to the left or to the right; it does not grow both ways. When the 'time' comes for the decision to be made, the forces that work toward causing that decision have been in force for some duration and the tree takes the most logical move; therefore only one future ensues. Even in the decision of a possible dictator of all humanity, the decisions he makes are dependent upon his past experience. Grand Chance is not a matter of tossing dice; men have a free will, Ackerman. Yet their lives are fairly well cast ahead of time by the course of their pasts. The formula that caused World War II to grow out of World War I was evident enough to prevent World War III; yet in no way could Adolph Hitler have been averted because he rose out of a situation already created." "It still sounds like predestination—and the futility of all effort." "Not so. You are a free will, Lester—yet your actions are conditioned by your past. By 'free will', I mean you have a choice of alternatives within the frame of conditions around you. The only ones whose actions are not dictated by solid experience are the insane. And they, even by the Ancients, were termed 'Unpredictable'." Ackerman nodded. Once you knew a man, you could make a fair prediction of how he would react to a given set of conditions, starting no major alterations in his motives and view points, etc. Perhaps if you knew him very well, your prediction would be better. Les smiled grimly. No man knew another that well. In fact, he admitted silently, no man knew himself well enough to predict his own reaction to an entirely unprecedented situation! Outside, the terrible earth-glow had become intense. It was expanding like a misshapen balloon. Wispy clouds of high-energy were fingering out into space, followed shortly by the main mass as it dispersed. It was ten times the original diameter now, and increasing rapidly. "It will take days," said Blaine. "Of our accelerated 'time'. But you know the end-point." Ackerman knew. The end-point of this was a blank space in the solar system and a gradual re-establishment of the energy-distribution of the solar system to make up for the missing mass-energy and attraction of the destroyed earth. "What can I do?" he asked helplessly. "How did they hit the earth?"