All is to be doubted.

We do not describe the world we see, we see the world we can describe.

Whenever anyone has offended me, I try to raise my soul so high that the offense cannot reach it.

De omnibus dubitandum

Divide each difficulty into as many parts as is feasible and necessary to resolve it.

Conquer yourself rather than the world.

The reading of all good books is like a conversation with the finest minds of past centuries.

The chief cause of human errors is to be found in the prejudices picked up in childhood.

Doubt is the origin of wisdom

The only thing we have power over in the universe is our own thoughts.

How can you be certain that your whole life is not a dream?

With persistent focus and determined spirit, you can achieve the God-given goals.

A Man of wisdom is one who discusses everything other than his achievements, a Fool speaks only of his achievements

That's all a man can hope for during his lifetime - to set an example - and when he is dead, to be an inspiration for history.

So vast is art, so narrow human wit.

We are gods. Our tools make us gods. In symbiosis with our technology, our powers are expanding exponentially and so, too, our possibilities.

At a certain point, you realize you have a responsibility more behind yourself and your need for adrenaline. I'm glad I did things in my 20s that were more reckless.

Analogies are figures intended to serve as fatal weapons if they succeed, and as innocent toys if they fail.

Taxpayers don't need any more big government mandates that have proven to be disastrous.

We all have our worries about our bodies and our looks. We just need to make the best of our lovely, wonky selves. The key is never to compare and try to be something you're not.

We are speeding up our lives and working harder in a futile attempt to buy the time to slow down and enjoy it.