"Right. It is a matter of capacity. The brain is built to exceed the present demand, Andy. When it is needed, it will be available. Nature expects that the brain will be called on, one hundred percent, and she intends to keep increasing that availability as it is needed. But it takes millions of years to develop and evolve something as intricate as brain-material, and nature does not intend that you and I catch up with her and find her adaptive ultimate inadequate to proceed because of her lack of foresight. The necessities of brain material have far exceeded her ability to evolve it, up to the present time. You're using infinitely greater proportions of your brain than your ancestors. Suppose that they had been running at full capability? You'd be limited; at the top of your capability to progress. "So, Andrew, you're running on one tenth of your brain all because no real thinking can come out of a full brain. The fill will increase, with evolution and science, to high percentages, but will never reach saturation. Saturation, I believe, might be dangerous." "Sounds plausible," admitted Andrew. "It is true," said Gerd. "And now before you drive yourself mad by thinking in circles, come and have a good time." "No, I've just thought of something important. Your explanation gave me the impetus to think it out. Lenore, do you mind if I leave for an hour?" "I'd better go along--" "Please do not," objected Gerd. "Andy, I'll see that Lenore is properly entertained in your absence. May I?" Andrew nodded, and Lenore smiled brightly. "I'll be in excellent company," she said. "The best," agreed Andrew. "Don't forget that Gaya is here, too." "This is an evening of pleasure," said Gerd. "One, I should not deny Gaya her admiration nor her friends the opportunity of being with her. Two, Gaya and I understand one another perfectly." "Look, Gerd, I was fooling with Lenore. No one has any illusions about either you or Gaya, or fears, or doubts, or worries. If you'll keep Lenore from being lonely while I'm gone, I'll be more than grateful. See you in an hour." "Fair enough." * * * * * Andrew drove his flier at almost peak power all the way to Gene's home and dropped in on the roof with a sharp landing. He raced inside and found Gene working over a bread-board layout of an amplifier for the thought frequencies. He told Gene about Rayne's speech and waited for an answer. "What did you expect?" asked Gene. "The answer?" "No, but I hoped to catch him." "In catching anything, Andy, you should first know more than your rabbit." "You do not believe it?" "Nope." Gene handed the editor a sheet of paper. "Follow that?" Andrew started down the listed equations and stopped after the fourth. "Way ahead of me. How did you derive this term here?" "By deduction." "Guesswork?" "Deduction. It can be nothing else." "But knowing that is like establishing the validity of a negative result."