• Noun: a piece of information about circumstances that exist or events that have occurred; example: "first you must collect all the facts of the case"
• Noun: a statement or assertion of verified information about something that is the case or has happened; example: "he supported his argument with an impressive array of facts"
• Noun: an event known to have happened or something known to have existed; examples: "your fears have no basis in fact", "how much of the story is fact and how much fiction is hard to tell"
• Noun: a concept whose truth can be proved; example: "scientific hypotheses are not facts"
The animal is ignorant of the fact that he knows. The man is aware of the fact that he is ignorant.
It's a very complicated issue about when is a fact not a fact in the context of opinions.
In scientific work, those who refuse to go beyond fact rarely get as far as fact.