“ The frequent or invariable recurrence of similar series of events gives birth in the mind to what are wrongly called “laws”; in fact, these “laws” are merely statements of experience gathered together by association, and have no other kind of validity. In other words from the empirical standpoint the statement of such a “law” does not contain the word “must”; it merely asserts that such and such series have been invariably observed. In this theory there can strictly be no “causation”; one thing is observed to succeed another, but observations cannot assert that it is “caused” by that thing ”

“ The idea of necessary connexion is a purely mental idea, an a priori conception, in which observation of empirical data takes no part; empiricism in ethics likewise does away with the idea of the absolute authority of the moral law as conceived by the intuitionalists. The moral law is merely a collection of rules of conduct based on an infinite number of special cases in which the convenience of society or its rulers has subordinated the inclination of individuals. The fundamental objection to empiricism is that it fails to give an accurate explanation of experience ”

“ In medicine, the term is applied to a school of physicians who, in the time of Celsus and Galen, advocated accurate observation of the phenomena of health and disease in the belief that only by the collection of a vast mass of instances would a true science of medicine be attained. ”