I don't think there is a such thing as actually true. You can have two beliefs that like are inconsistent with each other, but there's nothing that's false. So let's say I have a very vivid dream and in my dream, I don't know I'm dreaming and there are atoms, the universe made of atoms in this dream,. And then in the dream, I run some tests to see if they're there or not. If someone claims there are atoms there, then you could go and try to validate whether that's true or not. But ultimately it is just a thing that you're experiencing.