Last time we introduced the notion of a multiverse in which every possible universe exists--the universe in which I am a famous rock star, the one in which I am a bestselling author, and many others. I said that I did not believe those universes exist--but admitted that that was an emotional reaction. I have a more logical reason, though, for my disbelief.
One of the things that sometimes happens to people is we "go off the deep end". Someone who has been seemingly normal his entire life without any advance warning shoots up an elementary school, or rapes a co-worker, or robs a bank. We would all like to believe that it could not happen to us, but anyone who has seen the film Falling Down should recognize that quite a bit of our self-composure is simply that we have not been pushed past our limits. Any one of us could "snap" at any moment. It could be this moment; it could be tomorrow morning. There are probably a thousand things we could do when that happened, all of them bad, most of them newsworthy.
If we assume that all possible universes exist, then there is a universe in which you snap right now, and another universe in which you snap right now, and another in which--you get the picture. Not only that, there is a universe in which you and I both go at the same time, another in which you go first and then I go, and another the other way around; and this is true for everyone in the world. There is, in fact, a universe in which all of us "lose it" right now, for every "right now". It certainly means that of billions of people on Earth, if only thousands are doing so on any given second, or even on any given day, that is a very small fraction of the total. There are worlds that are very bad, because everyone is going crazy right now. By this theory they must exist.
In fact, by this theory, we cannot be certain that our world is not going to descend into such a nightmare any second now. Yet despite the possibility that anyone might go crazy at any moment, and that by simple random chance there ought to be universes in which vast numbers of people do so simultaneously with no connection to each other, it never happens. We have random acts of violence that are unexpected, but we do not have them as frequently or at the saturation level that must be true in many universes in order for all possible universes to exist. We have wars and riots, but these events occur because of the connections between the people involved.
That suggests that the universe in which we find ourselves is really extremely improbable. It might have happened a moment ago; it might have happened this morning, or yesterday, or last week. It has never happened. Yet if this theory of the multiverse is true, it might happen today, tonight, tomorrow, next week, at any moment when we do not expect it. The entire human population could go crazy all at once; even if it were limited to one tenth of one percent of individuals randomly scattered throughout the world, it would be a devastating event.
We might propose all kinds of reasons why it does not happen, but the fact remains that those universes must be realities if the theory is true, and it must be the case that at this moment the universe has once again splintered into decillions of diverging histories, in quadrillions of which vast numbers of people have gone over the edge and begun some type of violent spree. Why have you and I never been in any of those universes? There must be versions of us who are; we never seem to be those versions.
I would like to believe that this would not happen to me, that because of my character and the work of God in my life I would not become one of those violent statistics. You probably believe that of yourself as well. If we are correct, though, then not all possible universes are real, and not every choice you make creates a universe in which you chose otherwise.
There might be parallel dimensions, but there are not divergent histories of the sort suggested by the advocates of Schrödinger's Cat. The demonstration that there is some kind of multiverse is not a demonstration of histories parallel to our own, but merely of facets of the universe not spatially connected to us in a way we can perceive. That is more than I know, really; but I know that there is not a version of me in another universe that just blew up the mall.