Excerpt from The Presbyterian Review, 1882, Vol. 3Speaking generally, knowledge is the cognition of entity. Non entity cannot be the subject-matter of human investigation. A sub stance, or real being of some kind, is requisite in order to actual knowledge. An exception to this seems to1 1be found in logic and mathematics. Logic is concerned notwith real objects, but with the laws of thinking, and mathematics is occupied with numbers, proportions, points, lines, and surfaces, which have no objective existence, being neither material nor spiritual substance. But, strictly speaking, logic and mathematics are not knowledge itself, but only the organs or instruments of knowledge. They are only auxiliar to the cognition of real being, and hence are denominated formal and not real sciences.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.