Comte does not think so. This applied logic does not appear to him to be more indispensable than formal logic. In the first place, the former, in fact, supposes the latter. It proceeds from the same philosophical conception. In order to determine _a priori_, in a general way, the rules of the application of the mind to its various scientific objects, we should first have to possess a knowledge of the laws of the mind. But, according to Comte, this knowledge can only be obtained by the observation of the methods which the mind has indeed followed. Moreover, no art is taught abstractedly, not even the art of reasoning well, nor that of experimenting, of finding hypotheses, etc. It has never been sufficient to know the rules of versification in order to write true poetry. A deep knowledge of the rules of method will not lead to scientific discoveries.[85] Whatever we learn of an art, it is practice that has taught us. Nothing here can replace time, natural disposition, and experience. Methods then cannot be studied apart from the positive researches in which men of learning make use of them. Even supposing that in the far future, when the sciences are advanced, the methods and their applications could be taught by themselves, the study would run a great risk of yielding poor results.[86] Up to the present time all that has been said of the method, considered in the abstract, reduces itself to vague generalities. When, in logic, we have thoroughly established that all our science of nature must be founded upon observation, that we must proceed sometimes from facts to principles, sometimes from principles to facts, and a few other similar aphorisms, we know far less of the method than the man who has studied a single one of the positive sciences somewhat deeply, even without any philosophical purpose. It is thus that Eclectic philosophers have imagined to make their psychology into a science, thinking they could understand and practice the positive method because they had read the _Novum Organum_ and the _Discours de la Méthode_. But did not Bacon, Pascal, Descartes, and the other great scientific leaders insist on the uselessness of abstract considerations about method? They never separated the rules they formulated from their application to positive research.