Benjamin Rush

Were I disposed to consider the comparative merit of each of them [facts or theories in medical practice], I should derive most of the evils of medicine from supposed facts, and ascribe all the remedies which have been uniformly and extensively useful, to such theories as are true. Facts are combined and rendered useful only by means of theories, and the more disposed men are to reason, the more minute and extensive they become in their observations

It would seem from this fact, that man is naturally a wild animal, and that when taken from the woods, he is never happy in his natural state, 'till he returns to them again.