From its point of view what does it mean "to know".

Is it the token (or set of tokens) that are strictly > 50% probable or is it just the highest probability in a set of probabilities?

While generating bullshit is not ideal for a lot of use cases you don't want your premier chat bot to say "I don't know" to the general public half the time. The investment in these things requires wide adoption so they are always going to favour the "guesses".