Only a scientific people can survive in a scientific future.

The medieval university looked backwards; it professed to be a storehouse of old knowledge. The modern university looks forward, and is a factory of new knowledge.

The only question which any wise man can ask himself, and which any honest man will ask himself, is whether a doctrine is true or false.

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.

It is not who is right, but what is right, that is of importance.

Thoughtfulness for others, generosity, modesty, and self-respect are the qualities which make a real gentleman or lady.

Agnosticism, in fact, is not a creed, but a method, the essence of which lies in the rigorous application of a single principle. ... Positively the principle may be expressed: In matters of the intellect, follow your reason as far as it will take you, without regard to any other consideration. And negatively: In matters of the intellect, do not pretend that conclusions are certain which are not demonstrated or demonstrable.