David Hartley

“ The history of diseases, and their cures, is the basis of all; after this come anatomical examinations of the body, both in its natural and morbid states; and last of all, pharmacy; these three answering respectively to the general problem, and the two subordinate ones above-mentioned. And if we reason at all upon the functions and disorders of the parts, and the effects of medicines upon the body, so important an organ as the brain must not be left out entirely. ”

“ For where practice is silent, physicians must and will have recourse to some theory, good or bad. And if they do not acquaint themselves with the real structure and functions of the parts, with the sensible qualities and operations of medicines, and with the most probable method of explaining both the symptoms of distempers, and the operations of medicines, they must fancy something in the place of these, and reason from such false imaginations, or perhaps from the mere agreements, oppositions, and secondary ideas, of words. ”

“ It may not be amiss to add here, that as all the natural functions tend to the welfare of the body, so there is a remarkable tendency in all the disorders of the body to rectify themselves. These two tendencies, taken together, make what is called nature by physicians ”