Note 29 — APHORISMS—BOOK I ON THE INTERPRETATION OF NATURE AND THE EMPIRE OF MAN
Reading edition
In mechanics and the general sciences, causes compound their effects, or in other words, it is generally possible to deduce à priori the consequence of introducing complex agencies into any experiment, by allowing for the effect of each of the simple causes which enter into their composition. In chemistry and physiology a contrary law holds; the causes which they embody generally uniting to form distinct substances, and to introduce unforeseen laws and combinations. The deductive method here is consequently inapplicable, and we are forced back upon experiment.