Scientists investigate that which already is; Engineers create that which has never been.

People love chopping wood. In this activity one immediately sees results.

In the middle of every difficulty lies opportunity.

All such action would cease if those powerful elemental forces were to cease stirring within us.

Lasting harmony with a woman (was) an undertaking in which I twice failed rather disgracefully.

There two things that are infinite, human stupidity and the universe, I don't know about the universe

Have the courage to take your own thoughts seriously, for they will shape you.