Immanuel Kant's Critique of Pure Reason — trans. F. Max Müller

zealously pursued, that there was more ground for moderating than for encouraging the desire for it. It was something when chemists succeeded in reducing all salts to two genera, namely, acids and alkalies ; but they tried to consider even this distinction as a variety only, or as a different manifestation of one and the same fun- [p. 653] damental element.

Different kinds of earths (the material of stones and even of metals) have been reduced gradually to three, at last to two ; but not content with this, chemists cannot get rid of the idea that there is behind those varieties but one genus, nay, that there may be even a common principle for the earths and the salts.

It might be supposed that this is only an economical trick of reason, for the purpose of saving itself trouble, and a purely hypothetical attempt which, if successful, would impart by that very unity a certain amount of probability to the presupposed principle of explanation.

Such a selfish purpose, however, can easily be distinguished from the idea according to which we all presuppose that this unity of reason agrees with nature, and that in this case reason does not beg but bids, although we may be quite unable, as yet, to determine the limits of that unity.

If there existed among phenomena so great a diversity, not of form, for in this they may be similar, but of contents, that even the sharpest human understanding could not, by a comparison of the one with the other, discover the slightest similarity among them (a case which is quite conceivable), the logical law of genera would [p. 654] have no existence at all, there would be no concept of genus, nor any general concept, nay, no understanding at all, considering that the understanding has to do with concepts only. The logical principle of genera presup526 Transcendental Dialectic poses, therefore, a transcendental one, if it is to be applied to nature, that is, to all objects presented to our senses. According to it, in the manifoldness of a possible experience, some homogeneousness is necessarily supposed (although it many be impossible to determine its degree a priori)^ because without it, no empirical concepts, and consequently no experience, would be possible.

The logical principle of genera, which postulates identity, is balanced by another principle, namely, that of species, which requires manifoldness and diversity in things, in spite of their agreement as belonging to the same genus, and which prescribes to the understanding that it should pay no less attention to the one than to the other. This principle, depending on acute observation or on the faculty of distinction, checks the geueralising flights of fancy, and reason thus exhibits a twofold and conflicting interest, namely, on the one hand, the interest in the extent (generality) of genera, on the other hand, the interest in the cojitents (distinction) of the manifoldness of species. In the former case the understanding thinks more under its concepts, in the latter, more i^i its concepts. This distinction shows itself in the different manner of thought among students [p. 655] of nature, some of them (who are pre-eminently speculative) being almost averse to heterogeneousness, and always intent on the unity of genera ; while others, preeminently empirical, are constantly striving to divide nature into so much variety that one might lose almost all hope of being able to judge its phenomena according to general principles.

This latter tendency of thought is likewise based on a logical principle which aims at the systematical comTranscendental Dialectic 527