What Wigner has done was to find out the results, the consequences of the symmetry in the case of atoms and molecules. Hydrogen atom. One might guess the electron is somehow spherically distributed around the atom. And so it was, incidentally, in one particular state, the lower state of the hydrogen atom. But there were cases, most cases, where the symmetry was changed by the way the electron moved. And that had consequences for the behavior of the quantum states of the hydrogen atom, or any atom of the kind- any other atom of the kind. It has a consequence that the same energy, several ways belonged in which the electron could moved- could move. Indeed, by several we would mean infinitely many. If the electron would move on an ellipse around the- around the nucleus. No, you see, in classical theory, the ellipse could be in every direction, infinitely many states of the same energy. In quantum mechanics, there were only a few. And these few had to be in- interrelated in a very specific way which the mathematicians had already saw - had already studied - decades earlier. And this kind of a study was called group theory. I was asked to report on it. I cannot claim that I reported on it with full understanding. I can claim that I understood some of it. And I can say that when I reported on my semi-understanding, and that the questions that Heisenberg asked made me understand it very much better. It was a nice experience.