Anybody Out There?

By Guy Kahane

These days it seems as if every couple of weeks or so we get reports about newly discovered planets that are ever more similar to Earth. The most recent discovery, planet Proxima b, is the closest planet found so far; Scientific American called it ‘the Earth next door’. Last October, an amateur group of astronomers noticed that the star KIC8462852 was flickering in an odd way, its brightness changing by up to 22 per cent, a much larger change than could be explained by any familiar cause. Some science fiction fans speculated that this might be a ‘Dyson Sphere’—signs of a super-advanced civilization desperately trying to harness energy from their sun. No convincing explanation of this effect has been found so far, and another star, called EPIC 204278916, was recently spotted exhibiting the same mysterious flicker. Then it was reported that Russian radio astronomers recorded a two-second burst of mysteriously strong radio waves coming from a sun-like star in the Hercules constellation.

We know we shouldn’t get too excited. Even if there are numerous Earth-like planets out there, they may all be lifeless. And scientists will probably eventually find perfectly natural explanations for these strange flickers and signals (the Russian report already seems to be a false alarm, caused by terrestrial interference). But still: it’s hard not to anticipate the day—perhaps in the coming few years, perhaps later in our lifetime—when strong, perhaps undeniable evidence of intelligent life elsewhere in the universe will emerge. It sure feels as if that will be an incredibly important discovery. Arthur C. Clarke once said that “there are two possibilities: either we are alone in the universe, or we are not. Both are equally terrifying.” But it’s not that easy to explain why.

Of course, if there is intelligent life out there, these extra-terrestrials may one day visit us, and they might not be incredibly friendly—a possibility that is terrifying in obvious ways. But even if we managed to discover signs of intelligent life on Proxima b, it is far from obvious that we would ever be able to communicate with the Proximans, and it could take many decades, possibly longer, to figure this out. As for mutual visits, for all we know it could be centuries before they become seriously feasible. But it seems that discovering intelligent life out there would be an immense discovery even independently of these practicalities (or impracticalities). I think it would change the way we think about ourselves. But spelling out how and why isn’t so straightforward.

You’d expect that philosophy would be able to help us here, but I think that most philosophers would be embarrassed to write (or even think) about aliens. You certainly won’t find much discussion of extra-terrestrial life in recent moral philosophy. This isn’t surprising. Moral philosophy is largely focused on questions about how we should treat each other and, and sometimes, more broadly, about what kind of lives we should live. But until the aliens knock on our door, there’s obviously no need for the sub-field of Alien Ethics. And whether or not we’re alone in the universe won’t directly change how we ought to live. It’s rather a question about, to use the clichéd phrase, ‘our place in the universe’.

I want to suggest one way in which it would matter immensely whether or not we’re alone in the universe—one way of explaining why Arthur C. Clarke was right. Suppose that in a hundred years from now, we destroy ourselves using nuclear weapons, or in some other way. That would be an awful thing. It would involve an unthinkable amount of suffering and death. And on top of that unimaginable evil, there would also be the loss of all the things humanity could have potentially achieved, of billions and billions of people who could have lived in the future but, because of our foolishness, never will.

But how important would our extinction be? Well, whether we stay around is obviously pretty important to us. But would it matter much beyond that? I think that this almost entirely depends on whether we are alone in the universe. Whether something is good or bad, wonderful or evil, largely depends on the nature of that thing. Suffering just is bad, helping others good, etc. But how important something is depends on what else is around. It depends on the value something has, as well as the difference to overall value that something makes, compared to other things. It’s far more important, in this sense, whether Hilary Clinton has pneumonia, or whether Donald Trump is telling the truth, than whether we have pneumonia, or are telling the truth (journalists are, rightly, a bit less interested in the latter than in the former). Or to give a very different example, Shakespeare’s work is so seminal because there is so little that compares to it, and because it has had such a huge influence. If Elizabethan drama was blessed with several other authors as great (or greater) than Shakespeare, then the loss of an early copy of Hamlet won’t matter as much—even though Hamlet, considered in itself, wouldn’t be any less wonderful.

In the same way, if we’re alone in the universe, or even one of a handful of intelligent species, then we would matter on the cosmic scale in a way we obviously wouldn’t if the universe is teeming with intelligent life. It would still be sad if we extinguish ourselves but, on the large scale of things, it just wouldn’t be that much of a loss. Intelligent life would go on, other civilizations would go to do great (or horrible) things… Our disappearance won’t deserve any special notice. It would be no more than a sad footnote.

This is why it would be terrifying both to discover that we are alone in the universe and that we aren’t. If we aren’t, and there is intelligent life all around, then we are pretty insignificant—important to no one but ourselves. But if we are alone then we are immensely important. If we destroy ourselves, then we are destroying not just ourselves, but also the only intelligent life in the universe, something incredibly special and rare… If all life on Earth gets extinguished, this might be the end of all value in the universe. As a species, we don’t seem to be bothered much by our (current) cosmic loneliness, but if it is confirmed, then everything we do (or fail to so) acquires an added layer of importance. This isn’t something to be terribly proud about—it’s not as if we would deserve credit for the cosmic coincidence of our singular existence. But it would be a great responsibility—actually, a pretty terrifying burden.

Now there is a lot more to be said. Does it really make sense to speak of things being important ‘on the cosmic scale’, as opposed to merely important to us? And can things really have value beyond the value we humans confer on them? I try to answer these questions, and a few others, in this rather long paper. But let me end by quoting some lines from the poem ‘The Ball’ by the Polish poet Wislawa Szymborska, who makes the main point far better than I am able to, and with far fewer words:

“As long as nothing can be known for sure
(no signals have been picked up yet),
as long as Earth is still unlike
the nearer and more distant planets,

let’s act like very special guests of honor
at the district-firemen’s ball
dance to the beat of the local oompah band,
and pretend that it’s the ball
to end all balls.”

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12 Responses to Anybody Out There?

  • Paul Treanor says:

    There seems to be an error of logic here, especially in this…

    This is why it would be terrifying both to discover that we are alone in the universe and that we aren’t.

    There is no way that we (humans) can ‘discover’ that we are alone in the universe. There is no way we can rule out intelligent life elsewhere, other than by thoroughly examining the entire universe, which is in practice beyond all possibility. The existence of intelligent life is not formally unfalsifiable, but we simply cannot answer the question. I am not an expert, but no doubt this asymmetry has been noted before. If the alien spaceships actually land here, we can be absolutely certain that the aliens do exist, but we can never be certain that they don’t exist. Their non-arrival says nothing in this respect.

    Nevertheless, it is possible that the history of science tells us something about the future, which may be relevant to the issues raised by Guy Kahane. We know that single observations do not necessarily settle major scientific questions, one way or the other. We know that uncertainty over major issues has sometimes persisted for centuries. We know that often theoretical questions were only settled, when technology made certain specific experiments possible.

    We also know that there is no historical record of an undisputed arrival of aliens, or undisputed alien communication. There is no other trace of aliens on this planet. We can conclude that such events are statistically unlikely.

    Now in the absence of those indisputable events, the existence of alien life must be inferred from observations, in practice astronomical observations. That includes the patterns which are mentioned here – unusual bursts of activity or unexplained regularities, detected by radio-astronomy. However, for all these events, alternative explanations have been advanced, and the history of science indicates that that process will continue, unless and until a definitive experiment is devised. Again this experiment is necessarily asymmetric, since we cannot prove the non-existence of alien life.

    No such experiment exists, and to my knowledge no-one has indicated how it might be constructed. So either we have an undisputed event, with actual alien spaceships, or an undisputedly alien communication, or we have disputed and speculative inferences from one or more observations. With that background, I think I can make a fairly safe prediction: 100 years from now the question will still be unresolved. There will be no proof that the aliens don’t exist, and no convincing evidence that they do exist. Moral philosophers cannot therefore wait for the ‘alien issue’ to be resolved, and ought to think about alternative approaches. (The possible existence of pervasive intelligent life, and the possible colonisation of space, do have some implications for political philosophy, but that’s a different issue).

  • Andrews says:

    Paul, you are missing the point. The point is not about the type of evidence that would yield knowledge about the existence or non-existence of aliens, or about when we will get this type of evidence. The point is rather: Assuming we *could* have knowledge about the existence or non-existence of aliens, what moral implications would this knowledge have?

    • Paul Treanor says:

      That’s not how the post presents it. It implies that the question will be resolved at sometime in the foreseeable future, at which time we will be able to adopt an appropriate sense of our place in the universe. If that was not what Guy Kahane intended, then perhaps he can say so himself.

  • Paul Treanor says:

    Let me put it this way. Guy Kahane says there are two possible states of knowledge on this issue…

    1. We know we are alone in the universe.
    2. We know we are not alone in the universe.

    In fact there are three options…

    1. We know we are alone in the universe.
    2. We know we are not alone in the universe.
    3. We don’t know either way.

    At present we are in state 3, we just don’t know. It is impossible to transition to state 1, because that would require exploration of the entire universe. The arrival of a fleet of alien spacecraft would move us into state 2, but that probably won’t happen today, or tomorrow, or in our lifetime. So essentially there are no ‘moral implications’ of the knowledge about our place in the universe, because we simply don’t have that knowledge. This post is apparently a shortened version of an earlier paper, and while that paper may be mainly about other issues, I still think that the logic is flawed by not recognising that human unicity is impossible to establish.

  • Andrews says:

    Sorry Paul, but from my reading of the text, nowhere does the author implies that your (1) and (2) are exhaustive. In fact, all the author does is to suggest, following Arthur C. Clarke, that the two following possibilities would be equally impressive: that we are alone, and that we aren’t. What the author suggests is that either possibility, regardless of their being epistemically accessible, would bear moral significance us. (More about this below.) The argument does not imply anything about our knowledge or beliefs in the hypothetical scenario the author considers. Thus the logical flaw you mention does not occur.

    However there is another question, not discussed by the author, that is closer to your critique; it is the question question as phrased above but this time dropping the qualification in bold, i.e. ‘What moral significance would the possibilities of being alone/not alone bear to us if this possibility was realized and in our epistemic reach if we existed in these scenarios‘? This question is closer to your critique, but still dodges it, insofar as it is an open question whether we could get decisive knowledge on whether we are/aren’t alone. It is an open question because the argument leading to the conclusion that we are/aren’t alone need not have the form of an ontological argument; all that knowledge would demand would be evidence that there are aliens or lack of evidence even after carrying out a “complete” (where astrophysics or some relevant science would define “complete”) research for evidence.

  • Anders Sandberg says:

    There are cosmological horizons that limit what we can reach and learn: even at lightspeed, we cannot reach galaxies currently beyond 5 gigaparsec because of the accelerating expansion, and even as time goes to infinity the radius of the observable universe remains finite. If aliens exist outside the eventually observable universe we (and them) can never know about each other.

    It is not clear to me we should view aliens beyond the horizon as existing in the same way as aliens within the reachability range: we could in principle causally interact with the later, but the former will never have any causal effect on us or vice versa. Can something you can never be affected by still affect your importance? Especially since their properties are arbitrary (within the possibilities set by nature).

    A solution might be to say that the importance should be measured from a hypothetical outside perspective, like God or the sysop of the universal simulation looking into it. But if one does not buy that as a valid, possible perspective (especially since a deist God or sysop is just as causally inactive as beyond the horizon aliens) then it looks like the measurement of importance has to occur from an inside perspective, and we might want to distinguish between in-principle reachable or detectable aliens and the ones that will never be connected to us.

    • Paul Treanor says:

      The astrophysical limits make no difference to the argument. Humans can not establish that there are no “in-principle reachable or detectable aliens “, because this so-called reachable universe is itself beyond all human survey. Far too big, much too far, and would take so long that humans were long extinct, by the time the exhaustive survey was complete. So in the end it comes down to the idea that we might/em> be the only intelligent beings in the universe, and in that sense cosmically significant. I don’t see why Guy Kahane can’t simply start from there, his argument does not seem to require any consideration of the probability of intelligent aliens. And as noted already, there are consequences for political philosophy if intelligent life is pervasive. That seems more interesting than the ‘cosmic significance’ issue.

      • Anders Sandberg says:

        The reachable universe looks like it is reachable and completely searchable; see my paper “Eternity in six hours: Intergalactic spreading of intelligent life and sharpening the Fermi paradox” for the physics. Even if you doubt that, one can always make smaller horizons and search them completely.

        How would the argument make sense if one discounts aliens, and then considers we might be the only intelligent beings? Isn’t that just saying “humans are the only humans, and hence cosmically significant”?

  • Andrews says:

    One would think that after 8 replies to a very simple idea people with more than higher-education would get to understand it and try to engage it directly. Let us then attempt a ninth pass then:
    Does the moral status of intelligent life on Earth, and does the moral significance of the lives of intelligent beings on Earth as a whole, vary depending on whether intelligent life on Earth exhausts intelligent life in the univers?

    • Paul Treanor says:

      The two questions are pointless unless it can indeed be established that we are the only intelligent life in the universe. Guy Kahane must take some blame here, because he posted a badly truncated version of a longer original. Apparently this is the original: Our Cosmic Insignificance NOUS 48:4 (2014) 745–772. This is his conclusion…

      If we are alone in the universe, the only thing of value, then this gives our continuing existence, and our efforts to avert disaster, a cosmic urgency, on top of whatever self-interested, anthropocentric reasons we have to stay around. That is to say, we might be far more important than we take ourselves to be.

      That seems at best superfluous, because of the overwhelming self-interest. But suppose we all accept this cosmic responsibility to preserve ourselves, if it turns out that we are the only intelligent life in the universe. The United Nations could, for instance, pass a resolution ordering all governments to pursue policies to preserve humanity, starting with nuclear disarmament. But before the UN did that, it would ask astronomers and exobiologists for official confirmation, that humans are in fact the ‘the only intelligent life in the universe’. And they can’t supply that confirmation, not now, probably not ever.

      So for all practical purposes the question of our cosmic significance does not matter. It would certainly matter, if aliens do arrive, and tell us convincingly that there are millions of intelligent life forms. They might sneeringly tell us that they don’t care if humans destroy themselves, because humans are an uninteresting life form with an uninteresting civilisation. That would certainly have an impact on us. But Guy Kahane’s question has no such impact, it’s all “what if” and “might be the case”.

      It’s worth repeating, that there there other issues about possible alien life and human colonisation of space, that have relevance for political philosophy. They are not the subject of this post however, so discussion is off-topic.

  • Patsy says:

    It’s good to get a fresh way of looinkg at it.

  • Kevin says:

    “[I]f we’re alone in the universe, or even one of a handful of intelligent species, then we would matter on the cosmic scale in a way we obviously wouldn’t if the universe is teeming with intelligent life.”

    “If we aren’t [alone], and there is intelligent life all around, then we are pretty insignificant—important to no one but ourselves. But if we are alone then we are immensely important.”

    It seems arbitrary and absurd to think that if we are alone (or almost alone) in the universe that we would be “immensely important” and “matter on the cosmic scale.” Rather, I suspect that other conclusions are better drawn, for example, that our concept of what is supposed to distinguish us from everything else that exists (i.e., our intelligence) is false. If we are alone, that means on a cosmic scale that we are not a thing at all.


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