Colin asked:

What if anything is the difference between fact and opinion?

============

In one meaning of the word "fact" a fact is something that can be shown to be true by accepted
methods. For instance, it is a fact that Mars is the fourth planet.

An opinion (or belief) is something that cannot be shown to be true by those who hold the opinion, by
any accepted method, although it may be true, and it may become a fact when and if accepted
methods are determined. For instance, it is an opinion, held by many people including some
astronomers, that there is extraterrestrial life.

A "matter of opinion" is different. Something is a matter of opinion when it is not something that can
be shown true or false, but is "subjective". For instance, whether vanilla ice cream tastes better than
strawberry ice-cream is a matter of opinion that no one should quarrel about. Matters of opinion are
not true or false, or something we very much care whether they are true or false. "Matter of opinion" is
pretty much the same as "matter of taste".

"My opinion" or "only my opinion" (with emphasis on the "my") usually means a view or belief I
happen to hold, but do not expect others to share. For instance, "I think that eating stewed prune
ice-cream is disgusting, but that's only my opinion".

Ken Stern

A 'fact' is something that has actually happenedor an action actually performed (the latter of course is
just a special case of the former). For you to say, "the sky is blue and that's a fact" is therefore not
strictly speaking a proper way of expressing it, although one would have to be an extreme pedant to
ignore what's become pretty common language usage. At any rate, a fact (providing it is adequately
testified) is once and for all time. Thus we accept that Julius Caesar was assassinated on the Ides of
March, even though no one can prove it. The testimony, however, is reliable. An opinion, on the
contrary, is a belief you hold, and there may be times when this is in contradiction to facts. So there is
this difference to begin with. Further, many people change their opinion often; and accordingly
opinions can fluctuate all the way from virtual certainty (expert opinion) to a mere whim. In philosophy
you will often find the syllable "dox" (as in paradox, orthodox) attached to a word to denote that the
matter in question is an opinion. Plato distinguished between "doxa" and "episteme", that is, between
opinion and knowledge; but then Plato had a pretty rarefied notion of knowledge which in today's
world might be difficult to insist on — I mean: there is a solid body of philosophical opinion that all
knowledge is just opinion ...

Jurgen Lawrenz

Sydney