Thought is subversive and revolutionary, destructive and terrible, Thought is merciless to privilege, established institutions, and comfortable habit. Thought is great and swift and free.

If we were all given by magic the power to read each other's thoughts, I suppose the first effect would be to dissolve all friendships.

What is best in mathematics deserves not merely to be learnt as a task, but to assimilated as a part of daily thought, and brought again and again before the mind with ever-renewed encouragement.

Science is no substitute for virtue; the heart is as necessary for a good life as the head.

You find as you look around the world that every single bit of progress in humane feeling, every improvement in the criminal law, every step toward the diminution of war, every step toward better treatment of the colored races, or every mitigation of slavery, every moral progress that there has been in the world, has been consistently opposed by the organized churches of the world. I say quite deliberately that the christian religion, as organized in its churches, has been and still is the principle enemy of moral progress in the world.

We have almost reached the point where praise of rationality is held to mark a man as an old fogey regrettably surviving from a bygone age.

There is much pleasure to be gained from useless knowledge.