COLLIER, ARTHUR (1680-1732), English philosopher, was born at the rectory of Steeple Langford, Wiltshire, and edu cated at Oxford. In 1704 he was presented to the family living of Langford Magna and held it to his death. His philosophical opinions grew out of a diligent study of Descartes and Male branche. He makes no reference to Locke, and shows no knowl edge of his works. His chief work appeared in 1713, under the title Clavis Universalis, or a New Inquiry after Truth, being a Demonstration of the Non-Existence or Impossibility of an Ex ternal World (printed privately, Edinburgh, 1836, and reprinted in Metaphysical Tracts [1837] edited by Sam. Parr).
His views are grounded on two presuppositions : first, the utter aversion of common sense to any theory of representative per ception; second, the opinion shared with Berkeley, that the dif ference between imagination and sense perception is only one of degree. The former is the basis of the negative part of his argument; the latter supplies him with all the positive account he has to give, and that is meagre enough. The Clavis consists of two parts. After explaining that he will use the term "external world" in the sense of absolute, self-existent, independent matter, he attempts in the first part to prove that the visible world is not external, by showing—first, that the seeming externality of a visible object is no proof of real externality; and second, that a visible object, as such, is not external. The second part of the book is taken up with a number of metaphysical arguments to prove the impossibility of an external world. From the hy pothesis of an external world a series of contradictions are deduced, such as that the world is both finite and infinite, is movable and immovable, etc. ; and finally, Aristotle and various other philosophers are quoted, to show that the external matter they dealt with, as mere potentiality, is just nothing at all. As cause of our sensations and ground of our belief in externality, Collier substituted for an unintelligible material substance an equally unintelligible operation of divine power. In philosophy he is a curiosity, and nothing more.
In theology Collier was an adherent of the High Church party, though his views were by no means orthodox. In the Jacobite Mist's Journal he attacked Bishop Hoadly's defence of sincere errors. His views on the problems of Arianism, and his attempt to reconcile it with orthodox theology, are contained in A Specimen of True Philosophy (173o, reprinted in Metaphysical Tracts, 183 7) and Logology, or a Treatise on the Logos in Seven Sermons on John i. I, 2, 3, 14 (1732, analysed in Metaph. Tracts). These may be compared with Berkeley's Siris.
See Robt. Benson, Memoirs of the Life and Writings of Arthur Collier (1837) ; Sir W. Hamilton, Discussions (1852) ; A. C. Fraser, ed. of Berkeley's Works (1871) ; G. Lyon, "Un Idealiste anglais au XVIIIe siecle," in Rev. philos. (188o) , x. 375.