 Now, you may say to yourself, well, what do other physicists today believe in? Well, I'll tell you what. My theory, in fact, the theory of most friends that I know, many of them Nobel Prize winners, in fact, believe in the multiverse. That is, in one universe, cats can be dead. In another universe, cats can be alive. And the universe splits in half. So we have a multiverse of universes with universes constantly splitting apart.