Multiverses and the Inverse Gambler’s Fallacy

Continuing the discussion from Our Improbable Existence Is No Evidence for a Multiverse:

Steven Novella responds to Goff’s Our Improbable Existence Is No Evidence for a Multiverse.

I was intrigued by an article in Scientific American by philosopher, Philip Goff, mainly because I disagree with his ultimate conclusion. He makes a very cogent logical argument, but I am having trouble with one piece of it.

The notion that this just happened by chance, and that we are incredibly lucky to exist, is not satisfying. What are some possible explanations for this highly improbable fact? One is that some powerful being (i.e. God) made the universe with these precise values so that complex life could exist. This does not solve the problem, however, it just pushes back the mystery one step – for where did God come from? I also reject this answer as an obvious “god of the gaps” argument – filling in an unknown by invoking, essentially, magic. It gets us nowhere. Another possible answer is that there is some underlying reason for the laws of physics, a metalaw, that determines that these constants must have these values. We don’t know what this could be, but at least this is something to investigate.

One solution that many scientists have found compelling is the multiverse solution – perhaps there are an infinite (or at least really big number) of universes in a grand multiverse – so many that even if the constants of each universe are determined at random, by chance alone some of them will have the values necessary for complex life. Obvious we must live in a universe with these laws, and nothing can observe universes with laws incompatible with sentience. Problem solved.

So I think we are left with two possibilities. One is that the laws are not determined at random, and there is some reason in the deeper laws of physics for why they are what they are. The second is the multiverse hypothesis – that we may have won the cosmic lottery, but there are so many universes it is highly probable at least one universe would win. We don’t need to explain why our universe won, only that some universe would win (otherwise that’s the lottery fallacy).

I acknowledge that I could be wrong in all this, and that serious thinkers clearly disagree. But sometimes statistics and logic can be extremely counterintuitive and even experts make mistakes (including me). So if you think I made an error somewhere, please point it out. Either way this should be a good learning experience.


@sfmatheson, seems to be a pretty serious discussion about design. Is it science? I’m not sure, and I’m not sure it matters.

I’m surprised no one has discussed the “weak anthropic principle” though. The idea is that any observations we make of the universe are conditioned on our existence. So to say that the universe is improbably consistent with life as we know it, misses something important. In fact, given the premise that we exist, we expect to observe a universe with fine-tuning constants compatible with our existence.

Perhaps this shifts the problem about why the universe is as we find it to another place…why are we the way we find ourselves? Why do we exist?

I suppose we know we exist, but we cannot really be sure why we do, can we?

Then there is the option that I personally favour: Life, or something equally improbable and noteworthy, may be likely to arise in any possible universe. However, once you change the basic physical parameters of a universe the methods we have developed to understand OUR universe no longer apply. So we have no way of predicting what can or cannot arise in a different universe.

The belief that a universe capable of giving rise to life, or something like life, is highly improbable is just an intuition that is not based on sound reasoning.

A little off-topic as this is more of a cosmological argument, but to me, a multiverse where all possibilities are realized seems to itself ask out for a deeper explanation for its existence, perhaps even more so than a single universe with just a one set of laws.


No, it is philosophy.

That’s my normal response, but I chose not to bring it up earlier.

The weak anthropic principle explains everything that needs to be explained. But I suppose that’s a bit backward. The WAP doesn’t answer any of the issues that people raise. But it does make clear that no answer is needed. From the WAP, we can see that there isn’t anything that actually needs to be explained.

That’s right. It’s roughly the same question as “Why is there something rather than nothing?” We cannot answer such questions. The existence of such unanswerable questions, is why I am an agnostic rather than an atheist.

Yes, I agree.

I agree with that, too.

The multiverse idea might make for a good mathematical model for quantum physics. But I cannot see any reason to assume that it is other than a useful mathematical fiction.


I tend to think of cosmological origins as distinct from design, even though it is true that fine tuning and anthropic principle-related stuff does eventually touch design. And certainly it is coherent for someone to think of fine tuning as “design.” But for me, the kind of design that we see in biology requires explanation that is conceptually different from cosmological origins.

I don’t think it matters but for me this is clearly science, insofar as the questions and proposed answers are empirical and “natural.” That’s all I need, but I totally understand that there are various other definitions of “science” that would say this is “philosophy.” Not a meaningful distinction to me in any case.


There are two common responses to the fine-tuning argument not so far considered here:

  1. There are a number of publications concluding that a much broader range of physical constants would allow for life (actually, stars that last for billions of years) than some have supposed.

  2. The range of possible physical constant values is unknown, even as a rough estimate, so assuming any particular distribution, as is needed to calculate the improbabiity of the values of our universe, is impossible.


Oh, and it shouldn’t need to be said that any fine-tuning calculation that requires time-travelling crustaceans is suitable only for practising peacefulness in reply.

Something else that’s rarely mentioned is that life is fine-tuned for the universe, e.g. eyes detect light at frequencies that are not blocked by the atmosphere. So including a transparent atmosphere in the fine-tuning calculations overstates the case, because a different atmosphere would lead to different eyes. Fine tuning has to account for any form of life, not just the form we have.

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I disagree with what I perceive as the gist of this comment, that the fact that the atmosphere is largely transparent in the visibly region is no big deal, because if there were a different transparency “window” our eyes would simply have evolved differently. It is not, IMO, so simple. If the atmosphere were not transparent to visible light, evolution would have had to make a Sophie’s choice between eyes that were sensitive near the peak of the Sun’s blackbody spectrum and a non-overlapping transparency window. As it turns out, evolution did not have to make that choice as the two fortuitously coincide.

If I misconstrued your comment, I apologize.

On the other hand, this is not really part of the cosmological fine-tuning argument, which really is related to the ability of the universe to synthesize heavy elements. This is more related to the more local “privileged planet” type argument.

Strongly agree. Without knowing the distribution of possible values, probability statements are meaningless.

We might refine that to "any life form capable of asking this question about Fine Tuning.


Fine Tuning should be divorced from any probability argument. It is simply the claim (which needs to be evaluated) that any slight excursion from our set of constants results in an uninhabitable universe for any kind of life because heavy elements would not be created. If it’s true, it’s true whether the constants are improbable or required by some unknown theory of everything.


heavy elements are necessary for our kind of life. How do you know they are necessary for any kind of life?

This is one of those debates that won’t be settled anytime soon, as to go any further towards answering your question at the very least requires defining life. Only when you’ve done that can you proceed to try to answer whether there are interesting forms of physics and chemistry between lighter elements that would meet the definition of life.

Now of course, all of this is still contingent on the idea of adjusting the values of the fundamental constants of physics as we know it, such as the strength of electromagnetism, or the speed of light. What is never discussed is the possibility of an entirely different set of fundamental forces. Nobody actually really knows the range of interesting physics that allow for something we could call life.

Because you can’t make anything out of the base products of the Big Bang: Hydrogen and Helium. You need synthesized heavy elements to have complex chemistry and to create large molecules that can store information. This is not controversial.

I would disagree with that. “Fine-tuning” has a meaning. It requires that the values of constants would have been able to vary within some range. It’s also required in order for “slight excursion” to mean anything.

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I believe that is wrong. Fine tuning (if it is real) can be thought of this way. The constants form a multi-dimensional parameter space. We are in a region of that parameter space that results in habitability, and that region appears to be surprisingly small. If we take a small step (again, if it’s real) in any direction we find ourselves in an uninhabitable region. There might be many other disconnected regions of this parameter space that result in habitable universes, and they might even be large regions. But our particular region appears to be small.

Fine tuning is about the sensitivity of habitability to changes in the constants of our universe, nothing else. It is not about probability.

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The region and any step can be surprisingly small only by comparison to some assumed distribution of possibility. And you have no reason to assume the extent of any of the dimensions of your parameter space. “Small” is meaningless by itself, and you can have no basis for a standard of comparison.

Further, there are a number of publications exploring assumed parameter spaces that find results in variance with your claims.

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No, it’s not. But while complex chemistry and stored information are necessary for terran life, they aren’t defining characteristics of life. Again, how do you know that heavy elements are necessary for any kind of life?

Can you elaborate on what the sun’s black body spectrum is and how it relates to the transparency of the atmosphere to visible light?