MIND

"Man's mind is his basic tool of survival. Life is given to him, survival is not. His body is given to him, its sustenance is not. His mind is given to him, its content is not. To remain alive, he must act, and before he can act he must know the nature and purpose of his action. He cannot obtain his food without a knowledge of food and of the way to obtain it. He cannot dig a ditch – or build a cyclotron – without a knowledge of his aim and of the means to achieve it. To remain alive, he must think. But to think is an act of choice."  ~ From John Galt's speech in Atlas Shrugged by Ayn Rand.

The Brevity Of Life

"It's not at all that we have too short a time to live, but that we squander a great deal of it. Life is long enough, and it's given in sufficient measure to do many great things if we spend it well. But when it's poured down the drain of luxury and neglect, when it's employed to no good end, we're finally driven to see that it has passed by before we even recognised it passing. And so it is - we don't receive a short life, we make it so."
~ Seneca the Younger, a Roman Stoic philosopher, Statesman and dramatist.