Letter 39

It will serve you well to learn the difference between a fact, and an opinion, as they are presented to you.

A proposed fact, as it is presented to you will be accompanied by evidence. That evidence may vary in its applicability and reliability, but it will be accompanied by some sort of proof.

An opinion need not immediately present its proof. This is because it makes no other assertion than "I believe this." Unless the presenter is being totally disingenuous, you can safely credit their belief - that they actually believe what they are saying.

But that proves nothing. Mental hospitals are full of people who believe untrue things, and believe them quite sincerely.

For example, one can say, "I believe in the virgin birth." Okay. So you believe it. That has no bearing on whether the assertion is true.

You can't really argue against an opinion, if the person believes that, they believe it. You can't very well tell them they DON'T believe what they claim to believe. This is why attempting to present opinions as facts is such a popular tactic. You can refute facts with more or better evidence. Opinions are not subject to such refutation.