Matter and force are the two names of the one artist who fashions the living as well as the lifeless.

My experience of the world is that things left to themselves don't get right.

The great end of life is not knowledge but action.

God give me strength to face a fact though it slay me.

Every great advance in natural knowledge has involved the absolute rejection of authority.

It is an error to imagine that evolution signifies a constant tendency to increased perfection. That process undoubtedly involves a constant remodeling of the organism in adaptation to new conditions; but it depends on the nature of those conditions whether the direction of the modifications effected shall be upward or downward.

What men need is, as much knowledge as they can assimilate and organize into a basis for action; give them more and it may become injurious. One knows people who are as heavy and stupid from undigested learning .