Philosophers have been worrying about the question of how you can know anything for thousands of years. I promise that your pithy answer here is not it.
I don’t think that’s an argument from authority. “Experts have been discussing X without reaching a conclusion for a long time” is a premise from which a reasonable argument can be made for the unlikelihood that an off-hand comment on HN has solved X. Argument from authority doesn't take that form though the two do have invoking authorities in common.
