I read a lot of books from the 80's and 90's, and I always get sad when I see the books mention Planet Pluto. As you may know, Pluto isn't a planet anymore. Poor Pluto.
From what I can tell, a bunch of scientists got together and decided Pluto isn't a planet. Is that all it takes? A bunch of scientists agree on something, and that makes it true or false? What about situations where scientists disagree? Does that make something true and not true at the same time?
Or when scientists change their minds, like they did with Pluto? Does that mean something can be true one week, and false the next? It seems kind of crazy that truth can be so malleable. I always through of truth as firm and unchanging, as in "something is true, even if no one believes it". Like, Neptune was a planet in 1500, and that's true, even though no one believed it.
I feel like this is partly why there's a problem with fake news. If your definition of truth is "[x] is true if a lot of people agree on it", that can cause problems. A lot of people think the world is flat, but that doesn't make it true!