What confuses me about the notion of a fact, is that it seems like it's something that's discovered. So, a fact could be said to be this 'thing' that has a perfect correspondence with reality, and when one comes to know of a fact, they come to know part of true reality i.e the way the world really is.
If there were no thinking being in the world, we would want to say there are still facts of the world, after all, such facts is what would be discovered, or at least some facts, if there were (which of course there are) to be beings capable of thought.
Perhaps then, facts are just the potential for objects, their properties, and relations to known by a thinking being. So if there were no thinking beings, we can still say that there are facts, for if there were, said facts still have the potential to be expressed.
But (horay!), what if there is something about the nature of reality that is literally unknowable. It's every bit as real as everything else, but no mind, no matter how sophisticated, could ever come to know of such a fact. And actually, the question doesn't make technical sense, for the definition of a fact just given does not allow for 'unknowable' facts, since it bears no potential to be known, or even thought about. But it does have alot of intuitive sense, so we may want to revise our definition of a fact.
What then, is the solution? It seems as if we should very much keep the condition that a fact is this perfect correspondence to reality, that's what everything is revolving around. Do we eliminate the need of potentiality (to be known) then, and keep the condition of correspondence (of fact and reality)? If so, we're back at trying to determine what a fact actually is. We can't invoke the notion of potentiality again because that would cause the same problem.
However, we've arrived at a contradiction. We could say that facts don't exist, but then what bears the potential to be thought about, and to expressed? However, this notion of potentiality has its own problems, yet we can't seem to do without.
So ultimately, what actually is the ontological components of a fact? Can the condition of potentiality be replaced, so as to satisfy, completely, what a fact is? Is there a satisfactory definition that could resolve any doubt, any criticism of what a fact actually is? Or is it undefinable, either by current means or just in and of itself?