I am a fool, but I know I'm a fool and that makes me smarter than you.

To move the world we must move ourselves.

To know, is to know that you know nothing. That is the meaning of true knowledge. For a man who claims to have knowledge, while actually knowing nothing, is less smarter than you, who claim to know nothing.

If thou continuous to take delight in idle argumentation thou mayest be qualified to combat with the sophists, but will never know how to live with men.

If we pursue our habit of eating animals, and if our neighbour follows a similar path, will we need to go to war against our neighbour to secure greater pasturage, because ours will not be enough to sustain us, and our neighbour will have a similar need to wage war on us for the same reason.

There is a doctrine whispered in secret that a man is a prisoner who has no right to open the door and run away; this is a great mystery which I do not quite understand.

Only the extremely ignorant or the extremely intelligent can resist change.