Let him resolve some morning that he will proceed that day from task to task without allowing such thoughts to intrude. If he does so he will find that he has succeeded in his work at least as well as usual, and that he is comparatively fresh in the evening. Why not try this every day? * * * * * So far we have only considered the most obvious and simple among the evidences of doubting folly. A still more obstinate tendency of the doubter is the insistent habit interminably to argue over the simplest proposition, particularly regarding matters pertaining to the health, comfort, and life of the individual himself. A certain patient, of this type, attempts to describe to his physician a peculiar, hitherto undescribed, and even now indescribable sensation "through his right lung." He traces this sensation to what he believes to have been the absorption of a poison some years ago. His line of reasoning is somewhat as follows: 1. The drug was a poison. 2. If he absorbed it he must have been poisoned. 3. If he was poisoned then, he is poisoned now. 4. There is no proof that such a poison cannot produce such a sensation. 5. He has the sensation. Conclusion: He is suffering from poison. In support of this proposition he will spend hours with anyone who will listen. The physician who allows himself to be drawn into the controversy speedily finds himself, instead of giving advice to listening ears, involved in a battle of wits in which he is quite likely to come off second best. He assures the patient, for example, that, as far as scientific methods can establish the fact, the lung is sound. "But has science established everything? And if it had, is such negative evidence to be weighed against the positive evidence of the sensation in my lung?" "But the sensation may not be in your lung." "Can you prove that it is _not_ in my lung?" Folly scores! On being urged to direct his attention to some other part of his body, he promptly inquires, "How can I direct my thoughts elsewhere, when the sensation is there to occupy my attention?" Obviously he can not without changing his mental attitude, so folly scores again. He is assured that if the poison had been absorbed the effects would have passed away long before this time. "But do the effects of poison _always_ pass away? And can you _prove_ that they have passed away in my case? Is not the sensation positive evidence, since you have allowed that you cannot prove that the sensation does _not_ come from the poison?" Folly scores again, but the victory is an empty one. The vicious circle continues: Attention magnifies sensation--sensation produces fear--fear increases attention; and throughout runs the insistent thought that his sensations shall conform to his ideal.