Leslie and Design

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John Leslie discusses a number of different angles on the traditional theistic Argument from Design; I wish to explore this matter in a similar but distinct way which may be revealing.

First, let us agree upon the following:

  1. There are an infinite number of logical ways that a universe can be conceived.

This is a fairly unremarkable claim; it only says that, if we were to play at world-creation, (here “we” can represent the role of either Chance or God or another), we could construct the Altogether using all sorts of different rules and entities, where probably the only limit would be logical contradiction. Perhaps there are other limits, and perhaps the varieties are not infinite but merely exceptionally great; this distinction is not too important.

Next, we must agree that:

  1. At least one way of conceiving the universe is actually real.

The point here is that we do live in a possible universe made manifest; at least one way that everything could be, actually is. The Anthropic Principle has things to say about this, but we are not there yet; let us agree merely that one universe does exist, which we will all grant so long as we are not skeptics.

Now we enter the realm of the contentious. The key matter amounts to this: are some of the logically possible universes (per #1) less likely than others? Namely, is the actual universe (#2) one of these? If some universes are in fact overwhelmingly unlikely, and we find that they are nevertheless real, then we have a situation we must explain either with additional considerations, or by simply granting astronomically good fortune.

Consider the following situations:

We can see that first case of each of the above pairs is actually identical in probability to the second case. The exact same circumstances played out. Why, then, do we call the latter cases improbable, whereas the former cases are either highly unremarkable or actually necessary?

The reason is because in the latter cases, we previously designated a particular state of affairs as desired or at least significant, and reality then worked out accordingly. It is equally likely that a six-sided die will land on a 4 as it will land on a 3, or a 6, or a 1, etc.; and we know for sure that it will land on one such number; therefore the only question is whether some number 1–6 will be shown when it lands, and the probability of this is essentially 1. However, if we previously designate the result 4 as unusual, the probability of this result becomes 1 in 6, a far less likely situation.

This all seems rather straightforward, but the important point is this: it is only by designating a particular state of affairs that the actual manifestation of that state becomes interesting (and potentially unlikely). And it is only prior to the manifestation that we can perform this act. After the die has landed on 4, it is no great feat to predict it will land on 4; it can no longer do otherwise.

The analogy being made here is between the divergent causal paths in the real world (where possible realities become an actual one—the criterion can be “chance,” or choices of free will, or whatever), and the distinct initial states that define a particular reality (determined by either chance, or God, or whatever), since these both treat with the relationship between possible and actual worlds. Consider the following depiction of the universe, where dotted lines represent possible realities—diverging where the cards are dealt differently, the die lands on 4 or 6, you take the train or you don’t, etc.

Now, let us “play time forward,” let things unfold, and at the end of all things, examine what actually took place—we drew a straight, rolled a 4, took the train, etc. The solid line represents actual reality.

We can consider that, viewed at time t0, the actual state of affairs that unfolds here is very unlikely, even infinitely so, when viewed against the alternatives. However, viewed in retrospect at time t, this is not the case at all; obviously one such line would have to be actualized. The presence, or abundance, of the other “possible” paths has no bearing upon this. Why then do we consider the one true path to be “unlikely” when viewed ante rem? Simply for the previously-discussed reason: now that we have “selected” this particular path ahead of time—for instance, a world where intelligent life evolves—the odds of it turning out to be the real one, made apparent at t, are seemingly quite small.

And yet, the actual state of things in the first two models, in fact, identical. Consider a third scenario:

Here, one particular universe is actual, and none other is possible. The way things happened is the only way things could have happened; there are no counter-factuals or alternate timelines.

Now, we can hold one of two premises to be possible here:

  1. a. Many actual worlds exist, although only one of them is accessible to us.
    b. Only one world exists, although others are conceivable.

The first is illustrated by the first two illustrations; the second is shown in the third. So what? What is striking is that both possibilities are identical in terms of accessible results. In both cases, the solid line, or the reality as apparent to us, is the same. What is more, it is clear that whether we view these states at t0 or t is also irrelevant to the timeline. No matter what, only one reality is and will be made real. Perhaps others were possible, and perhaps others are even real to other viewers, but none of this makes any difference.

How, then, can we reconcile the seeming difference between t0 (when rolling a 4 today is unlikely) and t (when drawing a 4 on that day was certain)? The answer is that there is no difference. The only difference is in how we perceive these things, which is interesting, and relevant insofar as our imperfect information about how things will play out is significant in our lives, but it has no bearing on the physical and metaphysical reality. So the correct third premise is:

  1. Only one actual world exists, as far as we are concerned.

Could things have been otherwise? No, in fact, things could not have been otherwise; things can only be one way. Even if other worlds exist where things are different, there too, things can only be one way. Positing true “many worlds” merely multiplies things without changing them, for even in other worlds there will not be multiple alternatives available. There is therefore no sense in asking whether other possible worlds were more or less likely to be real than the one we inhabit; the one we inhabit is inevitable, is 100% likely.

The only question is whether the particular world we are in corresponds to a particular sort, a criterion we are applying externally—that is, whether it is a world where intelligent life exists. And here the Anthropic Principle stands correct, although mute: this is obviously a world where intelligent life exists, because in a cogito sort of way we are here to ask the question. But this observation says nothing as to either divine intervention or the lack thereof.