SIR: In your editorial, in the issue of September, you speak of “faith as the organ of religious apprehension.” This suggests some important facts that are not always apprehended, or are forgotten. There is no organ for the discovery, the proof, or the apprehension of truth but reason, whether facts of Nature or of religion. “Faith” is not a sixth sense which we do not use in scientific pursuits, but which comes to our help when we seek for religious truth. Much of the difficulty comes from the fact that the word “faith” is ambiguous, having two meanings, which are not distinguished. It is (1) simply belief of a fact because of evidence presented to and apprehended by the reason; or is it (2) trust, confidence in, belief in, as in a person, resting on the belief of that person’s competency and truthfulness, that belief resting on evidence apprehended by the reason. Because of this “faith” in the person we accept his testimony as to facts beyond our personal cognizance, we believe them not because we have discovered them, or may be are competent to discover them, but because of our “faith” in a person whom we have seen reason to believe is trustworthy--i. e., competent and truthful. Now, these two meanings of “faith” are often confused, interchanged. Hence the discredit thrown upon belief of religious truth, because an illegitimate use is made of the place of “faith” in its justification. And writers defending religious belief have been great sinners in this illegitimate use of “faith.” The place of “faith” is the same in science as in religion--i. e., it is the condition and justification of our acceptance of truth which is beyond our personal cognizance. We accept it because of the testimony of men in whom we have learned to have faith--e.g., How few of us who accept the revelations of the spectrum analysis as to the composition of the stars have any other justification for accepting them than just this? We believe them simply because men, whom we, in the exercise of our reason, have come to believe competent and truthful, tell us what they have seen. We believe on their testimony because we trust them. Our process involves three steps: (1) Belief of their competence through appeal to reason; (2) trust in them because of this belief; (3) belief of their testimony because of this trust or “faith” in them. The only organ we have used is reason, in its initial act of belief of the competence and truthfulness of the witnesses. Error in the use of reason here vitiates all that follows. Correct use of reason here gives a legitimate condition for correct results of the other steps. But reason must go along with us and guide us in these, that we may come to a rationally accepted belief of the truth. Here is the place of “faith” in science, as belief and as trust. By its use we accept the great issues of scientific truth which we believe, and do it legitimately.