I began by asking why things are as they are. Before returning to that question, we should ask how things are. There is much about our world that we have not discovered. And, just as there may be other worlds that are like ours, there may be worlds that are very different. It will help to distinguish two kinds of possibility. Cosmic possibilities cover everything that ever exists, and are the different ways that the whole of reality might be.
Only one such possibility can be actual, or the one that obtains. Local possibilities are the different ways that some part of reality, or local world, might be. If some local world exists, that leaves it open whether other worlds exist. One cosmic possibility is, roughly, that every possible local world exists.
This we can call the All Worlds Hypothesis. Another possibility, which might have obtained, is that nothing ever exists. This we can call the Null Possibility. In each of the remaining possibilities, the number of worlds that exist is between none and all.
There are countless of these possibilities, since there are countless combinations of particular possible local worlds. Of these different cosmic possibilities, one must obtain, and only one can obtain. So we have two questions: which obtains, and why? These questions are connected. If some possibility would be easier to explain, we have more reason to believe that this possibility obtains. This is how, rather than believing in only one Big Bang, we have more reason to believe in many.
Whether we believe in one or many, we have the question why any Big Bang has occurred. Though this question is hard, the occurrence of many Big Bangs is not more puzzling than the occurrence of only one.
Most kinds of thing, or event, have many instances. We also have the question why, in the Big Bang that produced our world, the initial conditions allowed for complexity and life. If there has been only one Big Bang, this fact is also hard to explain, since it is most unlikely that these conditions merely happened to be right. If, instead, there have been many Big Bangs, this fact is easy to explain, since it is like the fact that, among countless planets, there are some whose conditions allow for life.
Since belief in many Big Bangs leaves less that is unexplained, it is the better view. If some cosmic possibilities would be less puzzling than others, because their obtaining would leave less to be explained, is there some possibility whose obtaining would be in no way puzzling?
Consider first the Null Possibility, in which nothing ever exists. To imagine this possibility, it may help to suppose first, that all that ever existed was a single atom. We then imagine that even this atom never existed. But that is not so. When we imagine how things would have been if nothing had ever existed, what we should imagine away are such things as living beings, stars and atoms.
There would still have been various truths, such as the truth that there were no stars or atoms, or that 9 is divisible by 3. We can ask why these things would have been true. And such questions may have answers. Thus we can explain why, even if nothing had ever existed, 9 would still have been divisible by 3. There is no conceivable alternative. And we can explain why there would have been no such things as immaterial matter, or spherical cubes.
Such things are logically impossible. But why would nothing have existed? Why would there have been no stars or atoms, no philosophers or bluebell woods?
We should not claim that, if nothing had ever existed, there would have been nothing to be explained. But we can claim something less. Of all the global possibilities, the Null Possibility would have needed the least explanation. As Leibniz pointed out, it is much the simplest, and the least arbitrary.
And it is the easiest to understand. It can seem mysterious, for example, how things could exist without their existence having some cause, but there cannot be a causal explanation of why the whole Universe, or God, exists. The Null Possibility raises no such problem. If nothing had ever existed, that state of affairs would not have needed to be caused.
Reality, however, does not take its least puzzling form. In some way or other, a Universe has managed to exist. Consider next the All Worlds Hypothesis, in which every possible local world exists. Unlike the Null Possibility, this may be how things are. And it may be the next least puzzling possibility. This hypothesis is not the same as — though it includes — the Many Worlds Hypothesis. On that more cautious view, many other worlds have the same elements as our world, and the same fundamental laws, and differ only in such features as their constants and initial conditions.
The All Worlds Hypothesis covers every conceivable kind of world, and most of these other worlds would have very different elements and laws. If all these worlds exist, we can ask why they do. But, compared with most other cosmic possibilities, the All Worlds Hypothesis may leave less that is unexplained. With every other cosmic possibility, we have a further question. It may be objected that, even if all possible local worlds exist, that does not explain why our world is as it is.
But that is a mistake. If all these worlds exist, each world is as it is in the way in which each number is as it is. We cannot sensibly ask why 9 is 9. Nor should we ask why our world is the one it is: why it is this world.
Though the All Worlds Hypothesis avoids certain questions, it is not as simple, or un-arbitrary, as the Null Possibility. There may be no sharp distinction between worlds that are and are not possible. It is unclear what counts as a kind of world.
And, if there are infinitely many kinds, there is a choice between different kinds of infinity. Whichever cosmic possibility obtains, we can ask why it obtains. All that I have claimed so far is that, with some possibilities, this question would be less puzzling. Let us now ask: could this question have an answer? Might there be a theory that leaves nothing unexplained? It is sometimes claimed that God, or the Universe, make themselves exist.
But this cannot be true, since these entities cannot do anything unless they exist. On a more intelligible view, it is logically necessary that God, or the Universe, exist, since the claim that they might not have existed leads to a contradiction.
On such a view, though it may seem conceivable that there might never have been anything, that is not really logically possible. Some people even claim that there may be only one coherent cosmic possibility. Thus Einstein suggested that, if God created our world, he might have had no choice about which world to create. If such a view were true, everything might be explained. Reality might be the way it is because there was no conceivable alternative.
But, for reasons that have been often given, we can reject such views. Consider next a quite different view. Only one such possibility can be actual, or the one that obtains. Local possibilities are the different ways that some part of reality, or local world, might be. If some local world exists, that leaves it open whether other worlds exist. Why This? The local could refer to a part of reality—like a planet—and the cosmic to the whole of reality—the universe.
Alternatively, the local could refer to a particular universe, and the cosmic to all the universes or the multiverse. I favor the latter interpretation. Either way the cosmic possibilities are what is important. The cosmic possibilities range from every conceivable reality existing the all worlds possibility to no conceivable reality existing the null hypothesis.
But suppose that 58 worlds existed. This number has some special features, such as being the smallest number that is the sum of seven different primes. It may be just conceivable that this would be why 58 worlds existed; but it would be more reasonable to believe that the number that existed merely happened to be There are, I have claimed, some credible Selectors.
Reality might be some way because that way is the best, or the simplest, or the least arbitrary, or because its obtaining makes reality as full and varied as it could be, or because its fundamental laws are, in some way, as elegant as they could be. Presumably there are other such features, which I have overlooked. In claiming that there are credible Selectors, I am assuming that some cosmic and explanatory possibilities are more probable than others.
That assumption may be questioned. Judgments of probability, it may again be claimed, must be grounded on facts about our world, so such judgments cannot be applied either to how the whole of reality might be, or to how reality might be explained.
This objection is, I believe, unsound. When we choose between scientific theories, our judgments of their probability cannot rest only on predictions based on established facts and laws. We need such judgments in trying to decide what these facts and laws are. And we can justifiably make such judgments when considering different ways in which the whole of reality may be, or might have been.
Compare two such cosmic possibilities. In the first, there is a lifeless universe consisting only of some spherical iron stars, whose relative motion is as it would be in our world. In the second, things are the same, except that the stars move together in the patterns of a minuet, and they are shaped like either Queen Victoria or Cary Grant.
We would be right to claim that, of these two possibilities, the first is more likely to obtain. In making that claim, we would not mean that it is more likely that the first possibility obtains. Since this possibility is the existence of a lifeless universe, we know that it does not obtain. We would be claiming that this possibility is intrinsically more likely, or that, to put it roughly, it had a greater chance of being how reality is. If some possibility is more likely to obtain, that will often make it more likely that it obtains; but though one kind of likelihood supports the other, they are quite different.
Another objection may again seem relevant here. Of the countless cosmic possibilities, a few have special features, which I have called credible Selectors. If such a possibility obtains, we have a choice of two conclusions. Either reality, by an extreme coincidence, merely happens to have this feature, or — more plausibly — this feature is one of the Selectors.
It may be objected that, when I talk of an extreme coincidence, I must be assuming that these cosmic possibilities are all equally likely to obtain. But I have now rejected that assumption. And, if these possibilities are not equally likely, my reasoning may seem to be undermined. As before, that is not so. Suppose that, of the cosmic possibilities, those that have these special features are much more likely to obtain.
As this objection rightly claims, it would not then be amazing if such a possibility merely happened to obtain. But that does not undermine my reasoning, since it is another way of stating my conclusion. It is another way of saying that these features are Selectors. These remarks do show, however, that we should distinguish two ways in which some feature may be a Selector. Probabilistic Selectors make some cosmic possibility more likely to obtain, but leave it open whether it does obtain.
On any plausible view, there are some Selectors of this kind, since some ways for reality to be are intrinsically more likely than others. Thus, of our two imagined universes, the one consisting of spherical stars is intrinsically more likely than the one with stars that are shaped like Queen Victoria or Cary Grant.
Besides Probabilistic Selectors, there may also be one or more Effective Selectors. If some possibility has a certain feature, this fact may make this possibility, not merely intrinsically more likely, but the one that obtains. Thus, if simplicity had been the Effective Selector, that would have made it true that nothing ever existed. And, if maximality is the Effective Selector, as it may be, that is what makes reality as full as it could be.
When I talk of Selectors, these are the kind I mean. There are, then, various cosmic and explanatory possibilities. In trying to decide which of these obtain, we can in part appeal to facts about our world. Thus, from the mere fact that our world exists, we can deduce that the Null Possibility does not obtain.
And, since our world seems to contain pointless evils, we have reason to reject the Axiarchic View. Consider next the Brute Fact View, on which reality merely happens to be as it is. No facts about our world could refute this view. But some facts would make it less likely that this view is true. If reality is randomly selected, what we should expect to exist are many varied worlds, none of which had features that, in the range of possibilities, were at one extreme.
That is what we should expect because, in much the largest set of cosmic possibilities, that would be what exists. If our world has very special features, that would count against the Brute Fact View.
Return now to the question whether God exists. Compared with the uncaused existence of one or many complicated worlds, the hypothesis that God exists has been claimed to be simpler, and less arbitrary, and thus more likely to be true.
But this hypothesis is not simpler than the Brute Fact View. Rather, as I have just said, we should expect there to be many worlds, none with very special features. Ours may be the kind of world that, on the Brute Fact View, we should expect to observe. Similar remarks apply to the All Worlds Hypothesis. Few facts about our world could refute this view; but, if all possible local worlds exist, the likely character of our world is much the same as on the Brute Fact View.
That claim may seem surprising, given the difference between these two views. One view is about which cosmic possibility obtains, the other is about why the one that obtains obtains. And these views conflict, since, if we knew either to be true, we would have strong reason not to believe the other. If all possible worlds exist, that is most unlikely to be a brute fact. But, in their different ways, these views are both non-selective.
On neither view do certain worlds exist because they have certain special features. So, if either view is true, we should not expect our world to have such features. To that last claim, there is one exception. This is the feature with which we began: that our world allows for life. Though this feature is, in some ways, special, it is one that we cannot help observing. That restricts what we can infer from the fact that our world has this feature. Rather than claiming that being life-allowing is one of the Selectors, we can appeal to some version of the Many Worlds Hypothesis.
If there are many worlds, we would expect a few worlds to be life-allowing, and our world is bound to be one of these few. Consider next other kinds of special feature, ones that we are not bound to observe. Suppose we discover that our world has such a feature, and we ask whether that is no coincidence. It may again be said that, if there are many worlds, we would expect a few worlds to have this special feature. But that would not explain why that is true of our world. We could not claim — as with the feature of being life-allowing — that our world is bound to have this feature.
So the appeal to many worlds could not explain away the coincidence. Suppose, for example, that our world were very good, or were wholly law-governed, or had very simple natural laws.
Those facts would count against both of the unselective views: both the All Worlds Hypothesis and the Brute Fact View. It is true that, if all worlds exist or there are very many randomly selected worlds, we should expect a few worlds to be very good, or wholly law-governed, or to have very simple laws. He raises every possible objection to these propositions he brings about and exa If the universe exists in a way extremely special, this very specificity of it - the Selector, may explain its existence.
He raises every possible objection to these propositions he brings about and examins them in details. From refusing these objections he then incrementally make progress in his theoretical construction. The most sublime question - why there is anything rather than nothing at all, itself, however, has its special stance in philosophy for a reason.
When we try to get any grasp of it, even the most fundamental axioms of thoughts become rather powerless. Haim Gaifman wrote a comment to the second half of the essay on London Review of Books questioning Derek's notion of the need for explanation and, perhaps, what really does "special" mean? Came from an interview with Jim Holt about his book "Why does the world exist? He did not exaggerate in my opinion. However, even after reading this, my favourite answer to the sublime question by far remains to be the one given by Jim's supervisor Sidney Morgenbesser: "Oh, even if there was nothing, you still wouldn't be satisfied!
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