If I prove something, does it have to be true?
I can structure the question more convolutedly: Does successfully proving something depend on the credulity of the audience, or the truth of the argument?
NOAD defines the word:
prove, v. demonstrate the truth or existence of (something) by evidence or argument
Other dictionaries are similar. I find it unclear, though, whether 'demonstrating truth' requires something be true.
The problem mainly arises in historical arguments. In matters we still don't know, the distinction doesn't matter—"She proved God exists" vs. "She proved God doesn't exist"—because we don't know the truth. Some things, though, were previously thought to be true that are no longer considered to be true (cf. science). When writing after an idea has been disproved, should we still say it was proven?
Copernicus proved that the earth rotated around the sun. We still believe this. However, he also argued that the planets rotated the sun in perfectly circular orbit and that the sun was the center of the universe. At the time it would have made unequivocal sense to say he proved that the sun was the center of the universe. Now, however, we no longer believe the sun is the center of the universe, or that planets rotate it in perfect circles.
Is it correct, today, after Kepler et al, to say Copernicus proved the sun was the center of the universe?
Why does this matter? If I read that someone proved something, should I trust that their finding is true?