Reality is merely an illusion, albeit a very persistent one.
The only real valuable thing is Intuition.

Sometimes one pays most for the things one gets for nothing.
Anyone who has never made a mistake has never tried anything new.

 Everything should be made as simple as possible but not simpler

 Common sense is the collection of prejudices acquired by age  eighteen.

 The secret to creativity is knowing how to hide your sources.
 Peace cannot be kept by force. It can only be achieved by understanding.

We can't solve problems by using the same kind of thinking  we used when we created them.
The important thing is not to stop questioning.

 If A is a success in life, then A equals x plus y plus z. Work is x; y is play; and z is keeping your mouth shut.    

 Imagination is more important than knowledge.
Gravitation is not responsible for people falling in love.