The divine Plato and the marvellous Kant unite their mighty voices in recommending a rule, to serve as the method of all philosophising as well as of all other science.[11] Two laws, they tell us: the law of _homogeneity_ and the law of _specification_, should be equally observed, neither to the disadvantage of the other. The law of _homogeneity_ directs us to collect things together into kinds by observing their resemblances and correspondences, to collect kinds again into species, species into genera, and so on, till at last we come to the highest all-comprehensive conception. Now this law, being transcendental, _i.e._ essential to our Reason, takes for granted that Nature conforms with it: an assumption which is expressed by the ancient formula, _entia præter necessitatem non esse multiplicanda_. 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 _à 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. [11] Platon, "Phileb." pp. 219-223. "Politic." 62, 63. "Phædr." 361-363, ed. Bip. Kant, "Kritik der reinen Vernunft. Anhang zur transcend. Dialektik." English Translation by F. Max Müller. "Appendix to the Transc. Dialectic." pp. 551, and _seqq._ § 2. _Application of the Method in the present case._