Lack of activity destroys the good condition of every human being

When men speak ill of thee, live so that nobody will believe them.

People too smart to get involved in politics are doomed to live in societies run by people who aren't.

Science is nothing but perception.

Socrates said that, from above, the Earth looks like one of those twelve-patched leathern balls.

Each man is capable of doing one thing well. If he attempts several, he will fail to achieve distinction in any.

And isn't it a bad thing to be deceived about the truth, and a good thing to know what the truth is? For I assume that by knowing the truth you mean knowing things as they really are.