"Certainly," Stern agreed. "If the neuro-surgeon manages to touch precisely the right point in your brain while you're under a local anaesthetic, you'll start describing details of that room you had not realized you had seen. That's unconscious knowledge and it's much vaster than what you consciously acquire. Still though, you find that, even with this additional description, you've only covered a small percentage of the facts about that room. Now, if you're permitted to look into such a mystery room for, say, five minutes, you have a chance to move your eyes from point to point, to become aware of more things--and the neuro-surgeon's work will show your unconscious knowledge has also grown from longer viewing. Conscious and unconscious knowledge feed each other." "I can just barely follow you now," Linder protested. "This is getting awfully complicated." "Because we're dealing with an awfully complicated--and important--phenomenon. I'll get to the big point in just a moment but, first, one more case--a little simpler to follow, I hope. You enter a well-lighted room. In one corner two men are seated, playing chess. In another corner two men are repairing a machine. When you look at the chess players the machine repairers are barely visible in the corner of your eye. If you concentrate on the chess situation, you learn close to nothing about the repair work. And when you concentrate on the repair work the chess game fades out." "So what?" Linder demanded. "You merely move your eyes back and forth and follow both things if you want to!" "Exactly the point I was hoping to make, sir. This constant moving back and forth gives us the impression that our conscious attention is on two things at the very same time. Actually, though, it's only one thing at a time. Now, imagine you lose interest in both situations while a radio starts playing some music. A second radio comes in with other music. By shifting attention back and forth you may manage to identify both but you're really not hearing either one very well. And imagine what would happen if a third stream of music started up at the same time!" "That's right, you can only consciously follow one thing at a time," Crawford nodded. His eyes widened with horror. "They don't think that way at all! They were listening at the spaceport to musics and they see all these different things happening on the screen at the same time and follow it, don't they?" "Which gives them the capacity to learn anything at tremendous speed," said Stern. "Take manually driving a ground vehicle. We learn one operation until we can do it automatically, _un_thinkingly, then we learn another operation to the same point, reinforcing our first knowledge with the new acquirement, and so on. For all practical purposes _they_ could learn almost everything about such a matter at the same time, instantly!" Stern stared at the star chart on the Command Room's wall, and wondered whether the inward side of man was equally vast.