In the course of our analysis of the intellectual phenomena, we shall have frequent opportunities of remarking the influence, which errors with respect to these mere phenomena of mind must have had, on the contemporary systems of general physics, and on the spirit of the prevailing plans of inquiry. It may be enough to remark at present the influence of one fundamental error, which, as long as it retained its hold of the understanding, must have rendered all its energies ineffectual, by wasting them in the search of objects, which it never could attain, because in truth they had no real existence,--to the neglect of objects that would have produced the very advantage which was sought. I allude to the belief of the schools, in the separate existence, or entity as they technically termed it, of the various orders of universals, and the mode in which they conceived every acquisition of knowledge in reasoning, to take place, by the intervention of certain intelligible forms or species, existing separately in the intellect, as the direct objects of thought,--in the same manner as they ascribed simple perception to the action of species of another order, which they termed sensible species,--the images of things derived indeed from objects without, but when thus derived, existing independently of them. When we amuse ourselves with inquiring into the history of human folly--that most comprehensive of all histories--which includes, at least for many ages, the whole history of philosophy; or rather, to use a word more appropriate than amusement,--when we read with regret the melancholy annals of genius aspiring to be pre-eminently frivolous, and industry labouring to be ignorant, we often discover absurdities of the grossest kind, which almost cease to be absurdities, on account of other absurdities, probably as gross, which accompany them; and this is truly the case, in the grave extravagance of the logic of the schools. The scholastic mode of philosophizing, ridiculous as it now seems, was far from absurd, when taken in connection with the scholastic philosophy. It was indeed the only mode of procedure, which that philosophy could consistently admit. To those who believed that singular objects could afford no real knowledge, _singularium nullam dari scientiam_: and that this was to be obtained only from what they termed _intelligible species_, existing not in external things, but in the intellect itself, it must have seemed as absurd to wander, in quest of knowledge, out of that region in which alone they supposed it to exist, and to seek it among things singular, as it would now, to us, seem hopeless and absurd, to found a system of physical truths on the contemplation and comparison of universals. While this false theory of the mental phenomena prevailed, was it possible, that the phenomena of matter should have been studied on sounder principles of investigation, when any better plan must have