Each Pyramid as it stood was a radio-astronomy observatory, powerful and accurate beyond the wildest dreams of Earthly radio-astronomers. From this start, they built instruments to aid their naked senses. They went into a kind of hibernation, reducing their activity to a bare trickle except for a small "crew" and headed for Earth. They had every reason to believe they would find more Components there, and they did.
Tropile was one of them. The only thing which set him apart from the others was that he was the most recent to be stockpiled.
The religion, or vice, or philosophy he practiced made it possible for him to be a Component. Meditation derived from Zen Buddhism was a windfall for the Pyramids, though, of course, they had no idea at all of what lay behind it and did not "care." They knew only that, at certain times, certain potential Components became Components which were no longer merely potential—which were, in fact, ripe for harvesting.
It was useful to them that the minds they cropped were utterly blank. It saved the trouble of blanking them.
Tropile had been harvested at the moment his inhibiting conscious mind had been cleared, for the Pyramids were not interested in him as an entity capable of will and conception. They used only the raw capacity of the human brain and its perceptors.
They used Rashevsky's Number, the gigantic, far more than astronomical expression that denoted the number of switching operations performable within the human brain. They used "subception," the phenomenon by which the reasoning mind, uninhibited by consciousness, reacts directly to stimuli—shortcutting the cerebral censor, avoiding the weighing of shall-I-or-shan't-I that precedes every conscious act.
The harvested minds were—Components.
It is not desirable that your bedroom wall switch have a mind of its own; if you turn the lights on, you want them on. So it was with the Pyramids.
A Component was needed in the industrial complex which transformed catabolism products into anabolism products.