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Asteroid Day 2024
What Would Alien Life & Intelligences Mean?
What could life be as we don’t know it? Three transitions in astrobiology. Non-life to life. Life to intelligent life. Intelligent life to technological civilization. For alien life, would Darwinian evolution hold? Fermi’s Paradox is profound: with at least 10^22 planets in the known universe, we find no evidence of alien life, anywhere, much less alien intelligence. Is there a great filter?
Contributors
- Robert Lawrence Kuhn
- I was 16-years old when terror struck. Terror at my existential isolation in an incomprehensibly vast cosmos. The trigger of my terror? Simple words of the French philosopher – Blaise Pascal – “The eternal silence of these infinite spaces terrifies me”. The eternal silence… Are we alone in the cosmos? These infinite spaces… Are there extraterrestrial lifeforms, alien intelligences… Anywhere? For hundreds of years, E.T. elicited fantastical ideas, spawning science fiction. Now, astrobiology has become a real science – we discovered hundreds of exoplanets, then thousands – alien worlds orbiting alien stars. Now, The James Webb Space Telescope reveals more exoplanets. Analyzing their atmospheres – Seeking signatures of potential life. But what is it all about? What would alien life & intelligences mean? I’m Robert Lawrence Kuhn and Closer To Truth is my journey to find out. Astrobiology is a science. And for the science, I look to our best telescopes. But to discern meaning, to give sense to the search for alien life and intelligences – I look to philosophy, I wonder about three kinds of transitions in astrobiology: From non-life to life. From life to intelligent life. From intelligent life to technological civilization. Transitions? Too weak. These are radical transformations! How to envision them? My perspective is philosophy of biology. I begin with a philosopher who focuses on historical science, anomalies in scientific discovery, astrobiology, and the nature of life – Carol Cleland. What contribution can a philosopher of biology make to the search for extraterrestrial life?
- Carol Cleland
- If you’re looking for extraterrestrial life, how are you going to recognize it? And a lot of biologists think the way to do this is to come up with a definition of life. But the problem with a definition of life – if it’s really a good definition and most scientists recognize this – necessary and sufficient conditions for life – which would box in the concept of life. So, anything that didn’t meet those conditions is not alive, and anything that meets those conditions must be alive. Yet, if we go elsewhere, to Mars, or especially a place like Titan, where if there is life, and there are lots of organic molecules, you’re not going to find life just like our kind of life on Earth. It wouldn’t survive. And so, the question is how would you recognize it? Well, our concept of life is basically built on a single example. So, how do we generalize from that single example? We don’t know how different life could be. Well, this is why my proposal is to allow ourselves to get beyond life as we know it here on Earth, is to look for potentially biological anomalies. And a potentially biological anomaly is basically a physical system that has certain characteristics that are highly suggestive of life from what we know on Earth, and characteristics that are completely unanticipated. It’s also the case that if you’re actually looking for potentially biological anomalies, you aren’t going to be fixating on a definition of life such as metabolism first.
- Robert Lawrence Kuhn
- In principle, could you have life without metabolism?
- Carol Cleland
- Depends on what you mean by metabolism. That’s the problem. So, is a tornado a living thing? It extracts energy from the environment to maintain itself, so does a hurricane. So, you have to be really careful about the difference between being able to do that biologically and not biologically, and we don’t know actually what that difference is. But there are nonliving systems that certainly do that. This is why looking for potentially biological anomalies is important. You would be able to include both metabolic characteristics and Darwinian reproduction characteristics, gene-based characteristics in such a search. And you would also include other characteristics, characteristics that might be common in environments such as the Atacama Desert. So, you could exploit how life adapts itself to various kinds of environments in your search strategy. So, instead of having just one particular, you know, defining characteristic that you’re looking for, you would have a suite of characteristics carefully designed for the environment. And now, the hope would be that if you got enough of those characteristics that were suggested, but it also had other characteristics that weren’t suggested, it would now be a candidate for further biological investigation for life. That’s the way to search for life as we don’t know it…
- Robert Lawrence Kuhn
- Carol cautions that the first step in searching for extraterrestrial life. Should be to question our biased definition of life. Defining life by our planet-earth’s one data point is too limiting. To explore “those infinite spaces”… we cannot be so anthropocentric. Is there another view, the opposite idea? That the deep principles of life as we know it are more universal? I go to England, to the Oxford University Museum of Natural History, to meet the distinguished evolutionary biologist – Richard Dawkins.
- Elizabeth Lloyd
- When I went to Princeton, to graduate school, I was interested in philosophy of biology. I had written a paper my first year there, and Bas van Fraassen told me it was publishable, so I thought, well, this is great. It was about the theory structure of evolutionary biology. But, nevertheless, I was told by the chair of the Princeton department, you can’t write your dissertation in philosophy of biology — it’s not a field.
- Richard Dawkins
- I’ll stick my neck out as far as saying that if there is life elsewhere, it will be Darwinian life. I think there’s no other way in which you can get to the sort of complexity of organization, and the illusion of design that life has. I’ve analyzed all the alternatives that have ever been suggested to producing life, and mostly Lamarckian and things like that, and then none of them work. So, even if on some other planet, acquired characteristics were inherited, even if the facts allowed that, it’s not a big enough theory to give rise to things like eyes, complicated things that really work through and through. You can’t make an eye like that. You can’t say the more you use an eye, the clearer you can see, or something of that sort. I don’t want to sound as though I think that life elsewhere will be just like it is here. It almost certainly wouldn’t be. But the one thing I would say is that it will be Darwinian. There’ll have to be some kind of genetics, and I bet it’s digital genetics like it is here. I would guess that it’s probably going to be carbon-based. People have occasionally suggested silicon, but I don’t think that has the necessary versatility of chemistry. And I suspect protein-based too, I think proteins are remarkable molecules that have the property of catalyzing as enzymes, catalyzing chemical reactions by great orders of magnitude, speed-ups of chemical reactions. So, I would bet that it’s going to be protein-based. I would not bet, bet on DNA. And certainly not the same genetic code, even if it was DNA.
- Robert Lawrence Kuhn
- One could say that there are three possible transitions for extraterrestrial life. There’s no life to life. There’s life to intelligence, and then intelligence to technology. Because we have many intelligent beings that are fossils here, they were intelligent in many ways, but didn’t develop technology. How do you see each one of those transitions?
- Richard Dawkins
- That’s a very important distinction, because if we ever did detect life on other planets, my guess is it will not be bodily life, because its distances are too great. And so it is going to be by radio, or by electromagnetic radiation of some sort. SETI, the Search for Extraterrestrial Intelligence, and intelligence is the operative word there, because if they’re not intelligent, they’ve got to be technological, actually, otherwise, they can’t send radio messages, and we can’t pick, pick them up. So, although the universe may be teeming with something like unicellular life, we are unlikely ever to know about it.
- Robert Lawrence Kuhn
- The barrier between non-life and life was a barrier, but not, not a significant one, but the one between life and intelligence is an enormous barrier.
- Richard Dawkins
- I think it is enormous. But on the other hand, the same statistical argument that says there’s got to, there’s got to be life, I think, applies to that as well. It may be that only some tiny fraction of 1% of life is intelligent life, but that’s still going to be a large number, given that we’ve got whatever it is, 10 to the 22 possible stars. So, intelligent life is going to be a lot rarer than life. But that probably still means it’s pretty common.
- Robert Lawrence Kuhn
- If Richard is right, the Darwinian Principles that govern the development of life on earth – would govern the development of Life everywhere! One can challenges Richard’s “Universal Darwinism” as anthropocentric –
But I can also challenge the challenger by asking: “How else, given naturalism, to develop lifeform complexity? Perhaps the third astrobiology transformation can help – from intelligent life to technological civilization. Here lies that terror of “The eternal silence”… It’s the deceptively simple “Fermi Paradox” – if the universe is teeming with intelligent life, where are they? I ask a philosopher of biology specializing in evolution and bioethics, with implications for astrobiology, Rachell Powell. - Rachell Powell
- The galaxy should be teeming with life. We should be seeing astro-engineering, we should be finding artifacts. And we don’t see any evidence of this for the entire history of the observable universe. And so, therein lies the paradox. But the paradox is only a paradox from the standpoint of the kinds of inferences that physicists are used to making. We’re in a garden variety solar system, and a garden variety star, and a garden variety galaxy.
- Robert Lawrence Kuhn
- Yeah, we’re Copernican, so we can’t be that special.
- Rachell Powell
- Right. So, the idea behind Copernicanism, which seems very reasonable, is there’s both sort of a statistical element, and a cognitive element. The statistical element is, well, we should expect that we’re going to be sort of smack in the middle of the distribution. The cognitive sort of corrective of Copernicanism is to be very wary of theories that would have human beings being privileged observers in some respect. And all of that has been vindicated by cosmology, astronomy, et cetera. And so, now the question is, well, what is the explanation here? What we have, really, is only one history of life. We’re dealing with an N = 1. And that’s a very different scenario than physicists are dealing with. And so now the sort of big question is, you know, what can we infer from the patterns and processes that have governed the history of life on Earth about the prospects of nature and frequency of different sorts of life elsewhere in the universe? So the reason why we can’t just simply project, you know, earthly evolutionary outcomes onto the cosmos the way we can with other kinds of physical processes is simply because we’re confronted with what sometimes is known as observer selection effects. So, if we’re talking about the evolution of complex intelligence, anyone asking the questions that you and I are asking today is going to have to hail from a history of life that went through all the steps necessary to get to that point where they could ask those questions. But all that allows us to see is that our outcome is consistent with the laws of physics. It doesn’t say anything about the constraints on that outcome, whether or not it’s likely to happen again, or not. And a lot of evolutionists have been highly skeptical, I think, of extraterrestrial intelligence, largely because they kind of have a big picture view of the history of life on Earth that looks like life taking this sort of meandering pathway of twists and turns, replete with historical continuances that would never happen again.
- Robert Lawrence Kuhn
- Right, Gould’s famous thing, if you ran the movie again.
- Rachell Powell
- Right. Exactly.
- Robert Lawrence Kuhn
- It would have a totally different result, every single time. Of course.
- Rachell Powell
- And the reason why this is important is because there’s nothing in the laws of biology as we know them that gives you the kind of specific evolution of forms that we’re talking about. And that’s where convergent evolution comes in to be significant. Because the argument is, well, actually, we’re not dealing with N = 1. We have a history of life that shows a great deal of replications, which are essentially considered, you know, tantamount to natural experimental replications in this life. We can’t rewind the tape, but we can watch all these different replications play out from different initial conditions in the history of life on Earth. And it’s, when we look at that, it suggests, some people think, that there are these sorts of laws of form, specific ones, that are somehow underlying the contingent choppy seas that we see above, but it’s pulling form into specific direction. So, my work has been concerned with, is well, how do we parse this big data set of convergence in a way that allows us to say that some types of convergence do look like they’re evidence for a kind of deep replicability that would have implications for things like the rewinding the tape of animal life, but also, like life on other worlds? So, I think that, sort of at the end of the day, the evidence for replicability of body plans, like vertebrate body plans, mollusk body plans, arthropod body plans, is very weak. There’s really no evidence for convergence in those forms. But when it comes to properties of mind, it’s quite a bit of a different story. The reason why convergence is so important is because it gets you around observer selection effects. That’s the way you can get distinctively sort of biological data and theory to support some kind of a more cosmic biology of body and mind.
- Robert Lawrence Kuhn
- What is your then solution to the Fermi Paradox?
- Rachell Powell
- So, you have the replicability of minds. You even have the replicability of persons in dinosaurs, in birds, and mammals. But there’s a huge gap between the evolution of persons and the evolution of cumulative technology.
- Robert Lawrence Kuhn
- So, that’s your filter.
- Rachell Powell
- I think that the filter is in the evolution of cumulative cultural capacities. What one could reasonably conclude, given the Fermi Paradox data, the great silence, is that they’re extremely rare, and they never get very far…
- Robert Lawrence Kuhn
- Assuming that there is alien life, Rachell has alien intelligent life, which many evolutionists have as vanishingly rare, as less rare, more common, due to convergence in the replication of minds – the idea that mentality, in some form, is a natural consequence of complex development. It’s a big idea, with warning signs – teleological purpose? Slippery slopes? And the “Great Filter,” she says – why there’s no evidence of alien intelligences – is that the evolution of the cultural capacity to accumulate is extremely rare. These radical transformations, to me, are the crux of astrobiology – in particular, intelligent life. Alien transformations to life and intelligence are my targets. I pursue them with an evolutionary biologist who became a philosopher of biology – Massimo Pigliucci.
- Massimo Pigliucci
- One of the fundamental pieces of theory underlying the whole SETI project, is the famous Drake equation, which is bad news. Because it was proposed in the 1950s. In terms of history of science, when a field is essentially theoretically stuck in 70 years earlier, it’s not good news. It means that not a lot of progress has actually been made. And of course, why has no progress been made on the question? Because we still have a data point of N = 1. We haven’t discovered anything.
- Robert Lawrence Kuhn
- Arguably, there has been progress in one of the terms that dealt with the number of habitable planets. So, that one term, we’ve made some progress.
- Massimo Pigliucci
- That is correct. Things get really complicated when we get to fundamental aspects of the Drake equation that have to do with, let’s say, how frequent is life on planets that have at least the physical characteristics that appear to be conducive to life? Once life has emerged, what are the chances that actually it gets so complicated to generate intelligence, the kind of intelligence that produces technology, we have absolutely no idea. If it does, how long does that kind of civilization last? You know, does it last long enough that we actually have a chance to perceive signals that are generated by such intelligence? Again, we have no idea. We just don’t – we only have – not even a single data point, in that case.
- Robert Lawrence Kuhn
- Yeah, we don’t even know our own…
- Massimo Pigliucci
- Exactly, because we’re still alive. Our civilization is still around. So, the bottom line is there is an incredible amount of uncertainty there. I think that because we do know that life on Earth originated fairly quickly after the physical, geophysical situation sort of settled down in a range of parameters that was conducive to life. And so, that would suggest that although we still don’t actually have a number that we can plug into the Drake equation, that number might be significantly high. But after that, any guess, you know, is just as good as any other guess. That’s part of the problem. The other problem is that if you think about it the entire SETI project, it’s really based on a narcissistic assumption. That is that alien life, intelligent life out there, it’s pretty much like us. That these beings are psychologically like us. They’re curious. They want to communicate. They’re interested in technology. These are all things that are essentially human. But then there is, as you know, another issue which I did not take seriously enough when I was younger, and it now worries me increasingly, and that is the Fermi Paradox. So, in my mind, the bottom line is that the entire SETI project is based on a sample size of zero in terms of actual findings. Nor do we have a reasonable assessment of the probability of success. Of course, all of this could change tomorrow. But that has not happened for several decades, and there is no reason to think that it might actually happen in the immediate, or even the long-distance future. We just don’t know. It’s one of those situations where the theory is so undetermined by the data, as philosophers like to put it, that it’s not even funny.
- Robert Lawrence Kuhn
- I take seriously Massimo’s move away from a universe teeming with life, his increasing worry about the Fermi Paradox. Given the vast number of planets in the habitable zone of host stars – and for an alien civilization to achieve galactic breakout, only one such alien civilization – Only one! – would be needed, The Fermi Paradox remains a paradox. Given that Pascal faced his terror – the eternal silence of infinite spaces – almost 400 years ago… I seek an expert in the subsequent history of philosophical obsession with alien life. I meet a philosopher of cognitive science and of religion, who also studies archeology, art, and science fiction, Helen De Cruz.
- Helen De Cruz
- Philosophers are very coy about extraterrestrials. Basically, you have to go all the way back to Copernicus where you have the heliocentrism, and heliocentrism just literally says the sun is at the center of the world. But then it was clear that the world, the solar system, is just one of many, as they called it, worlds. So, you had Giordano Bruno who I think is seen as the first person to draw out the full implications of this, and he would look out and say there’s many solar systems. If we go a little bit later, we look at philosophers such as Bernard de Fontanelle, French philosopher. So, he has a popularizing book about conversations on the plurality of worlds. They thought the solar system is filled with space aliens, and you know, those distant stars, they might have planets, right? So, this was a very common idea. So, Kant, in 1755, wrote a book about the nebular hypothesis. So, he hypothesized that the nebulae you see in the distance, that they are really galaxies. And that was actually his innovation, 1755, and it took until the early 20th century with telescopes, because Kant was just looking at it and thinking yeah, it could just be, you know, like space dust, or it could be galaxies. I’m saying these are galaxies because it’s such a beautiful hypothesis. But then you go several centuries ahead. The nebulae really are galaxies. That at the same time, it feels sort of alone, right? That philosophers are a bit hesitant to talk about it, but I think they shouldn’t because it’s such a, such an interesting topic, and there’s a rich philosophical tradition to draw on.
- Robert Lawrence Kuhn
- Didn’t you have a quote by Blaise Pascal in that paper, which was actually, it very moved me, because that was the first philosophical idea that affected me as a teenager. Something like, the eternal silence of the infinite spaces scares me.
- Helen De Cruz
- Yeah, it frightens me. I think this is a feeling, and it comes almost out of nowhere, at the great and vast unknown, and maybe indeed the thought, imagine if we’re all alone. I hope not. That is a horrific thought.
- Robert Lawrence Kuhn
- Either way, to me, is both frightening and exhilarating, whether we’re alone or not alone. I’s one of the, what I would call it, one of the ultimate questions.
- Helen De Cruz
- Yes, I feel like there’s a sense of hope. I think that’s what comes with the idea that there’s many, many other alien species. Like, we are citizens of the cosmos. So, the question about how we even think about how we relate to others on this planet is going to have ramifications of how we think, how we’re going to relate to space aliens. Like, if you’re thinking about, like, colonialism, imperialism. Then you’re going to think, yeah, you know, this is maybe not so great if the world is filled with, with alien life. Or you could be like a cosmopolitan optimist. But then if you’re thinking like, this is it, I think it’s just like, I don’t know. I find that a frightening thought that we’re all alone because if the lights go out here then it’s done. Like, I find that an unbearable thought.
- Robert Lawrence Kuhn
- About astrobiology, here’s what we know For Sure: The three Radical Transformations happened right here on our Earth. Non-life to life Life to intelligent life. Intelligent life to technological civilization. The number of cases of these transformations is precisely One. But from one data point, how to predict? Here’s how the arguments play out: To seek “life as we don’t know it,” define life in the most general, non-human-centric terms. Although life in the cosmos is likely totally different, yet, Darwinian principles are likely to hold – the optimal and perhaps only way to build complex biology. The huge gap, the key transformation, is between the evolution of “persons” and the evolution of cumulative technology. The Fermi Paradox is as profound as it is popular – “The universe should be teeming with life – so where are they?” There are dozens of imagined solutions – perhaps the great filter is culture. Perhaps intelligent life? Truth to tell, we just don’t know. Humans have speculated about aliens for centuries. Yes, “The eternal silence of these infinite spaces terrifies me”. Yes, for decades, “The eternal silence of these infinite spaces.” Has driven me to get – and to do… Closer To Truth.