Three years before Reid left New Machar, when he was in his thirty-eighth year, he made his first appearance in print, in a short paper contributed to the Royal Society, which appeared in their _Transactions_ in October 1748. It is called ‘An Essay on Quantity.’ It was occasioned by a book published more than twenty years before, the _Inquiry into the Original of our Ideas of Beauty and Virtue_, by Francis Hutcheson, afterwards the celebrated Professor of Moral Philosophy in Glasgow. In this tract simple and compound ratios are applied, in forms of mathematical reasoning, to solve problems of moral philosophy. It illustrates in some degree the bent of Reid’s thoughts at this time, and his inherited interest in mathematical reasonings. But it also shows bent of thought in another direction, and recognition of other scientific methods than mathematical demonstration, which had been favoured as of universal application by philosophers like Descartes and Spinoza. Reid argued, in the spirit of his master Turnbull, that genuine ethical inquiry is concerned with a class of facts which are under a higher category, and refuse to submit to geometrical measurement. It is a curious circumstance in the evolution of philosophy in Scotland that Reid’s first publication should thus be adverse criticism of Hutcheson, the father of Modern Philosophy in Scotland. It is also curious that this juvenile performance presents another of the parallels between Reid and Kant. For it happened that in the preceding year Kant had made his first appearance, on a question concerned with mathematics, and, like Reid’s, in an argument against conclusions maintained by Leibnitz.