"Are you so sure?" Oktav could feel his questioning thought hang in the dark, like a great black bubble, coercing attention. "What if the botched worlds still live? What if, in thinking to obliterate them, you have merely put them beyond the reach of your observation, cut them loose from the main-trunk time-stream, set them adrift in the oceans of eternity? I've told you that you ought to visit the world more often in the flesh. You'd find out that your beloved main-trunkers are becoming conscious of a shadowy, overhanging danger, that they're uncovering evidences of an infiltration, a silent and mystery-shrouded invasion across mental boundaries. Here and there in your main-trunk world, minds are being displaced by minds from somewhere else. What if that invasion comes from one of the botched worlds--say from one of the worlds of the last trifurcation? That split occurred so recently that the alternate worlds would still contain many duplicate individuals, and between duplicate individuals there may be subtle bonds that reach even across the intertime void--on your admission, time-splits are never at first complete, and there may be unchanging _shared_ deeps in the subconscious minds of duplicate individuals, opening the way for forced interchanges of consciousness. What if the botched worlds have continued to develop in the everlasting dark, outside the range of your knowledge, spawning who knows what abnormalities and horrors, like mutant monsters confined in caves? What if, with a tortured genius resulting from their misery, they've discovered things about time that even you do not know? What if they're out there--waiting, watching, devoured by resentment, preparing to leap upon your pet?" Oktav paused and probed the darkness. Faint, but unmistakable, came the pulse of fear. He had shaken their complacency all right--but not to his advantage. "You're thinking nonsense," Prim thundered at him coldly, in thought-tones in which there was no longer any hope of mercy or reprieve. "It is laughable even to consider that we could be guilty of such a glaring error as you suggest. We know every crevice of space-time, every twig and leaflet. We are the masters of the Probability Engine."