He had been intended for the medical profession, but soon after leaving Oxford he gave up this idea, and in 1813 became a member of the Scottish bar, as a qualified advocate.

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 to it a number of dissertations.

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 left his mind unimpaired.

[4] Hamilton also prepared extensive materials for a publication which he designed on the personal history, influence and opinions of Martin Luther.

In 1852–1853 appeared the first and second editions of his Discussions in Philosophy, Literature and Education, a reprint, with large additions, of his contributions to the Edinburgh Review.

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.

Its chief practical corollary is the denial of philosophy as a method of attaining absolute knowledge and its relegation to the academic sphere of mental training.

The transition from philosophy to theology, i.e. to the sphere of faith, is presented by Hamilton under the analogous relation between the mind and the body.

He was quite ready to allow that on this view logic cannot be used as a means of discovering or guaranteeing facts, even the most general, and expressly asserted that it has to do, not with the objective validity, but only with the mutual relations, of judgments.

He further held that induction and deduction are correlative processes of formal logic, each resting on the necessities of thought and deriving thence its several laws.

The only logical laws which he recognised were the three axioms of identity, noncontradiction, and excluded middle, which he regarded as severally phases of one general condition of the possibility of existence and, therefore, of thought.

in logic, Hamilton is known chiefly as the inventor of the doctrine of the "quantification of the predicate," i.e. that the judgment "All A is B " should really mean "All A is all B," whereas the ordinary universal proposition should be stated "All A is some B."

With the commentators on the Aristotelian writings, ancient, medieval and modern, he was also familiar; and the scholastic philosophy he studied with care and appreciation at a time when it had hardly yet begun to attract attention in his country.

His wide reading enabled him to trace many a doctrine to the writings of forgotten thinkers; and nothing gave him greater pleasure than to draw forth such from their obscurity, and to give due acknowledgment, even if it chanced to be of the prior possession of a view or argument that he had thought out for himself.

How profoundly his thinking was modified by that of Kant is evident from the tenor of his speculations; nor was this less the case because, on fundamental points, he came to widely different conclusions.

He also may have influenced subsequent philosophy as the inspiration for a critique by John Stuart Mill which resulted in perhaps the clearest statements ever of the idea of matter as the permanent possibility of sensation.

As a teacher, he was zealous and successful, and his writings on university organisation and reform had, at the time of their appearance, a decisive practical effect, and contain much that is of permanent value.