_Common Speech distinguishes them._--It must be admitted, however, that in common use there is a distinction between knowing and judging, the one implying the comparative certainty of the thing known, the other implying some room and ground for doubt, the existence of opinion and belief, rather than of positive knowledge. The word itself, both in its primitive signification, and its derivation, indicating, as it does, the decision by legal tribunal of doubtful cases, favors this usage. That an exercise of judgment is, strictly speaking, involved in all knowledge, is, nevertheless true, since, to know that a thing is thus and thus, and not otherwise, is to distinguish it from other things, and that is to judge. § III.--HISTORICAL SKETCH. _The Realist and Nominalist Controversy._ _The Question at Issue._--No question has been more earnestly and even more bitterly discussed, in the whole history of philosophical inquiry, than the point at issue between the Realist and Nominalist, as to what is the precise object of thought when we form an abstract general conception. When I use the term _man_, for example, is it a mere _name_, and nothing more, or is there a _real existence_ corresponding to that name, or is it neither a mere name on the one hand, nor, on the other, a real existence, but a conception of my own mind, which is the object of thought? These three answers can be made, these three doctrines held, and essentially only these three. Each has been actually maintained with great ability and acuteness. The names by which the three doctrines are respectively designated are, Realism, Nominalism, and Conceptualism. _Early History of Realism._--Of these doctrines, the former, Realism, was the first to develop itself. To say nothing of the ancients, we find traces of it in modern philosophy, as early as the ninth century. Indeed, it would seem to have been the prevalent doctrine, though not clearly and sharply defined; a belief, as Tissot has well expressed it, "spontaneous, blind, and without self-consciousness." John Scotus Erigena, and St. Anselm, Archbishop of Canterbury, both philosophers of note, together with many others of less distinction, in the ninth, tenth, and eleventh centuries, were prominent Realists. The Platonic view may, in fact, be said to have prevailed down to that period. The early fathers of the Christian Church were strongly tinged with Platonism, and the Realistic theory accordingly very naturally engrafted itself upon the philosophy of the middle ages. The logical and the ontological, existence as mere thought of the mind, and existence as reality, were not distinguished by the leading minds of those centuries. The reality of the thought as thought, and the reality of an actual existence, corresponding to that thought, were confounded the one with the other. As the rose of which I conceive has existence apart from my conception, so man, plant, tree, animal, are realities, and not mere conceptions of the mind.