thumb|Bust of Sir William Hamilton, by [[William Brodie (sculptor)|William Brodie, Old College, University of Edinburgh]]
Sir William Hamilton, 9th Baronet FRSE (8 March 1788 – 6 May 1856) was a Scottish philosopher. He is often referred to as William Stirling-Hamilton (of Preston), in reference to his mother, Elizabeth Stirling.
Early life
Hamilton was born in rooms at the University of Glasgow. and in 1807 went as a Snell Exhibitioner to Balliol College, Oxford. He obtained a first class in literis humanioribus and took his BA in 1811 (MA 1814). He had intended to enter the medical profession, but soon after leaving Oxford, he gave up this idea, and in 1813, he became a member of the Scottish bar as a qualified advocate.
Hamilton's life continued to be that of a student while gradually forming his philosophic system. Investigation enabled him to make good his claim to represent the ancient family of Hamilton of Preston, and in 1816, he took up its baronetcy, which had been in abeyance since the death of Sir Robert Hamilton of Preston (1650–1701).
Early time as a philosopher
Two visits to Germany in 1817 and 1820 led to William's taking up the study of German and, later on, contemporary German philosophy, which was almost entirely neglected in British universities. In 1820, he was a candidate for the chair of moral philosophy in the University of Edinburgh, which had fallen vacant on the death of Thomas Brown, colleague of Dugald Stewart, and Stewart's consequent resignation; however, he was defeated on political grounds by John Wilson (1785–1854), the "Christopher North" of Blackwood's Magazine. In 1821, he was appointed professor of civil history and delivered several courses of lectures on the history of modern Europe and the history of literature. The salary was £100 a year, derived from a local beer tax, and was discontinued after a time. No pupils were compelled to attend; the class dwindled, and Hamilton gave it up when the salary ceased. In January 1827, his mother, to whom he had been devoted, died. In March 1828, he married his cousin, Janet Marshall.
Around this time, he moved to live in a recently built townhouse at 11 Manor Place, in Edinburgh's west end.
Publications
thumb|left|William Hamilton started his literary career in 1829 with the essay "Philosophy of the Unconditioned".
In 1829, his career of authorship began with the appearance of the well-known essay on the "Philosophy of the Unconditioned" (a critique of Victor Cousin's Cours de philosophie)–the first of a series of articles he contributed to the Edinburgh Review. He was elected in 1836 to the University of Edinburgh chair of logic and metaphysics, and from this time dates the influence which, during the next 20 years, he exerted over the thought of the younger generation in Scotland. Much about the same time, he began the preparation of an annotated edition of Thomas Reid's works, intending to annex a number of dissertations to it. However, before this design had been carried out, he was struck, in 1844, with paralysis of the right side which seriously crippled his bodily powers, though it left his mind unimpaired.
The edition of Reid appeared in 1846, but with only seven of the intended dissertations, one unfinished. At his death, he had still not completed the work; notes on the subjects to be discussed were found among his manuscripts. Considerably earlier, he had formed his logic theory, the leading principles indicated in the prospectus of "an essay on a new analytic of logical forms" prefixed to his edition of Reid. But the elaboration of the scheme in its details and applications continued during the next few years to occupy much of his leisure. Out of this arose a sharp controversy with Augustus De Morgan. The essay did not appear, but the results of the labour gone through are contained in the appendices to his Lectures on Logic. Hamilton also drew from the works of Wilhelm Esser in his explanation of laws in the language of agency. For instance, he cited Esser's definition of universal law to explain the sense or "quality" of "necessary".
Hamilton also prepared extensive materials for a publication, which he designed based on the personal history, influence, and opinions of Martin Luther. Here he advanced so far as to have planned and partly carried out the arrangement of the work, but it did not go further and remains in manuscript. In 1852–1853, the first and second editions of his Discussions in Philosophy, Literature and Education appeared, a reprint, with large additions, of his contributions to the Edinburgh Review. Soon after, his general health began to fail. Assisted by his devoted wife, he persevered in literary labour, and during 1854–1855, he brought out nine volumes of a new edition of Stewart's works. The only remaining volume was to have contained a memoir of Stewart, but this he did not live to write. Hamilton was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1855. He taught his class for the last time in the winter of 1855–1856. Shortly after the close of the session, he was taken ill and died in Edinburgh.
Death
thumb|300px|The grave of Sir William Hamilton, St John's Church, Princes Street
He died on 6 May 1856 and was buried in St John's Episcopal Churchyard at the east end of Princes Street in Edinburgh. The stone is not in its original location and is used to edge the enclosure at the east end of the church.
He had married Janet, the daughter of Hubert Marshall, and was succeeded by his son Sir William Stirling-Hamilton, 10th Baronet, a general in the British Army.
Place in thought
In 1840, the University of Leyden granted him an honorary Doctor of Divinity (DD), a rarity for persons outside the clergy.