Section 1. Classification of the Sciences.
[*E.C. Richardson, in a little book on classification, quotes an assertion of Robert H[?] in the Presbytarian Review for 1886. VII [?], to the effect that that Comte plagiarized [?] system from [?] [?] and thus the idea of it came from one Dr Burdin, whom I never heard of.]
Auguste Comte it was, as far as I am informed, who first had the idea of arranging the sciences in a ladder, each leading to the next. From the point of view of logic, at least, this is decidedly the best arrangement; because, in order to prove one thing to be true, if one is to proceed beyond mere perceptual facts, it is necessary to assume the truth of something else, while to attempt to prove this something else by assuming the truth of the former proposition would be to complete a vicious circle. It does not very often happen that that there are two independent ways of proving the same thing; and when this does happen, one of those ways will usual be more satisfac tory or more fundamental than the other. When this is not so, it is to be presumed that time will show that both the general premises, or principles, are cases under one still more gen-
is a good and sufficient reason for believing that the problems of science, when they come to be sufficiently understood, can be arranged in hierarchical order, that is, so that any two problems either depend the one on the other, and not conversely, or both depend upon the so lution of one problem, which does not depend upon both. There is, of course, a large assumption here, namly that there is some one first problem, antecedent to all others. [?] this may be presumed true will be a matter for serious inquiry. Meantime, the assumption may stand as a pro visional hypothesis, taken on probation.
But even granting that scientific problems could be arranged in hierarchical order, it still remains to inquire where in the scale we are to draw the lines between the dif ferent sciences. Before undertaking to answer this question in detail, everybody will agree that we ought to determine what the general character of our divisions is to be; and
nobody will dispute that such determination must depend upon our reflections concerning the nature of classification on the one hand, and concerning the nature of science on the other; nor that the reflec tions concerning classification should come first.
Classification must be a topic to be systematically considered in its proper place in this treatise. But long before we are prepared for such a systematic study of it, we shall have to make many classifications. I will here call attention to such detached truths about it as many can be tolerably well established at the outset and are, at the same time, of such a kind that they may afford us some help in making the classifications that we shall have to make. A classification is usually guided by one of four kinds of considerations, as follows: Firstly, it may be based upon the consideration of the purposes, or govern ing ideas, of the objects classified, and upon the different manners in which these purposes are sought to be attained. Secondly, it may be based upon the genealogy, and history of
the evolution of those objects. Third, it may be based upon the abstract forms,- often numerical,- of essential facts concerning these objects. Fourthly, it may be based upon considerations largely extraneous to the objects themselves; usually upon convenience in searching for any given one. The first kind of classification, to wit, that which is based upon the ideas of the objects classified, is the sort of classification with which Plato and Aristotle dealt. It is elaborated in its application to the animal kingdom in the Essay on Classification of Louis Agassi, a work which appeared at an epoch singularly inauspicious for the general recognition of all its greatness. There is no room for doubt that in case we know what ideas have brought objects into existence, they ought to be classified upon the basis of those ideas; and this is the case with the sciences. A perfectly parallel remark is equally indisputable in regard to the evolutionary