The problem is that Galactica spits out obvious nonsense while being completely unaware of that. Okay, the real problem is that it also spits out nonobvious nonsense, where the human reader may also be unaware of it, along with Galactica. The only thing it does reasonably well is to generate text that sounds plausible in tone and form.
Science can't identify the truth. It can only identify what is NOT true. As our knowledge expands, we get closer to discovering the truth; but we can never be sure we've arrived.