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The fermi paradox asks why we don't see more complex life in the universe if we exist? Essentially, it seems either would naturally develop in our universe, in which case it would be plentiful, or it is a fluke, in which case we probably wouldn't exist. The metaphor I've heard for the latter is that the chance of life forming in a universe with thermodynamic laws like ours is orders of magnitude less than a tornado going through a junkyard and assembling a 747 jet.

If, as I understand it, any time an a stochastic event occurs, it is represented in every possible form by different subsets of the collapse of the universal wave function, or more simply, everything that could follow from an action then occurs in a different 'branch', then doesn't that solve the Fermi paradox by essentially saying that in the majority of these 'branches' absolutely no life ever forms, but because life is extremely improbable but possible, it is likely that across all possible branches, you would see a few with life. Like if you ran a tornado through a junkyard grahams number of times, it would probably assemble a 747 in a few of those runs? This would mean that it is unlikely there are aliens in our 'branch', but there would almost certainly be other intelligent life in other branches, inaccessible to us.. though admittedly, we would have to look through a preposterously large number of branches devoid of life to find a single one with intelligent life.

Given this interpretation, wouldn't the many-worlds theory, if true, answer the question posed by the Fermi paradox?

EDIT: Response to commenter

The fundamental shift in logic changes from saying that: intelligent life is an event of x probability in a universe of y size, where x and y are unknown variables, to: intelligent life is an event of non zero x probability in a universe of arbitrary size, in which all possible sequences of events that have non zero probability are, at some point, "expressed" in the wave function (or in more concrete human terms: occur in a branch).

The whole point is that you DON'T need to explain why intelligent life is unlikely, you just need to say it has a non zero probability (which evidently, it does), and then many worlds fills in the gaps, because any non zero probability thing "happens" at some point in some branch. If the many worlds hypothesis is proven true, this would seem to have direct implications in that it may add credence to the idea that there is no universal tendency towards complex life, just an arbitrarily small chance of it occurring.

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  • $\begingroup$ No: the Fermi paradox stems from the fact that the evolution of life actually appears quite likely, and yet we seem to be the only life around. If your answer is just "life's actually unlikely but we got lucky", then you don't need to invoke the many world "interpretation" at all. You do need to explain WHY you think life is so unlikely, when on the face of things it seems probable. Personally I do think life is unlikely and Earth is one of the only places in the universe it could have occurred, but I have no hard calculation to support this. $\endgroup$ – Harry Wilson Aug 14 '20 at 14:16
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You do not need the many worlds interpretation of quantum mechanics to resolve the apparent tension between life possibly being very rare and us sitting here: all you need is a sufficiently big world - it does not have to be infinite, even.

The Fermi paradox is a bit deeper than "life is unlikely, yet here we are" (actually, it is intelligence rather than life). Rather, it is "there is a lot of places intelligence could be in the world, and multiplied with a reasonable probability we ought to see a lot of it". The problem here is the often implicit "reasonable probability" - people are often using way too high prior estimates without noticing.

Note that you can still have the Fermi paradox in the MWI if observations tell you life and intelligence should be plentiful: what needs to be explained is the absence of something we expect.

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  • $\begingroup$ On your second and third paragraph I think you misunderstand my proposal. The fundamental shift in logic changes from saying that: intelligent life is an event of x probability in a universe of y size, where x and y are unknown variables, to: intelligent life is an event of non zero x probability in a universe of arbitrary size, in which all possible sequences of events that have non zero probability are, at some point, "expressed" in the wave function (or in more concrete human terms: occur in a branch). $\endgroup$ – Hart Traveller Nov 27 '20 at 22:48
  • $\begingroup$ The problem is that you are trying to redefine what the Fermi paradox means from the common meaning. In your take it becomes trivial since anything with non-zero probability happens in some branches. You not only "resolve" the paradox, but also prove the existence of (physically possible) gods and unicorns. $\endgroup$ – Anders Sandberg Nov 27 '20 at 23:00
  • $\begingroup$ Indeed! I would say that gods and unicorns aren't even strange. A unicorn is just a horse with a pointy horn on its head. Also consider that my response to you passes through a computational infrastructure that would be magic, or godlike, to most people from history. The reconciliation of the fermi paradox with many worlds is a shift from a question of the unknown probability of life, to the assurance of life with a non zero probability. The practical implications of this suggest that we may be unlikely to ever find life in our branch, but indeed life may abound across the multiverse. $\endgroup$ – Hart Traveller Nov 28 '20 at 12:43
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An ingenious argument, but since the MWI suggests that "all possible outcomes occur in some universe", the MWI can be used to support any proposition.

There are some good reasons to think that intelligent life is extremely rare and we are the only example, in at least our galaxy.

  1. The lack of rubbish (crashed spaceships, discarded alien crisp packets, etc).
  2. We will probably spread out through the galaxy over the next 10 million years, stifling the development of other intelligent lifeforms. If another civilisation had beaten us, they would have done the same and we would not be here.
  3. ("Rare Earth hypothesis") As our knowledge of other stellar planetary systems increases, it is becoming clear that the solar system is anything but typical.

So, in short, there is a simpler and less exotic explanation that does not require or support MWI

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