"Huh?"

"Look here," proceeded van Manderpootz. "It is obvious that the world I see is entirely different from the one in which you live. It is equally obvious that a strictly religious man occupies a different world than that of a materialist. The fortunate man lives in a happy world; the unfortunate man sees a world of misery. One man is happy with little, another is miserable with much. Each sees the world from his own point of view, which is the same as saying that each lives in his own world. Therefore there are as many worlds as there are points of view."

"But," I objected, "that theory is to disregard reality. Out of all the different points of view, there must be one that is right, and all the rest are wrong."

"One would think so," agreed the professor. "One would think that between the point of view of you, for instance, as contrasted with that of, say van Manderpootz, there would be small doubt as to which was correct. However, early in the twentieth century, Heisenberg enunciated his Principle of Uncertainty, which proved beyond argument that a completely accurate scientific picture of the world is quite impossible, that the law of cause and effect is merely a phase of the law of chance, that no infallible predictions can ever be made, and that what science used to call natural laws are really only descriptions of the way in which the human mind perceives nature. In other words, the character of the world depends entirely on the mind observing it, or, to return to my earlier statement, the point of view."

"But no one can ever really understand another person's point of view," I said. "It isn't fair to undermine the whole basis of science because you can't be sure that the color we both call red wouldn't look green to you if you could see it through my eyes."