Creative people live in two worlds. One is the ordinary world which they share with others and in which they are not in any special way set apart fro… - Mark Kac

In the summer of 1930 my academic future, however, was not uppermost in my mind. I had been stricken by an acute attack of a disease which at regular intervals afflicts all mathematicians and, for that matter, all scientists: I became obsessed by a problem.

Independence is the central concept of probability theory and few would believe today that understanding what it meant was ever a problem.

As a mathematician Erdös is what in other fields is called a "natural". If a problem can be stated in terms he can understand, though it may belong to a field with which he is not familiar, he is as likely as, or even more likely than, the experts to find a solution.