"You're overwhelmed by the detail work," Groating smiled, "but not by the lack of logic. It is possible to obtain all possible data on the orchard in question and integrate the factors into an accurate prophecy not only as to the theft, but as to the time and place of theft. Apply this example to our own Universe and you can understand the working of the Prognosis Building. We have eight floors of data analyzers. The sifted factors are fed into the Integrators and--presto, prophecy!" I said: "Presto, my poor head!" "You'll get used to it in time." I said: "The pictures?" Groating said: "The solution of a mathematical problem can take any one of a number of forms. For Prognosis we have naturally selected a picturization of the events themselves. Any major step in government that is contemplated is prepared in data form and fed into the Integrator. The effect of that step on the world line is observed. If it is beneficial, we take that step; if not, we abandon it and search for another--" I said: "And the pictures I saw this afternoon?" Groating sobered. He said: "Up until today, Mr. Carmichael, we have not been able to integrate closer to the present than a week in the future--or deeper into the future than a few hundred years. Wiggon's new data technique has enabled us to push to the end of our existence, and it is perilously close. You saw the obliteration of our Universe take place less than a thousand years from now. This is something we must prevent at once." "Why all the excitement? Surely something will happen during the next ten centuries to avoid it." "What will happen?" Groating shook his head. "I don't think you understand our problem. On the one hand you have the theory of our society. Stability. You yourself have quoted the Credo. A society which must maintain its Stability at the price of instability is Chaos. Keep that in mind. On the other hand we cannot wait while our existence progresses rapidly toward extinction. The closer it draws to that point, the more violent the change will have to be to alter it. "Think of the progress of a snowball that starts at the top of a mountain and rolls down the slopes, growing in bulk until it smashes an entire house at the bottom. The mere push of a finger is sufficient to alter its future when it starts--a push of a finger will save a house. But if you wait until the snowball gathers momentum you will need violent efforts to throw the tons of snow off the course." I said: "Those pictures I saw were the snowball hitting our house. You want to start pushing the finger now--" Groating nodded. "Our problem now is to sift the billions of factors stored in the Prog Building and discover which of them is that tiny snowball." * * * * * The controller, who had been silent in a state of wild suppression all the while, suddenly spoke up. "I tell you it's impossible, Mr. Groating. How can you dig the one significant factor out of all those billions?"