  The relations between one's first principles, the perceived aims—and limits—of natural philosophy, and one's religious background came together in eighteenth-century Great Britain to issue in a number of different philosophical stances. Typically these stances are framed as various commitments to Newton and Newtonianism. Hume and MacLaurin believe the mind's operations are to be studied with broadly observational Newtonian methods, though this leads them to forms of local skepticism. Priestley and Hartley apply Newtonianism not only to the operations of the mind but to the mind's substance via materialist commitments. Reid's teacher George Turnbull adopted Newtonianism and was led to Berkeleyan idealism by many of Berkeley's own common-sense commitments. Wanting both the world and knowledge of it in his philosophical system, Reid was at pains to articulate his account of both common sense and Newtonianism. Unlike most British Empiricists, Reid read, understood, and taught Newton's writings. To understand Reid's philosophical method, not to mention his philosophy of science, one must understand core features of Reid's Newtonianism (Callergård, 2010) and, perhaps, how Reid altered Newton's own method (Ducheyne 2006).