The glory of science is, that it is freeing the soul, breaking the mental manacles, getting the brain out of bondage, giving courage to thought, filling the world with mercy, justice, and joy.

Progress is born of doubt and inquiry. The Church never doubts, never inquires. To doubt is heresy, to inquire is to admit that you do not know—the Church does neither.

There is the same difference between talent and genius that there is between a stone mason and a sculptor

Fear is a dagger with which hypocrisy assassinates the soul.

All religion is slavery.

Darwin has done more to change human thought than all the priests who have existed.

One good schoolmaster is worth a thousand priests.