It is the theory that decides what can be observed.

The devil has put a penalty on all things we enjoy in life. Either we suffer in our health, or we suffer in our soul, or we get fat.

It is the supreme art of the teacher to awaken joy in creative expression and knowledge.

The satisfaction of physical needs is indeed the indispensable pre-condition of a satisfactory existence, but in itself it is not enough. In order to be content, men must also have the possibility of developing their intellectual and artistic powers to whatever extent accords with their personal characteristics and abilities.

Compound interest is the eighth wonder of the world. He who understands it, earns it ... he who doesn't ... pays it.

The same thinking and actions that created our problems cannot be used to solve them.

Given the millions of billions of Earth-like planets, life elsewhere in the Universe without a doubt, does exist. In the vastness of the Universe we are not alone.