The worst fact is better than the best opinion.

Any clod can have the facts, but having opinions is an art

He wasn't exactly hostile to facts, but he was apathetic about them

The man who questions opinions is wise. The man who quarrels with facts is a fool.

I am not one of those who in expressing opinions confine themselves to facts

The formal scientific definition of theory is quite different from the everyday meaning of the word. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence.