They also show that man's senses have been his arch-deceivers, and his preconceptions their abettors, throughout human history; that advance has been possible only as he has escaped through the discipline of the intellect from the illusive impressions about phenomena which the senses convey. Upon this matter the words of the late Dr. Carpenter may be quoted, words the more weighty because they are the utterance of a man whose philosophy was influenced by deep religious convictions: "With every disposition to accept facts when I could once clearly satisfy myself that they were facts, I have had to come to the conclusion that whenever I have been permitted to employ such tests as I should employ in any scientific investigation, there was either intentional deception on the part of interested persons, or else self-deception on the part of persons who were very sober-minded and rational upon all ordinary affairs of life." He adds further: "It has been my business lately to inquire into the mental condition of some of the individuals who have reported the most remarkable occurrences. I cannot--it would not be fair--say all I could with regard to that mental condition; but I can only say this, that it all fits in perfectly well with the result of my previous studies upon the subject, viz., that there is nothing too strange to be believed by those who have once surrendered their judgment to the extent of accepting as credible things which common sense tells us are entirely incredible."