When a man's knowledge is not in order, the more of it he has the greater will be his confusion.

Be bold, be bold, and everywhere be bold.

Agnostics are people who, like myself, confess themselves to be hopelessly ignorant concerning a variety of matters, about which metaphysicians and theologians, both orthodox and heterodox, dogmatize with the utmost confidence.

No one can be perfectly free till all are free; no one can be perfectly moral till all are moral; no one can be perfectly happy till all are happy.

To have a specific style is to be poor in speech.

In science the important thing is to modify and change one's ideas as science advances.

Absolute morality is the regulation of conduct in such a way that pain shall not be inflicted.