I am proceeding, as you see, in this essay, from an hypothesis which, as far as such readers as I want are concerned, does not require to be proved; the hypothesis that "sinfulness" in man is not an actual fact, but rather merely the interpretation of a fact, of a physiological discomfort,--a discomfort seen through a moral religious perspective which is no longer binding upon us. The fact, therefore, that any one feels "guilty," "sinful," is certainly not yet any proof that he is right in feeling so, any more than any one is healthy simply because he feels healthy. Remember the celebrated witch-ordeals: in those days the most acute and humane judges had no doubt but that in these cases they were confronted with guilt,--the "witches"_ themselves had no doubt on the point_,--and yet the guilt was lacking. Let me elaborate this hypothesis: I do not for a minute accept the very "pain in the soul" as a real fact, but only as an explanation (a casual explanation) of facts that could not hitherto be precisely formulated; I regard it therefore as something as yet absolutely in the air and devoid of scientific cogency--just a nice fat word in the place of a lean note of interrogation. When any one fails to get rid of his "pain in the soul," the cause is, speaking crudely, to be found _not_ in his "soul" but more probably in his stomach (speaking crudely, I repeat, but by no means wishing thereby that you should listen to me or understand me in a crude spirit). A strong and well-constituted man digests his experiences (deeds and misdeeds all included) just as he digests his meats, even when he has some tough morsels to swallow. If he fails to "relieve himself" of an experience, this kind of indigestion is quite as much physiological as the other indigestion--and indeed, in more ways than one, simply one of the results of the other. You can adopt such a theory, and yet _entre nous_ be nevertheless the strongest opponent of all materialism. 17.