Our greatest weakness lies in giving up. The most certain way to succeed is always to try just one more time.

The entity that gives life and motion to the human body is finer still and lies infinitely beyond the reach of our finest scientific instruments. When this entity deserts the body, the body is like a ship without a rudder - deserted, motionless, dead.

Accomplishing something provides the only real satisfaction in life.

Discontent is the first necessity of progress.

Fooling around with alternating currents is just a waste of time. Nobody will use it, ever. It's too dangerous . . . it could kill a man as quick as a bolt of lightning. Direct current is safe.

The inventor tries to meet the demand of a crazy civilization.

Keep on the lookout for novel ideas that others have used successfully. Your idea has to be original only in its adaptation to the problem you're working on.