As for the law of specification, Kant expresses it thus: entium varietates non temere esse minuendas. It requires namely, that we should clearly distinguish one from another the different genera collected under one comprehensive conception; likewise that we should not confound the higher and lower species comprised in each genus; that we should be careful not to overleap any, and never to classify inferior species, let alone individuals, immediately under the generic conception: each conception being susceptible of subdivision, and none even coming down to mere intuition. Kant teaches that both laws are transcendental, fundamental principles of our Reason, which postulate conformity of things with them a priori; and Plato, when he tells us that these rules were flung down from the seat of the gods with the Promethean fire, seems to express the same thought in his own way.
§ 2. Application of the Method in the present case.
In spite of the weight of such recommendations, I find that the second of these two laws has been far too rarely applied to a fundamental principle of all knowledge: the Principle of Sufficient Reason. For although this principle has been often and long ago stated in a general way, still sufficient distinction has not been made between its extremely different applications, in each of which it acquires a new meaning; its origin in various mental faculties thus becoming evident. If we compare Kant's philosophy with all preceding systems, we perceive that, precisely in the observation of our mental faculties, many persistent errors have been caused by applying the principle of homogeneity, while the opposite principle of specification was neglected; whereas the law of specification has led to the greatest and most important results. I therefore crave permission to
