The a Priori Idea and Doubt in Experimental Reasoning
Experimental reasoning is the only reasoning that naturalists and physicians can use in seeking the truth and approaching it as nearly as possible. Experimental truths, on the contrary, are unconscious and relative, because the real conditions on which they exist are unconscious and can be known by us only in their relation to the present state of our science. The first condition to be fulfilled by men of science, applying themselves to the investigation of natural phenomena, is to maintain absolute freedom of mind, based on philosophic doubt. Counterproof is a necessary and essential characteristic of the conclusion of experimental reasoning. It is the expression of philosophic doubt carried as far as possible. The only proof that one phenomenon plays the part of cause in relation to another is by removing the first, to stop the second. The experimental method is characterized by being dependent only on itself, because it includes within itself its criterion,—experience.