While circular reasoning should not be convincing (at least not usually), it should also not be considered invalid.
I don’t think that people who claim circular arguments are invalid tend to use “valid” in the rigorous logical sense, but as a synonym for “convincing” or “useful as an argument”. I know I don’t.
If the best evidence for a belief is circular, it’s probably wrong. Honesly, on this level, all models are wrong—I should say “not terribly useful”.
I don’t think that people who claim circular arguments are invalid tend to use “valid” in the rigorous logical sense, but as a synonym for “convincing” or “useful as an argument”. I know I don’t.
If the best evidence for a belief is circular, it’s probably wrong. Honesly, on this level, all models are wrong—I should say “not terribly useful”.