To invent, you need a good imagination and a pile of junk. - Thomas Edison

It is astonishing what an effort it seems to be for many people to put their brains definitely and systematically to work.

We really haven't got any great amount of data on the subject, and without data how can we reach any definite conclusions? All we have — everything — favors the idea of what religionists call the "Hereafter." Science, if it ever learns the facts, probably will find another more definitely descriptive term.

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