FLOYD: I don't suppose you have any idea what the damn thing is.
HALVORSEN: I wish to hell we did. Nope, the only thing we're sure of is that it was buried 4 million years ago.
FLOYD: Well, I must say, you guys have certainly come up with something.
The scientists of Clavius base have uncovered the monolith, but this great discovery doesn't instantly reveal its nature or purpose to them. In true scientific fashion, they must continue to research and study it in the hopes of one day uncovering its secrets. As Fox Mulder said so many times, the truth is out there. Of course, he also said "Trust no one," so there's that.
HAL: Well, it's rather difficult to define. Perhaps I'm just projecting my own concern about it. I know I've never completely freed myself from the suspicion that there are some extremely odd things about this mission. I'm sure you'll agree there's some truth in what I say.
HAL has the truth, kept from the astronauts, stored in his data. Later Bowman will discover the video providing him the truth about the mission. For now, we're left to wonder: Is HAL conscious of the truth? Is his inability to share that truth corrupting him? Is lying ultimately the source of all the trouble on board the spacecraft?
HAL: Yes, I have a good track.
BOWMAN: Do you know what happened?
HAL: I'm sorry, Dave. I don't have enough information.
BOWMAN: Open the pod door, HAL.
Although HAL has been acting weird up until now, this is the first instance of his flat-out, unequivocally lying to a human being. Does being able to lie make him seem more human?
HAL: I know I've made some very poor decisions recently, but I can give you my complete assurance that my work will be back to normal. I've still got the greatest enthusiasm and confidence in the mission, and I want to help you.
In an utterly human moment, HAL abandons the truth entirely. It's willing to say anything to convince Bowman from disconnecting it.
FLOYD: Eighteen months ago, the first evidence of intelligent life off the Earth was discovered. It was buried 40 feet below the lunar surface near the crater Tycho. Except for a single, very powerful radio emission aimed at Jupiter, the 4-million-year-old black monolith has remained completely inert. Its origin and purpose still a total mystery.
The truth about the mission is revealed just in time for it not to save anyone's life. Of course, like all the truth so far in the movie, these answers only lead us to more questions, and those questions take us to Jupiter.
The Star Child returns to Earth. Orbiting the planet that was the birthplace and galactic cradle to humanity, the Star Child stares into an unknown future.
The truth ultimately evades us. We know the extraterrestrials have transformed Bowman into a new being, but we don't know how or why. In many ways, that's the entire point of the film. We'll just have to keep on looking.