I would rather have questions that can't be answered than answers that can't be questioned.

The first principle is that you must not fool yourself -- and you are the easiest person to fool.

Rule No. 1: Never lose money. Rule No. 2: Never forget Rule No. 1.

-- Warren Buffett

Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.

-- Albert Einstein

If you can't explain it simply, you don't understand it well enough.

-- Albert Einstein

A new scientific truth does not triumph by convincing its opponents, but rather because its opponents eventually die and a new generation grows up familiar with it.

-- Max Planck

An expert is a man who has made all the mistakes which can be made, in a narrow field.

-- Niels Bohr

However difficult life may seem, there is always something you can do and succeed at.

-- Stephen Hawking