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Hamilton Sir William
Hamilton, Sir William, Bart. (1788-1856), a Scotch philosopher, was the son of Dr. William Hamilton, professor of medicine in the university of Glasgow. He was educated at the grammar school and university of his native town, whence he proceeded to Balliol College, Oxford, in 1807. He was appointed professor of civil history at Edinburgh in 1821, and professor of logic and metaphysics in 1836. Meanwhile he had formed a connection with the Edinburgh Review, in which appeared his essays on Cousin (1829), Logic (1833), and Idealism (1839). His edition of Reid's works was published in 1846, and in 1854 appeared the first volume of his edition of Dugald Stewart, which was never completed. His lectures were published after his death, in 1859-61. His power of acquiring knowledge was extraordinary and his acquaintance with philosophical literature has probably never been approached. But much of his knowledge remained unsystematised and serious inconsistencies have been detected in his doctrine, which was severely handled by J. S. Mill in his Examination of Sir William Hamilton's Philosophy (1865).
Hamilton's metaphysical views were in the main those of the Common Sense school of Reid and Stewart, modified to some extent by the doctrines of Kant. In opposition to the Representative theory of Reid, he brought forward his own doctrine of "Natural Realism," maintaining that our notions of an external world are immediately derived from acts of sensible perception. Beyond these reason cannot go, so that it is impossible to prove the existence of a material world, apart from our own consciousness. All our knowledge is based on the necessity and universality of our elementary feelings and beliefs. Necessity is due either to a power or to an impotency of the mind. Our belief in existence and the intuitions of time and space are examples of the former kind. But other beliefs must be explained by the "Law of the Conditioned." Thus unlimited space and a limit to space are alike impossible conceptions, so that we are compelled to think of each object in space as limited itself, but surrounded by other objects. So, too, with regard to causation - every phenomenon must have a cause, but this cause must be itself conditioned, and to carry on the process from cause to cause would result in an infinite regress of thought. On the law of the conditioned, as applied to causation, Hamilton based our consciousness of the freedom of the will, which he regarded as the sole evidence of the existence of God. While explaining it as a direct act of consciousness, he at the same time follows Kant in making it a postulate of the practical reason.