Some facts are relative. Yellow is a good color. That's an opinion, and also a fact for whoever holds the opinion but not necessarily true for everyone
. If you don't want to use the word fact there, the word truth suffices in it's place. Though this is just a semantic issue.
Your statement and mine about what an opinion is and how it is to be defined is completely debatable both ways, and actually "provable" both ways by quoting different definitions (Or dictionaries, however you want to phrase it). As I'm sure your aware, there are multiple different definitions for most words in English. Some vary a little from each other, and some vary a lot. I can hunt down a definition that proves my point entirely, you can choose to select a different definition that proves yours entirely. Depends on what wording you prefer to use really so I see it as a pointless debate from a logical perspective.
Most so called facts, are just opinions (I think that's a fact but I'll just say it's my opinion). You and I can both observe the exact same thing and come to entirely different conclusions. Things that have been "proven" as facts for years often turn out to be total hogwash and complete and utter false hoods decades later. Human beings do not dictate what the truth is, though most of us like to think we do. Consensus on a subject and labeling it as a fact does not make it true if it in reality happens to be false
, the thing is....most of the time people have no clue that this is the case, that's the only point I was making.
And it's not my definition of opinion. It's just a philosophical thought on the nature of opinion. My train of thought is a little deeper than mere semantics.