Doubt

The old believe everything; the middle aged suspect everything: the young know everything

Better to keep your mouth shut and appear stupid than to open it and remove all doubt

Only two things are infinite, the universe and human stupidity, and I’m not sure about the former

When in doubt tell the truth

The greatest mistake you can make is to be continually fearing you will make one

When in doubt, don’t

In faith there is enough light for those who want to believe and enough shadows to blind those who don't.

Faith means belief in something concerning which doubt is theoretically possible

Doubt is a pain too lonely to know that faith is his twin brother

If one does not know to which port one is sailing, no wind is favorable

You will never be happy if you continue to search for what happiness consists of. You will never live if you are looking for the meaning of life.

Jealousy is that pain which a man feels from the apprehension that he is not equally beloved by the person whom he entirely loves

He who doubts from what he sees will never believe, do what you please

The grand perhaps! We look on helplessly, there the old misgivings, crooked questions are

There are times when patience proves at fault

I would think the extra pair of eyes, extra pair of ears would maybe deter someone who may have decided to try something

Undoubtedly a man is to labor to better his condition, but first to better himself

Test yourself on mankind. It is something that makes the doubter doubt, the believer believe.

Never look backwards or you'll fall down the stairs.