The challenge we are going to face in this AI era is that the training data can be biased or include some morally/politically incorrect information. Someone can intentionally manipulate the data and make us feel that the response from the machine is trustworthy and factual, which can be devastating if it is used by a dictating government. Mind the alternative facts!!!
We can UNintentionally manipulate the data too even when we are trying our best to be honest.
You'll be hard pressed to find a single fact that would be considered so by the entire human population. There are people who are seriously disputing that the earth is round.
Well, it's sort of a very slightly lumpy oblate spheroid... it also ties into whether we agree on what "round" means.
There's a knowledge problem involved - when answering a question you really have to understand the knowledge and intent of the speaker, establish a conversational frame.
The first years of university are often spent learning certain "facts" and theories, which are technically incorrect (but useful), which will be torn down and shown as approximations later.
Even things that look like "hard" facts are very often a matter of perspective.