Only a scientific people can survive in a scientific future.

The supernatural is being swept out of the universe in the flood of new knowledge of what is natural. It will soon be as impossible for an intelligent, educated man or woman to believe in a god as it is now to believe that earth is flat, that flies can be spontaneously generated, that disease is a divine punishment, or that death is always due to witchcraft.

Ecclesiasticism in science is only unfaithfulness to truth

If the hypothesis of evolution is true, living matter must have arisen from non-living matter; for by the hypothesis the condition of the globe was at one time such, that living matter could not have existed in it, life being entirely incompatible with the gaseous state.

In scientific work, those who refuse to go beyond fact rarely get as far as fact.

To quarrel with the uncertainty that besets us in intellectual affairs would be about as reasonable as to object to live one's life with due thought for the morrow because no man can be sure he will alive an hour hence.

I really see no harm which can come of giving our children a little knowledge of physiology. ... The instruction must be real, based upon observation, eked out by good explanatory diagrams and models, and conveyed by a teacher whose own knowledge has been acquired by a study of the facts; and not the mere catechismal parrot-work which too often usurps the place of elementary teaching.