Hal Finney writes: > What is the paradox here? Are you saying that our deduction that we > live in a level 1 multiverse (i.e. one which is infinitely large and > full of stars and planets much like our own) is possibly wrong? That > may be true but it doesn't strike me as a paradox. All of our > reasoning is potentially wrong; we may be delusional, we may be > misinterpreting our results, we may be unlucky and atypical (for > example, earthlike planets may be enormously less likely than we > imagine). The possibility of being wrong is fundamental to scientific > and philosophical inquiry. I don't see that this new source of > potential wrongness rises to the level of a paradox.

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The paradox consists of the fact that the theory of multiverses tells us that there must be infinite observers who experiment other physical laws. There is not only the possibility of being wrong, it is the model itself which proves to be wrong. In fact it tells us that there are infinite places and times in this multiverse where, if any people observe the world around them in the same way we are doing hic et nunc, they necessarly find another model to describe the universe. So the outcome of the model is that it must be wrong in infinite places and times, and the paradox is that we have proved that it is wrong, but we have been able to draw this conclusion because we have considered the hypothesis of applying the physical system itself. But if it was wrong, the conclusions would be wrong, too. > The problem with this reasoning is that there are many more observers > who see the laws of physics violated only rarely than those who see > them violated continually. Let's suppose that suddenly we start > observing a violation, like suddenly we get a 6 every time anyone > throws a dice. Now, looking forward, there are universes where that odd > behavior > continues forever, and universes where that behavior stops and we go > back to the normal laws of probability. The point is that the second > set of universes is overwhelmingly more numerous than the first. (If > you are concerned about comparing infinite universes, consider looking > at a large but finite volume of the universe, as the volume goes to > infinity.) > > So in fact we would be correct at every point to expect the normal laws > of physics to resume, because enormously more copies of ourselves will > find that to happen than those who find the violations to continue. I believe the point is that we think "the second set of universes is overwhelmingly more numerous than the first" because we live in THIS universe. But if we lived in another part of our multiverse we would think in a completely different way and no a priori principles can tell us when one is right. Federico Marulli