A Story about Paul Erdos and Science
This is one of my favorites anecdotes. Here Robert J. Aumann remembers one seminar by the always eloquent Paul Erdos. Even what seems to be a stupid joke from Erdos contains a deep thought:
“I vividly remember an afternoon ten or fifteen years ago when Paul Erdos, on one of his many visits to Jerusalem, was delivering a lecture at the mathematics colloquium. Though his mathematical powers were (and are) still extraordinary, he started by saying that he was now old and exhausted (”Zaken Vetashush”), and that little could be expected of him. Of course we all protested. But Erdos insisted, and finally stated flatly that he could prove that he was no less than 2 billion years old. In his childhood the earth had been 2 billion years old; now it was 4 billion years old; the conclusion about his age was inescapable.
Like many good jokes, Erdos’s has a serious kernel. In the 1920s, the model that best fitted the known observations and existing theory was a 2-billion-year-old earth. By the 1970s, radioactive dating had been discovered, our ways of thought had changed in many ways, and the 4-billion-year model fitted much better. Evidence that had seemed strong and convincing 50 years ago gave way to stronger and more convincing evidence in a different direction; the older evidence had to be, and was, explained away. It would be foolhardy to think that the process has ended here, that no new evidence will be discovered, that the earth is truly 4 billion years old. It seems much more likely that in the course of time we will change our minds—or rather our model—again and again; indeed, the end of the process is not in sight. Why say that we were ”wrong” then, that we have discovered the errors of our ways and are ”right” now? It seems much more apt to say that when Erdos was a child, 2 billion years was right, and now 4 billion years is right. Each of these two models is the one that best fits, or organizes, or ties together, the observations available at its time, and the theories current at its time.”
-Robert J. Aumann
