“Those whose acquaintance with scientific research is derived chiefly from its practical results easily develop a completely false notion of the mentality of the men who, surrounded by a skeptical world, have shown the way to kindred spirits scattered wide through the world and through the centuries. Only one who has devoted his life to similar ends can have a vivid realization of what has inspired these men and given them the strength to remain true to their purpose in spite of countless failures. It is cosmic religious feeling that gives a man such strength. A contemporary has said, not unjustly, that in this materialistic age of ours the serious scientific workers are the only profoundly religious people.”

“I maintain that the cosmic religious feeling is the strongest and noblest motive for scientific research.”

“I have treated many hundreds of patients. Among those in the second half of life - that is to say, over 35 - there has not been one whose problem in the last resort was not that of finding a religious outlook on life. It is safe to say that every one of them fell ill because he had lost that which the living religions of every age have given their followers, and none of them has really been healed who did not regain his religious outlook.”

“Today everybody admits that something is wrong with the world, and the critics of Christianity are the very people who feel this most. The most violent attacks on religion come from those who are most anxious to change the world, and they attack Christianity because they think that it is an obstructive force that stands in the way of a real reform of human life. There has seldom been a time in which men were more dissatisfied with life and the more conscious of the need for deliverance, and if they turn away from Christianity it is because they feel that Christianity is a servant of the established order and that it has no real power or will to change the world and to rescue man from his present difficulties. They have lost their faith in the old spiritual traditions that inspired civilization in the past, and they tend to look for a solution in some external practical remedy such as communism, or the scientific organisation of life; something definite and objective that can be applied to society as a whole.”

“To whatever degree he may have desacralized the world, the man who has made his choice in favor of a profane life never succeeds in completely doing away with religious behavior.”

“[Responding to the Bishop of Oxford, Samuel Wilberforce's question whether he traced his descent from an ape on his mother's or his father's side]A man has no reason to be ashamed of having an ape for his grandfather. If there were an ancestor whom I should feel shame in recalling it would rather be a man—a man of restless and versatile intellect—who … plunges into scientific questions with which he has no real acquaintance, only to obscure them by an aimless rhetoric, and distract the attention of his hearers from the real point at issue by eloquent digressions and skilled appeals to religious prejudice.”