"An accurate definition of a mystic is one who believes that he can reach truth intuitively; that he can reach truth within himself without reference to man's experiences; that he has mystical power to reach in himself and achieve what he would call truth; while the realist, of course, follows the scientific method of laboratory tests, scrupulous regarding of every fact and very careful observation. They are two separate mentalities, two hopelessly different personalities, and I can't imagine a good scientist permitting himself to become a mystic, though there are a few, and the few mystical scientists are those who are giving such comfort to the theologians; men like Eddington and Millikan, who are very good physicists, who are men of science in their own laboratories, but when they step out in the arena of philosophical thought they utter ideas that would pass for pretty good coin among the fanatics in a Salvation Army band. I think I am speaking pretty literally, because some of their arguments are the same arguments used on the street corners. In Eddington's latest plea before the Society of Friends in London, just a few months ago, and of course for that reason more important than his book, 'The Nature of the Physical World,' that he wrote about three years ago, he says that the reason the religious idea is sound is because there is proof of it in man's experience, man has experienced religion, he has experienced God, therefore it is true. Well, according to that, same logic, the poor moron who gets up on the street corner and gives his testimonial is scientific and it is absolutely right and everything that he says is true, every philosophical point that he is bringing out must be so, because he says he has experienced it; and that, of course, is mysticism. Eddington does not reach that conclusion through scientific means. He does not take the same methods that he used in his laboratory, to bring out that idea. He just simply reaches down into his insides and intuitively reaches that opinion, and I leave it to any reasonable person that it is completely without validity."
SOURCE: Is Theism A Logical Philosophy: Debate between E. Haldeman-Julius and Rev. Burris Jenkins, April 13, 1930.