Raiders of the lost purpose (4): On the multiverse and the South-Atlantic Principle

By Jesús Zamora Bonilla April 10, 2024 0 comments Print

I will close this series by commenting on the most conspicuous element of the contemporary debate about whether science points towards the existence of some kind of ‘cosmic purpose’: the possibility that the universe we observe is only a vanishingly small part of a mega-infinity of worlds – the multiverse, and more specifically, the inflationary multiverse. If there is an ‘elephant in the room’ for advocates of cosmic purpose, is the panic they feel when confronting the multiverse idea, and the preposterous efforts they make in order to try to persuade you that “multiverse is not science, but metaphysics” (to which one can respond that, well, perhaps it is true that the thesis that there are other ‘universes’ beyond this one is empirically untestable -which I don’t think it unavoidably is, by the way-, but it is funny that this particular objection is advanced by people believing in cosmic or divine superintelligences, that no one can even imagine how the hell do they physically work to do what they are supposed to do, something that, to say the least, multiverse theories do easily fulfil).

To a certain extent, it is logical that cosmic purposivists get very nervous when considering the multiverse idea, for it is the most robust alternative on the market to their favourite ‘explanation’ of the existence of an apparently ‘fine-tuned’ universe: if there were an infinity of different worlds, and especially if they might have an infinite variety of different physical laws, it wouldn’t be a surprise that some of them are hospitable to life, and so, our existence will be just a matter of luck, in a similar way as how your having been born in a particular place and time, within a family of such and such social features, doesn’t demand a cosmic-purposeful explanation. Philip Goff, the protagonist of our last entry, devotes a big effort to trying to show that the multiverse explanation is ‘fallacious’; in particular, he argues that this explanation commits the so called ‘inverse gambler’s fallacy’: if you enter a casino, and the first thing you observe is someone getting five of a kind ten times in a row in a game of poker, it would be fallacious to conclude something like “in this casino there must be an astronomical number of gamblers, so that the chance of someone getting such an unlikely hand of cards is close to one hundred percent” (in fact, in a scenario like this one, we know that the most plausible explanation would be, of course, that someone is doing some trick ‘on purpose’, not the least because we empirically know that there are no astronomically sized casinos, but there are lots of tricky people).

What Goff chooses to ignore is that, in the cosmic fine-tuning scenario, we have equally zero evidence of the existence of ‘cosmic cheating croupiers’, I mean, zero evidence beyond the very same fact purposivists attempt to explain -i.e., fine-tuning-, and hence their explanation only serves to explain the only fact they invented their hypothesis to explain, to begin with, which is the very definition of an ad hoc hypothesis. And furthermore, in the case of fine-tuning, we just have no piece of empirical knowledge analogous to the one that makes ludicrous to conjecture an infinitely sized casino (I mean: an infinity of universes to which our own universe belongs is not physically implausible a priori, in the same way as a Borgesian infinite casino would be within our own universe). For someone who so proudly claims to ‘have taken the sacred vow to follow the evidence wherever it leads’ (Goff’s own words), and who bases his reasoning in something he refers to as ‘the Requirement of Total Evidence’, any reference to these two pieces of missed evidence (or of ‘meta-evidence’: evidence about what is the evidence we have or do not have) is notoriously absent.

More serious mistakes

But critics of the multiverse explanation commit, in my opinion, three still more serious mistakes. In the first place, they choose to systematically ignore the fact that the existence of a multiverse is not an independent conjecture, just feigned to explain fine-tuning, but a logical consequence of other physical theories that were conceived to explain some other aspects of our observable universe (I refer, obviously, to the theory of cosmic inflation). In fact, if there were some other means of testing the existence of those other ‘bubble universes’ (which is not totally inconceivable), we would call this logical consequence a ‘prediction’. Hence, the more and more empirical or theoretical evidence accumulates in favour of some model of cosmic inflation which happens to have as a mathematical consequence the existence of an incredibly large number of bubble universes (and as no additional evidence continues to exist for a cosmic croupier and for Its possible mechanisms of action), the more and more the balance of total evidence will be inclined towards a multiverse explanation of fine-tuning.

In the second place, purposivists oscillate between arguing against the multiverse hypothesis by telling that ‘it is not proved enough’, and by telling that ‘it is not even scientific’. Obviously, it cannot be both ways, and the previous point makes it clear that, if any, it would be the case that the multiverse is by now just a scientific conjecture, not a scientific fact, but a legitimate scientific conjecture it undoubtedly is. This anxious endeavour for eliminating the multiverse idea as a legitimate player in the cosmic explanation game reveals a fear to the fact that, to have a significant role in the debate about whether there is a cosmic purpose, the multiverse conjecture does not need to be ‘scientifically proved’: its mere existence as just a scientific possibility immediately allows to block the conclusion that ‘science proves that there is a cosmic purpose’. We don’t need to prove that there is a multiverse in order to show that the existence of a cosmic designer cannot be taken as demonstrated; we just need to show that it is possible that there is a multiverse.

In the third and last place, as Sabine Hossenfelder has recently underlined, fine-tuners are too much mesmerized by the apparent ‘implausibility’ of the precise values of the physical constants. The truth is that, in order to reach any conclusion about how probable or improbable something is (for example, how probable it really is that the values of the fundamental physical constants are the ones they are), we have no choice but to start from some premise about the underlying statistical distribution of the physically possible values, and, hence, just assuming that all logically conceivable values have exactly the same physical probability is a conjecture as unfounded as any other (as it is the virtus propositiva conjecture according to which the values that most easily allowed the existence of complex life -and of ‘good things’ in general- had an intrinsically higher probability of being physically real, which is, after all, a what purposivism reduces to). We must accept that we don’t have the foggiest idea of what it was the empirically real statistical distribution from which the values of physical constant were determined, and hence all arguments merely based on the ‘implausibility’ of those values are intrinsically question-begging. And, of course, once we have some educated idea about what the physical values could be, we should apply to it some physically plausible conjecture about how the selection of the real values may have proceeded (something that, obviously, inflationary cosmologies provide, whereas cosmic purpose theories do not).

Let me illuminate this last point with a geographical example. Imagine that, when the contour of the continents was finally drawn with enough rigour around the 16^th and 17^th centuries, people had marvelled at the fact that the Atlantic coasts of Africa and South America fitted so perfectly as they actually do. Some wigged philosophe, as inventive as clever, might have produced an argument along these lines: “The precision with which the African and South American coastlines are finely tuned to each other proves that the map of the world must have to be drawn by an Intelligent Supernatural Designer; for, in the first place, it is extremely unlikely that the two lines are so remarkably similar, taking into account the infinite number of possible forms the coasts might have; and in the second place, we know there is no possible physical mechanism of transferring the information about the shape of one coast across the thousands of miles of ocean separating it from the other coast”. No more comments needed.

The multiverse as an inescapable logical conclusion

However, I do not resist the temptation of finishing the series with an argument showing that, if the fine-tuning of the universe were due to the existence of an omnipotent god, or at least of a Goffian cosmic mind, then the existence of a multiverse like the one entailed by the theory of eternal inflation would also be an inescapable logical conclusion. The purposivists’ fundamental premise is that the reason why the universe is as it is, is because of the purpose of maximising goodness, or something like that. But in our own universe, Mozart died at 36, what prevented the existence of many masterpieces that he would certainly have composed if he had lived twenty, thirty or forty more years. In a multiverse, there are surely innumerable bubble worlds that had been equal to our own’s till 1790-91, but in which Wolfgang Amadeus Mozart would have lived until well into the 19^th century, composing many of those here-and-now-inexistent musical works. Hence, if Mozart’s mature music is amongst the things almost anyone would count as ‘intrinsically good’, a benevolent (and powerful enough) cosmic mind should have preferred to create an astronomical number of universes, to allow that as many of those master pieces as possible were composed in at least some of them.