Didn’t mean that as a barb of any kind; only an observation. Glad to see wider participation!
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@jongarvey can you way in? I’d be curious your guess before I put mine forward.
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Hmm - reminds me of the 100 Year Old Tree, in that what actually caused this biological similarity is different from how people might come to believe it was caused. (And, to be prosaic, how it happened is irrelevant because it didn’t - it is fictional and we can invent any cause we like).
If we start from God - he is Creator of all things in Alpha Centauri and Earth, so the thing is only more remarkable in degree than finding a flower that looks like a human face or cosmic fine tuning. Whatever secondary means he used in creation, or not, he intended to produce mankind, so logically he intended equally to produce alienkind. Why not end them up at the same place? The theological question would then be why God did it that way. Is rationality, or the image of Christ we perhaps share, so closely linked to physical form? Well, what do you know - it seems God has some inter-stellar mankind in view. But whatever motive they give to God, all of them will be certain that “there is a grandeur in this way of doing things that would never have been met by maiking them different.”
Those excluded from the theological conversation by their profession are, perhaps, divided into two camps: the Aboriginalists and the Convergentists. The former insist that the two races must share a common root, however unlikely. Neither race owns up to seeding the other, and both seem to have their own long biological history. But evolution is contingent, so one way or the other there was a forgotten migration, or directed panspermia at some stage, and by some agent, yet to be determined (but our boys are working on it…). But convergence to that degree is a silly idea: evolution wouldn’t work the same way twice even in identical environments.
The Convergentists, however, accept the evidence of non-shared ancestry and point to convergent evolution here on earth, which is no more easily explained. Such a degree of convergence, they say, certainly suggests that evolution is a lawlike process at some level, perhaps through laws of form or… well Simon Conway-Morris hints at self-organising propensities we haven’t yet uncovered, so there’s a line of research to try. Maybe the races have comparable phylogenies, or maybe the aliens came via a completely different evolutionary route - it makes little difference: it’s just a different mechanism of convergence, which will teach us a lot about our own world as well as theirs. After all, wolves and thylacines have separate ancestry but even have convergent gene complexes. The aliens are like us, so the convergence certainly happened, and we just need some theories to account for it. But don’t talk about pseudo-science like common origins…
The beautiful thing is that, given the likelihood that no explanation can be found in the sketchy geology or theoretical meanderings of two worlds, the debate can potentially run on for centuries, the relative popularity of the theories being affected by how materialistic either or both cultures are, or even on how interplanetary relatioships are going - amazing how the Aboriginalists fall out of favour during the bitter Galactic War of 2134, but experience a resurgence when peace breaks out.
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Other sci-fi plots, of course, include morphing aliens, deliberately cloned lookalikes to take us over, and some _original _ ideas we shouldn’t mention here before writing the bestseller novel.
On the theological side, and amongst conspiracy theorists, the plotlines revolve around Nephilim.
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Before I answer I should point out that @vjtorley’s skepticism is totally warranted.
I know of no observed case where two large animals have independently evolved to be more reproductive compatible with time. The chances of this happening are mind bogglingly low. This is not convergent evolution in any way we have ever observed before. The only way interbreeding between species has ever made sense is if they shared a common history.
So convergent evolution is really totally implausible. Sure, bats and birds both have wings. But killer whales are not going to evolve the ability to bear true genetic merged offspring with sharks. Perhaps we see this with microbes at times, but given what we know of biology, this is totally implausible with human like beings.
@Patrick, take a stab at the riddle?
Well, the premise starts with fiction. The possibilities bifurcate depending on whether the humans and visitors are related by some form of linear, common descent or ‘artificially created’. We’d really need more background info about the visitors to differentiate between these options.
To be honest, I’m not sure that travelling interstellar distances in humanoid form is a likely scenario. It’s useful for a plot device to transport people but interstellar travel makes sending AI’s and computer hardware-based life a more tractable proposition. Interstellar travel is a very complicated and expensive undertaking. Adding space and materials for long-term support of human-like life is cost multiplier.
There have been scifi plots where the transport hardware constructs biological life upon arrival at a suitable system where raw materials are available. If the ‘construct humanoids on arrival’ scenario is the case, then with sampling (or perhaps by receiving data over the airwaves), perhaps an AI could design and generate human-compatible beings.
Alternatively, it’s conceivable that humans were sampled millennia ago by some other space-faring, AI-based species, these humans reconstructed on a different planet, and that their descendants are being reconstructed by an AI-based transport that has now traveled to the Sol system. That would be a quasi-linear descent with encoding/decoding model.
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Before I give my answer, should we invite participation from others? Much like we did for the Hundred Year Tree? If we can get participation, seems like that could be fun?
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Hi Joshua,
@swamidass
This is pure fiction, a CS Lewis styled imagination. Not Scientology.
OK, let me guess. Perelandra?
Looking back at the captured planet scenario I proposed, I’d be the first to acknowledge that it is, after all, astronomically unlikely (sorry about that pun) - especially my suggestion about egg-swapping between the two planets. And as you point out, hyper-deterministic evolution wouldn’t explain the ability of the aliens to interbreed with us. Creationism would be a more rational inference.
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Let me have a second shot at this, from a different angle.
May I assume that we, at least, are attacking this as if there is a God, whatever his role may or may not be?
Both Vincent and Joshua deny the possibility of the evolutionary process to operate separately on two separate worlds to produce interbreeding species. And that’s obvious, because interbreeding is the usual definition of one species, and how could one species be produced in two entirely independent galaxies?
I’d suggest that even if, per impossibile, the two worlds were identical twin worlds in the initial conditions, the natural processes we know would surely have at least enough contingency to prevent convergence on an interbreeding species so long into the tree of life - the process is simply not that precise: our “accidental” chromosome fusion alone would render fertile (if any) offspring impossible.
A little thought shows that, were God to wish evolution to produce that situation in the two worlds using natural processes and initial conditions alone, “with no necessity for supernatural intervention” (Collins, Language of God) the process is still not that precise, and the means would be insufficient. Unless any of you guys know different?
But to produce two identical (interbreeding) species is actually no more difficult than producing a single one of them to match a teleological template - that it, it is no more possible for God to “plan” or “intend” mankind, as the species we are, using entirely “the laws of nature” than it would be for him to produce our identical aliens as well as us. And if God did not intend to produce us as the species we actually are, but only something vaguely like us, then it is misleading to say “God intended mankind.”
So Vincent is right - the SF scenario favours special creation - or at least highly directed evolution. But if so, then the same must be equally true for the contention that “God used evolution to produce mankind.” The natural process in both cases is insufficiently precise for the teleological purpose - there must have been divine action of some kind, whether miraculous, concurrent or occasionalist is irrelevant, during the process.
Vincent also agrees with me (in another discussion) on the impossibility of Molinism covering the problem: conceivably God might choose to create the one universe in which “chance and necessity” produce mankind - just as he might choose to create the one universe where it produces two identical species in different galaxies. But all that would tell you is that he used a rather cack-handed way of directing every mutation in the history of evolution to his desired end - which, as I said in my post on Molinism, is a designed universe by any other name.
For God to visualise a range of possibilities and to realize only the one that matches his will is exactly what I have done with this post - I have created it as it is, by design.
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So, anyone else interested should try and give this a shot. Invite a theologian if ytou know one to contribute an answer this week.
In a week or two I’ll give what I’m thinking.
I see no problem with God engaging in “highly directed evolution”. I think that’s pretty much the whole point.
Hi! Our host invited me to take a stab at this one, so here we go.
Before I had a chance to read all the replies, I had a few ideas.
- Homo sapiens is some sort of attractor in biochemical phase space. This is essentially the convergent evolution hypothesis that has been previously explored and rejected, with an extra wave of the hands towards a justification.
- A species which has transcended biology travels through space as silicon-mediated minds, then synthesizes biological bodies using native species as templates in order to interact in a way that is comfortable for the locals. I like the incarnational aspect of this one. It turns out to be basically a variation on ideas already proposed by jongarvey and Argon.
- The Bekenstein bound says that the maximal amount of information needed to describe a physical system is proportional to the radius of a sphere bounding that system. For finite systems, that puts a finite bound on the information needed to describe them. Some have postulated this implies that if you go far enough out into space, you’ll find an identical Earth because there are only finitely many possible contents for Earth-sized spheres. So maybe these folks have traveled far enough to be from our doppelgänger planet.
That last one does not appear to have been already proposed, at least in that form, so that’s my guess for now.
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Thanks for joining us @AndyWalsh. Looking forward to discussing your book with everyone July 1, on science, fiction, and theology.
I’m not sure about that. The Bekenstein bound is:
S \leq \frac{2 \pi k R E}{\hbar c}
Where S is the entropy (i.e. information) and E is the mass-energy, and the rest are constants. But mass energy increases proportional to the volume of the sphere, so the bound is:
S \leq \frac{8 \pi^2 k R^4}{3\hbar c}
So, as the radius increases, the maximum entropy dramatically increases, faster than the volume of the sphere. Given that false predicate, the consequent is certainly suspect:
For that to be the case, we’d have to be seriously going far beyond our galaxy, and perhaps beyond the boundaries of the visible universe. Even then, it would still be stunning for them to be reproductively compatible, not just visually the same.
So, I’m not buying this one.
Yes, this one could be plausible.
What if these aliens can show this is not the case? What if they have a history and planet of their own? Perhaps they are just as surprised as are we that they are reproductively compatible. What then?
Yeah, not buying it. Could explain why they look like us, but not why we are reproductively compatible.
Oy vey, so many ‘if-then’ conditionals!
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It’s all in fun =).
I’d say it’s just further evidence that the universe just isn’t wired for “casual sex.” All in fun, of course! : )
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Is this a riddle with a specific answer, or are we trying to persuade you with a solution?
The bound is still finite, even if it grows quickly. As I understand it, that’s the key element. (For the record, the idea that the Bekenstein bound implies identical states if you travel far enough away is not mine; I believe I first encountered it as part of Tegmark’s multiverse hierarchy.)
Oh, for sure we’re talking about extraordinary distances. You did say they were from very very far away. As for reproductive compatibility, I think that’s implied by the fact that the exact same information describes their world as ours. And yes, it would be stunning, although possibly explained if there was a deliberate effort to search out matching worlds.
Switching to the attractor scenario:
Well, if it is truly Homo sapiens that is the attractor, then that implies compatibility. And while such an attractor is exceedingly small relative to the overall phase space, mathematically that’s not impossible. One can have an attractor of arbitrarily small measure, at least for some dynamical systems.
Switching to the synthesized body scenario:
I probably was too terse, but I was imagining that the aliens have a history and planet of their own, a history that includes developing the ability to move their minds between biological bodies and silicon storage. But I gather you mean that these particular reproductively compatible bodies were from the other planet, hence the surprise.
The surprise rules out a lot of other scenarios wherein the aliens themselves either arranged the compatibility or faked some of the tests. But I suppose it doesn’t rule out deliberate intervention by other parties. I’m now imagining some sort of galaxy-scale zoo in which we are unwitting exhibits. Maybe the zookeepers used some sort of CRISPR-like technology or the ever-popular nanobots to surreptitiously change the aliens to have genomes compatible with ours.
Or maybe we should conclude that we ourselves and our new alien friends are all characters in a sci-fi universe with biologically disinterested writers.
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