“No,” he said, “that can’t be done. That is to say, one hasn’t a free will, even if the person acts that way. Neither can the other person think as he will, nor can I make him think what I want him to. But you can observe someone well, and then you can say fairly exactly what he thinks or feels; in this way you can generally predict what he will do the moment after. It’s quite simple, but people merely do not know it. Naturally it requires practice. To take an example from the butterfly world, there is a certain species of moth, of which the female is much rarer than the male. The moths reproduce like other animals, the male impregnates the female, who then lays the egg. Suppose you have in your possession a female of this type of moth--naturalists have often made the experiment--then the male moths fly in the night to this female, they even make a flight of several hours’ duration! Think of it! For many miles around all the males are conscious of the whereabouts of the only female moth in the district. People have tried to explain that, but it is not easy. Moths must have a sense of smell, or something like it, which allows them to pick up and follow an almost imperceptible scent, like a good hound. You understand? There are such things, nature is full of them, and no one can explain them. Now I draw the conclusion that if among this class of moths the females were as abundant as the males, then these latter would not have such a refined sense of smell! They have it simply because they have been trained like that. If an animal or a man concentrates his whole attention and his whole will-power on a certain thing then he attains it. That’s all. And it is just the same with what you have asked me. Observe a man sufficiently well, and you will know more about him than he does himself.” It lay on the tip of my tongue to mention the word “mind-reading,” and so to remind him of the scene with Kromer, now relegated to such a distant past. But the odd thing between us both was that neither he nor I ever made the slightest reference to the fact that several years ago he had intervened so decisively in my life. It was as if formerly there had been nothing between us, or as if each of us reckoned that the other had forgotten the affair. It even happened once or twice when we were together that we met Frank Kromer in the street, but we exchanged no look, neither did we speak of him. “But what has that got to do with will-power?” I asked. “You said there was no such thing as free will. And then you said one only had to concentrate one’s will on something to be able to attain one’s ends. That doesn’t agree! If I am not master of my will, then I can’t direct it here or there as I wish.”