In the very able and interesting article in our last number, by Mr. Freeland, that writer announced the doctrine that 'the social, political, religious, and scientific development of the world proceeds under the operation of two grand antagonistic principles,' which he calls respectively, 'Unity,' and 'Individuality.' 'The first of these,' he says, 'tends to bring about cooeperation, consolidation, convergence, dependence; the second to produce separation, isolation, divergence, and independence. Unity is the principle which tends to order; Individuality to freedom.' We are prepared to admit the existence and operation of these principles as stated. They constitute the active tendencies of society, and they perform in the social world precisely what the antagonistic forces of attraction and repulsion do in the physical. They are the principles of aggregation and organization, as well as of agitation, conflict, and all revolutionary or progressive activity. In a more perfect state of development, they will exhibit themselves as the centripetal and centrifugal forces of a beautiful system arrived at that stage of regulated motion which constitutes a stable equilibrium. But while we admit the universal operation of these two principles, we think Mr. Freeland has made a serious mistake in the application of them,--a mistake which seems to run through his entire essay, and to pervade the whole system of his philosophy. We shall venture upon a brief criticism, solely with the view of eliminating truth. The question, though somewhat abstract in its nature, is to us of the highest interest; and we shall ever be ready to yield our position, when convinced that it is erroneous and untenable. We find what we consider the exceptionable doctrine in the following passage: 'Unity is allied to the affections, which are synthetic in their character; Individuality, to the intellect, which is mainly analytical and disruptive in its tendency. Unity is predominant in religion, which is static in its nature; Individuality to science, which is primarily disturbing. In the distribution of the mental faculties, Unity relates to the moral powers, and Individuality to the intellectual; the former being, as both Mr. Buckle and Professor Draper have shown, more stationary in their character than the latter. As in this paragraph the 'affections' are placed in contrast with the 'intellect,' we suppose that by the former the writer intends to designate the emotions or passions, thus making that most obvious analysis of the mind into halves--the active impulses and moral principles on the one hand, and the perceptive and reflective faculties on the other. There is some little confusion of statement, in afterward contrasting the 'moral powers' with the 'intellectual;' but we imagine that the same general classification is intended, although not quite defined with philosophical accuracy.