men can reason together, they must agree in first principles; and it is impossible to reason with a man who has no principles in common with you." One of the first principles he goes on to list is that "qualities must necessarily be in something that is figured, coloured, hard or soft, that moves or resists. It is not to these qualities, but to that which is the subject of them, that we give the name body. If any man should think fit to deny that these things are qualities, or that they require any subject, I leave him to enjoy his opinion as a man who denies first principles, and is not fit to be reasoned with." Reid also made positive arguments based in phenomenological insight to put forth a novel mixture of direct realism and ordinary language philosophy. In a typical passage in The Intellectual Powers of Man he asserts that when he has a conception of a centaur, the thing he conceives is an animal, and no idea is an animal; therefore, the thing he conceives is not an idea, but a centaur. This point relies both on an account of the subjective experience of conceiving an object and also on an account of what we mean when we use words. Because Reid saw his philosophy as publicly accessible knowledge, available both through introspection and through the proper understanding of how language is used, he saw it as the philosophy of common sense. Exploring sense and language Reid started out with a 'common sense' based on a direct experience of an external reality but then proceeded to explore in two directions—external to the senses, and internal to human language—to account more effectively for the role of rationality. Reid saw language as based on an innate capacity pre-dating human consciousness, and acting as an instrument for that consciousness. (In Reid's terms: it is an 'artificial' instrument based on a 'natural' capacity.) On this view, language becomes a means of examining the original form of human cognition. Reid notes that current human language contains two distinct elements: first, the acoustic element, the sounds; and secondly the meanings—which seem to have nothing to do with the sounds as such. This state of the language, which he calls 'artificial', cannot be the primeval one, which he terms 'natural', wherein sound was not an abstract sign, but a concrete gesture or natural