir William Jones founded the Literary Society of Bombay; but the current literature of Europe was far more engrossing than the old Indian life, and the packet with the latest tidings from Europe and the newest development of the Napoleonic drama was infinitely more interesting than either. In spite of his scholarly and historic sympathies, his heart always was with the new era, and he was glad to return to England, where he arrived in 1812. True to his old faith, he courteously declined the offer of Perceval to resume political life under the auspices of the dominant Tory party, though tempting prospects of office in connexion with India were opened up. He entered parliament in the Whig interest as member for Nairn. He sat for that county, and afterwards for Knaresborough, till his death. In London society, and in Paris during his occasional visits, he was a recognized favourite for his genial wisdom and his great conversational power. On Madame de Stael’s visit to London he was the only Englishman capable of representing his country in talk with that phenomenal woman. His parliamentary career was marked by the same wide and candid liberalism as his private life. He opposed the repressive and reactionary measures of the Tory Government, supported and afterwards succeeded Romilly in his efforts for reforming the criminal code, and took a leading part both in Catholic emancipation and in the Reform Bill. But he was too little of a partisan, too widely sympathetic and candid, as well as too elaborate, to be a telling speaker in parliament, and was consequently surpassed by more practical men whose powers were incomparably inferior. From 1818 to 1824 he was professor of law and general politics in the East India Company’s College at Haileybury.

In the midst of the attractions of London society and of his parliamentary avocations Mackintosh felt that the real work of his life was being neglected. His great ambition was to write a history of England. His studies both in English and foreign speculation led him to cherish the design also of making some worthy contribution to philosophy. There is real pathos in the fact that it was not till 1828, when he was sixty-three years of age, and even then only at the instance of Macvey Napier, editor of the Encyclopaedia Britannica, that he set about the first task of his literary ambition. This was the Dissertation on the Progress of Ethical Philosophy, prefixed to the seventh edition of the Encyclopaedia. The dissertation, written mostly in ill-health and in snatches of time taken from his parliamentary engagements, was published in 1831. About the same time he wrote for the Cabinet Cyclopaedia a “History of England from the Earliest Times to the Final Establishment of the Reformation.” His more elaborate History of the Revolution, for which he had made great researches and collections, was not published till after his death. Already a privy councillor, Mackintosh was appointed commissioner for the affairs of India under the Whig administration of 1830. He died in 1832.

Mackintosh was undoubtedly one of the most cultured and catholic-minded men of his time. His studies and sympathies embraced almost every human interest, except pure science. But it was the width of his intellectual sympathies joined to a constitutional indecision and vis inertiae that prevented him from doing more enduring work. Thus it was that his actual achievements came so far short both of his real power and of the promise given in his early efforts. The works of Mackintosh which have the best claim to permanent value are the Vindiciae Gallicae, the Dissertation, and the History of the English Revolution. Of the three the first is the greatest both in ability and historical significance. It is the verdict of a philosophic Liberal on the development of the French Revolution up to the spring of 1791, and is at the same time a sympathetic estimate of its causes, principles, and tendencies. While respectful to his great opponent, he is firm and manly in his assertion of the rights and interests of man so deeply concerned in the Revolution. Its excesses compelled him a few years after to express his entire agreement with the opinions of Burke; but few will now deny that his early judgment was the more correct. The Dissertation is a sketchy and fragmentary work, redeemed by catholic criticism and ingenious suggestion. It was a great undertaking, for which half a lifetime would hardly have been sufficient, attempted at a time when the study of the history of philosophy had hardly been begun. Yet his suggestions as to the formation of conscience are valuable. The History of the Revolution in England in 1688, which is only a posthumous fragment of a long meditated history of England beginning with the Revolution, is written in a style of calm and lofty impartiality. It is wanting in colouring, in movement, in the concrete and picturesque, and could never have been a popular history. It gives the history only of three years (1685-88), breaking off at the point where William of Orange is preparing to intervene in the affairs of England. The account of the early career of the prince is a noble and striking piece of work, showing that, if the author could have resisted the charms of society and applied himself resolutely to historical composition, he might have achieved something really great iu that department.

See the Memoirs of Sir James Mackintosh's Life, edited by his son; also Macaulay’s Essay on Sir J. Mackintosh.