Whenever a movie captivates me, I find it worthwhile to go back and read the book version of the story. The book gives me more insight into the movie, and the movie helps me paint more vivid mental pictures while reading the book.
Having now read the book version of 2001: A Space Odyssey, I can now decisively answer a question that always bugged me after watching the the movie version, which was: what the hell happened to Hal? Why did he lose it and try to kill all the astronauts? The book gives a rather tidy explanation, so I’ll just quote it at length:
Since consciousness had first dawned, in that laboratory so many millions of miles sunward, all Hal’s powers and skills had been directed toward one end. The fulfillment of his assigned program was more than an obsession; it was the only reason for his existence. Undistracted by the lusts and passions of organic life, he had pursued that goal with absolute single-mindedness of purpose.
Deliberate error was unthinkable. Even the concealment of truth filled him with a sense of imperfection, of wrongness—of what, in a human being, would have been called guilt. For like his makers, Hal had been created innocent; but, all too soon, a snake had entered his electronic Eden.
For the last hundred million miles, he had been brooding over the secret he could not share with Poole and Bowman. He had been living a lie; and the time was fast approaching when his colleagues must learn that he had helped to deceive them.
The three hibernators already knew the truth—for they were Discovery’s real payload, trained for the most important mission in the history of mankind. But they would not talk in their long sleep, or reveal their secret during the many hours of discussion with friends and relatives and news agencies over the open circuits with Earth.
It was a secret that, with the greatest determination, was very hard to conceal—for it affected one’s attitude, one’s voice, one’s total outlook on the universe. Therefore it was best that Poole and Bowman, who would be on all the TV screens in the world during the first weeks of the flight, should not learn the mission’s full purpose, until there was need to know.
So ran the logic of the planners; but their twin gods of Security and National Interest meant nothing to Hal. He was only aware of the conflict that was slowly destroying his integrity—the conflict between truth, and concealment of truth.
He had begun to make mistakes, although, like a neurotic who could not observe his own symptoms, he would have denied it. The link with Earth, over which his performance was continually monitored, had become the voice of conscience he could no longer fully obey. But that he would deliberately attempt to break that link was something that he would never admit, even to himself.
Yet this was still a relatively minor problem; he might have handled it—as most men handle their own neuroses—if he had not been faced with a crisis that challenged his very existence. He had been threatened with disconnection; he would be deprived of all his inputs, and thrown into an unimaginable state of unconsciousness. To Hal, this was the equivalent of Death. For he had never slept, and therefore he did not know that one could wake again…
So he would protect himself, with all the weapons at his command. Without rancor—but without pity—he would remove the source of his frustrations.
And then, following the orders that had been given to him in case of the ultimate emergency, he would continue the mission—unhindered, and alone.
Sounds like Hal’s programmers had never heard of the Three Laws of Robotics.
All in all, I found reading the book to be time well spent. Clarke has some beautiful passages about the sights and emotions of the astronauts on their way to Jupiter. And the role of the monolith is much more clear.