A fact is an empirically provable piece of information. Until it can be proven, it is a theory, and discussion on what that information "means" as applied to other things is an opinion.
"I am male", that is fact because we have defined certain body parts to mean "male".
"I can grow a beard because I am male." Theory, as I have never grown a full one so it theoretically possible (and likely given our available data on the subject) but unproven. In this regard, theories can be treated as factual if enough supporting evidence suggests it to be true, until new information is gathered.
"I am better at carpentry because I am male." A horribly sexist opinion as it is broad, unprovable and subject to interpretation as to what "better" means in relation to others as well as the work itself. Subjective.
And no, the full quote goes like this:
"This man, on one hand, believes that he knows something, while not knowing. On the other hand, I – equally ignorant – do not believe."
The quote means, he does not claim knowledge of things that he is ignorant of which is a completely different than claiming no knowledge of anything.
No, I do not want to have a debate with someone who chooses to ignore the very notion of a "fact" or "knowledge" as being possible. It makes it a waste of my time, of no interest to the other person, so how would that be beneficial to anyone?
The Philosophy Of Liberty -