other generic branches should first be prosecuted as constituting the necessary preparation for the study of the higher ordinal principles.
And apropos of this purely pedagogic question, let me emphasize another principle which we also owe to Comte. I have called his system a natural system, and I use that term in the same sense here as when, as a botanist, I speak of the natural system of plants. The order is the order of nature and not of man, and the several sciences not only stand naturally in this order but are genetically affiliated upon one another in this order. That is, each of the five great natural groups rests upon the one immediately below it and grows out of it, as it were. From this it necessarily results that this is the true order in which they should be studied, since the study of each furnishes the mind with that proper data for understanding the next higher. The student, therefore, who advances in this order is approaching the goal of his ambition by two distinct routes which converge at the desired stage. He is laying the foundation for the understanding of the more complex sciences by acquainting himself with the simpler ones upon which they successively rest, and he is at the same time mounting upward in the scale of generalization from the specific and generic to the ordinal or higher groups in a systematic classification. The natural arrangement of the great coördinate groups is serial and genetic. The term "hierarchy" applied to it by Comte is inappropriate, since there is no subordination but simply degrees of generality and complexity. There is genetic affiliation without subordination. The more complex and less exact sciences may be regarded as the children of the more simple and exact ones, but between parent and offspring there is no difference of rank. In contrast with this, the other classification, which I have called synoptical, is a true hierarchy, such as was taught to exist among the angels. It will be easier to comprehend if we liken it to the system of ranking that prevails in an army. The two kinds of classification are entirely different in principle, and the last named occurs independently in each of the great serial groups.
