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

The improver of natural knowledge absolutely refuses to acknowledge authority, as such. For him, skepticism is the highest of duties; blind faith the one unpardonable sin.

I care not what subject is taught, if only it be taught well.

Only a scientific people can survive in a scientific future.

It is given to few to add the store of knowledge, to strike new springs of thought, or to shape new forms of beauty. But so sure as it is that men live not by bread, but by ideas, so sure is it that the future of the world lies in the hands of those who are able to carry the interpretation of nature a step further than their predecessors.

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

All truth, in the long run, is only common sense clarified.