Great minds struggle to cure diseases so that people may live longer, but only madmen ask why. One lives longer in order that he may live longer. There is no other purpose.

It's so hard when contemplated in advance, and so easy when you do it.

The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed.

How are you going to teach virtue if you teach the relativity of all ethical ideas? Virtue, if it implies anything at all, implies an ethical absolute. A person whose idea of what is proper varies from day to day can be admired for his broadmindedness, but not for his virtue.

Metaphysics is a restaurant where they give you a thirty thousand page menu, and no food.

One thing about pioneers that you don't hear mentioned is that they are invariably, by their nature, mess-makers. They go forging ahead, seeing only their noble, distant goal, and never notice any of the crud and debris they leave behind them.

And what is good, Phaedrus, And what is not good— Need we ask anyone to tell us these things?