As to this last, perhaps the real answer would be that it both is, and is not. That is, the philosophy of Reid would seem still dualistic in its nature; it certainly implies the mechanical contact of two confronting substances whose independence is vigorously maintained, in opposition to the idealistic system which it superseded; but in reference to Reid we must recollect that his theory of Immediate Perception was also something more. As regards sensation, for example, he says that we do not begin with unrelated sensations, but with judgment--that is, we refer our sensations to a permanent subject, 'I.' Sensations 'suggest' the nature of a mind and the belief in its existence. And this signifies that we have the power of making inferences--how we do not exactly know, but we believe it to be, not by any special reasoning process, but by the 'common-sense' innately born within us. Common-sense is responsible for a good deal more--for the conceptions of existence and of cause, for instance; for Reid acknowledges that sensations alone must fail to account for ideas such as those of extension, space, and motion. This standpoint seems indeed as if it did not differ widely from the Kantian, but at the same time Reid appears to think that it is not an essential that feelings should be perceptively referred to an external object; the first part of the process of perception is carried on without our consciousness--the mental sensation merely follows--and sensation simply supposes a sentient being and a certain manner in which that being is affected, which leaves us much where we were, as far as the subjectivity of our ideas is concerned. He does not hold that all sensation is a percept involving extension and much else--involving, indeed, existence. Following upon Reid, Dugald Stewart obtained a very considerable reputation, and he was living and writing at the time Ferrier was a young man. His main idea would, however, seem to have been to guard his utterances carefully, and enter upon no keen discussions or contentions: when a bold assertion is made, it is always under shelter of some good authority. But his rounded phrases gained him considerable admiration, as such writing often does. He carried--perhaps inadvertently--Reid's views farther than he would probably have held as justifiable. He says we are not, properly speaking, conscious of self or the existence of self, but merely of a sensation or some other quality, which, by a _subsequent suggestion_ of the understanding, leads to a belief in that which exercises the quality. This is the doctrine of Reid put very crudely, and in a manner calculated to bring us back to unrelated sensation in earnest. Stewart adopted a new expression for Reid's 'common-sense,' _i.e._ the 'fundamental laws of belief,' which might be less ambiguous, but never took popular hold as did the first.