I will frankly tell you that my experience in prolonged scientific investigations convinces me that a belief in God-a God who is behind and within the chaos of vanishing points of human knowledge-adds a wonderful stimulus to the man who attempts to penetrate into the regions of the unknown.

Philosophers and theologians have yet to learn that a physical fact is as sacred as a moral principle. Our own nature demands from us this double allegiance.

A laboratory of natural history is a sanctuary where nothing profane should be tolerated. I feel less agony at improprieties in churches than in a scientific laboratory.

Select such subjects that your pupils cannot walk out without seeing them. Train your pupils to be observers, and have them provided with the specimens about which you speak. If you can find nothing better, take a house-fly or a cricket, and let each one hold a specimen and examine it as you talk.

The facts will eventually test all our theories, and they form, after all, the only impartial jury to which we can appeal.

The eye of the trilobite tells us that the sun shone on the old beach where he lived; for there is nothing in nature without a purpose, and when so complicated an organ was made to receive the light, there must have been light to enter it.

I sometimes hear preachers speak of the sad condition of men who live without God in the world, but a scientist who lives without God in the world seems to me worse off than ordinary men.