A woman's guess is much more accurate than a man's certainty.

If you have a choice between certainty and hope, choose certainty every time.

To be uncertain is to be uncomfortable, but to be certain is to be ridiculous.

There is nothing certain, but the uncertain.

Convictions are more dangerous enemies of truth than lies.

When we are not sure, we are alive.

What men want is not knowledge, but certainty.

The one unchangeable certainty is that nothing is unchangeable or certain.

The present is the only reality and the only certainty.

Doubt is not a pleasant mental state, but certainty is a ridiculous one.