Extraterrestrial Life: The Need for an Answer

by Paul Gilster on March 22, 2011

An article in Time Magazine’s latest issue caught my eye as I thumbed through it while waiting in line at the grocery store. The magazine is running a feature called ‘10 Ideas That Will Change the World,’ and they tend toward being optimistic takes on huge problems. Thus the deficit gets an essay about how we’re going to fix it, while Afghanistan gets a thumbs-up for progress in the right direction. The article finds gold in everything from direct mailings (OK because they help charities raise money) to modern airports, which are creating a new kind of community.

And in the midst of this is a puzzling piece by Jeffrey Kluger called ‘Relax: You Don’t Need to Worry About Meeting E.T.’, where the upshot is: ‘Don’t worry about contact with extraterrestrial civilizations. It will never happen.’ Here’s a quote:

Humans and aliens haven’t connected yet, but with 1022 stars out there (that’s 1 with 22 zeros), it’s just a matter of time — right? Wrong. If exobiologists have learned anything, it’s that you and your kids and their kids’ kids will probably never hear the slightest peep from an alien. If E.T. the movie star is your idea of what extraterrestrial life might be like, you will be disappointed. If your thoughts run more to War of the Worlds, you can breathe easy.

Breathe easy? Let’s assume for a moment that Kluger is right, that contact with an extraterrestrial civilization is simply not going to happen at any time soon or in the future. If we knew that to be the case, would it be a cause for relief? For optimism? Maybe I travel with the wrong crowd, but most of us would be disappointed at the thought that we might never know whether intelligent civilizations exist around other star systems. Even those of us who think a confirmed SETI signal is unlikely any time soon — and I am one of these, believing that intelligent life is extraordinarily rare — would still hope to be proven wrong, and thrilled if we were.

Failure Is Not an Option

Kluger mentions both ‘E.T.’ and ‘War of the Worlds,’ so he’s not just reacting to disaster-oriented invasion films like ‘Battle: Los Angeles.’ The magazine seems to be implying that just the knowledge that we are either alone or unable to communicate with other civilizations is the solution to what Time bills as one of our worst problems. That phrase is used in the lead-in to these ten essays: ‘Our best shots for tackling our worst problems…’, of which knowledge of an alien culture is billed as number three on the list. And I’m wondering, since when is the idea of failing in our attempts to gain scientific knowledge considered the solution to a problem?

The essay goes through the difficulty in finding ETI, including our reliance on a sample of one to construct theories about life’s development on a planet, our uncertainty about how likely life is to develop even on worlds similar to our own, and the difficulty in finding an alien culture through SETI. That last point gets a quote from Don Brownlee (University of Washington), who notes the distances involved in going from star to star in the galaxy and says, “If the nearest hundred or thousand stars don’t have life, we probably won’t ever, ever, ever know about it anywhere else.”

That’s an interesting point if you strip it down to its basic assumptions. Picking up signals from a civilization something like our own would be a hugely difficult proposition even if they were being broadcast from a place as nearby as Centauri B. Pushing the distance out to a thousand light years makes things even more problematic. But we don’t know how long civilizations can exist, and the possibility of one living long enough to be thousands of years — if not millions — more sophisticated than our own can’t be ruled out. The factors that make a chance reception of a signal from a civilization like ours so tricky would be negligible to such an advanced species.

That possibility is one reason why we continue to look. And the fact that we have a sample of just one living planet to base our conclusions about life on is why we continue to look for life elsewhere, to broaden the sample and learn more about life’s mechanisms. So I don’t find any of this convincing in terms of making our detecting an alien civilization less likely to occur.

SETI, Distance and the Odds

But the point about stellar distances is still an interesting one. For one thing, we have a new paper by Joseph Catanzarite and Michael Shao (JPL) analyzing the Kepler science results that attempts to extract an estimate on how common Earth-like planets are. Let me quote from its summary:

Kepler’s science team has determined sizes, surface temperatures, orbit sizes and periods for over a thousand new planet candidates. Here, we show that 1.4% to 2.7% of stars like the Sun are expected to have Earth analog planets, based on the Kepler data release of Feb 2011. The estimate will improve when it is based on the full 3.5 to 6 year Kepler data set. Accurate knowledge of nEarth is necessary to plan future missions that will image and take spectra of Earthlike planets. Our result that Earths are relatively scarce means that a substantial effort will be needed to identify suitable target stars prior to these future missions.

We’re dealing with results that will be improved as the Kepler mission continues, but the figures so far cited indicate that planets like ours aren’t terribly common. Yes, it’s true that even with these low percentages, the option is still open for millions of Earth-like planets throughout the galaxy, given the sheer number of stars involved. But that other big imponderable — the question of how long civilizations last — still faces us. If they don’t tend to survive very long after they develop the ability to destroy themselves through technology, then Brownlee’s point has more resonance. And certainly these numbers say the nearest Earth-like planet may be a substantial distance away, a fact that will make studying it even more challenging than we first thought.

So yes, looking for ETI is difficult. But I can hardly share Kluger’s certainty in Time. He ends the essay, having looked at the possibility of alien extremophiles on Earth, by saying this:

Of course, even such aliens would hardly be the kind we either crave or fear — those who could regale us with tales of what things look like on the other side of the cosmos on the one hand, or conquer us with their superior intellects on the other. Too bad — or maybe very good — you’re never going to see them.

‘Never’ is a curious word to use in the midst of a great scientific investigation, one in which we hope to start assigning some reasonable values to the Drake Equation and find out just where we stand in terms of our place in the galaxy. We know so little, and Kepler and CoRoT are only the beginning of our space-based exploration of exoplanets increasingly like our own. We all have our views on this, and some of us are going to be proven wrong, but our investigations into extraterrestrial life are among the most energizing scientific projects in the history of our species. How could anyone possibly regard a failure to learn the answer as a good thing?

The paper cited above is Catanzarite and Shao, “The Occurrence Rate of Earth Analog Planets Orbiting Sunlike Stars” (preprint).

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Eniac March 24, 2011 at 10:02

As to the tired arguments about why “complex life”, “intelligence” and so on must be rare consequences of life, Rob Henry has addressed this quite well.

Let me remind about a few, again:

Mitochondria: simple instance of endosymbiosis, a common phenomenon.

Multicellular life: Happened independently at least a dozen times.

Intelligence: A consequence of the evolution of behavior. To outsmart is to outcompete. Will happen only once because the first instance will inhibit any others, due to complete and global dominance of the intelligent species.

Moon: What is it with the moon? Why do people bring up the moon all the time?

Observationally, we have before us: One try, one success. We have one confirmed occurrence of life, and in that case intelligence DID develop. That puts the odds at “very likely”, although with some uncertainty because of the small sample. Should we find more instances, we can and will refine this estimate.

Anthony Mugan March 24, 2011 at 10:14

Ronald – thanks. Just to clarify the life vs intelligence vs technological civilisation aspect. The concept I was attempting to put forward (not very clearly, evidently!) was that if life itself is plausibly common in the universe then the fact that we can state that the probability of an advanced civilisation developing is not zero (based on the fact that we exist) deals with the question of the existance or non-existance of other technological civilisations, given the literally astronomical number of potential habitats and timescales available for the probabilities to play out. Of course that still leaves us with no way of assessing the actual numbers involved or average seperation, without making lots of other assumptions. That said it does seem to boil down to a technological question – is interstellar travel possible, in a reasonably practical sense, for an arbitrarily advanced civilisation? Assuming they survive that long they would become more or less immune to even stellar system scale catastrophes and it then becomes a matter of time for the civilisation to spread. That is basically the same point as Ken Olum (2004) was making (ref in earlier post).

Bynaus March 24, 2011 at 11:21

@Eniac: I agree on Mitochondria and Multicellular life, but not here:

“Intelligence: A consequence of the evolution of behavior. To outsmart is to outcompete.”

Not necessarily. There are an infinite number of ways to outcompete, and evolution takes a random path through them. Claiming intelligence is a natural outcome of evolution is like claiming, say, an elephant’s trunk is, as well. Yes, elephants developed a very flexible trunk because they outcompeted other elephants with less flexible trunks – but that doesn’t mean that on other planets, where evolution took a completely different direction, elephant trunks will develop. Elephant trunks are not selected for “in general”, but only in very special circumstances. That equally applies for intelligence.
In addition, every benefit comes at a cost (larger head, higher energy cost, etc.). It is by no means sure that if conditions had been different, the benefit of higher intelligence in humans would have merited the cost.
And finally, intelligence alone is not enough to build a civilization: you need means to manipulate your environment, and means to communicate your thoughts efficiently with others. To find all that together in one species is certainly not very likely.

I disagree here, as well:

“Observationally, we have before us: One try, one success. We have one confirmed occurrence of life, and in that case intelligence DID develop. That puts the odds at “very likely””

This is exactly what I meant by the “anthropic bias” I mentioned before: If there were no success, we would not be here, there would be no observation of the whole process. Even if there was only one success in the entire observable universe, the picture would not change, as we would see: one try, one success. Puting the odds at “very likely” because of the single try in the universe that by definition HAD to succeed, makes no sense at all.

“Moon: What is it with the moon? Why do people bring up the moon all the time?”

The moon stabilizes the Earth’s rotation axis. The obliquity of the Earth would vary chaotically if there was no moon, therefore there would not be any stable climate zones. If one considers stable climate zone as a prerequisite of a civilization building species, then the absence of a moon inhibits civilizations.

Anthony Mugan March 24, 2011 at 11:31

Eniac – I concurr with your analysis of the anthropic principle to a point – although I balk somewhat at a totally relativist stance. I am a bit puzzled by the conclusion that we are more likely to be in a universe in which life is possible but rare. This is difficult to quantify (at least for me!), but qualitatively, in a universe which is well tuned for life there should be many observers, and few in those where it is less likely. If I understand it correctly the interplay in tolerance ranges accross the various fundamental constants seems to allow relatively limited scope for adjustment whilst allowing for life. There ‘possible range’ of universes suitable for life would appear to be quite narrow. Instinctively this feels like we would be more probably in one that strongly favours life, as the number of observers would tend to be much higher there than in the slightly different universes that could just manage to support life occassionally…? I could be completely missing something of course and I can’t even begin to quantify this judgement.
Just as a further addition, really to my previous post – the question of the probability of intelligent life emerging is of course uncertain. Complexity theory, or convergent evolution as it has become in biology, tends to argue for a higher probability. Professor Conway Morris of Cambridge is a leading proponent of this view. This is controversia, at least to the extent that Conway Morris argues the ‘inevitability’ of it, but seems to be gaining ground (I seem to remember reading a balanced but broadly supportive comment on it from Richard Dawkins of Oxford, for example, in an online debate with (I think!) Michael Shermer). Certainly not a definite result at this stage as we can’t quanitfy the dynamics of mutliple fitness landscapes to confirm the probability is indeed high, but…

Rob Henry March 24, 2011 at 18:43

Bynaus, the idea that there are many alternative answers to those problem of living that can be fixed by increasing intelligence is a wonderfully counterintuitive and sound idea. I am however unsure that the idea that on some worlds every line of challenged life forms will take such alternate routes on every possible occasion is equally good. To that effect I would like to add some unusual evidence to the contrary.

The old explanation as to why most bilateral animals appear so symmetric externally is that sexual selection selects for it in all groups because it is a marker of good genes, however this explanation is rendered unworkable in light of the fact that most adult asymmetry is due to environmental damage (if you find a fit and healthy mate that has overcome horrific injury, they must have truly fantastic genes). I believe that Enqulst and Arak have the true answer. They have shown that in any sufficiently complex neural network, a left leaning identified aspect that will trigger recognition better than a right leaning one (or visa versa), there is also a trend for the central expression of this aspect to trigger recognition nearly as much as the preferred orientation.

In that case, all is we need to do is to prove that some early information processing has a bias in some groups – and never in latter groups, and we would have a prima facie case that neural networks increase in complexity beyond their minimum needs in all groups. Earth’s example give us strong evidence. Babcock and Robinson have shown that 70% of all bite damaged trilobites sustain that damage on their right sides!!!

spaceman March 24, 2011 at 19:59

Based on these initial estimates for the fraction of solar-type stars with Earth analogs, it seems that next generation space-based telescopes will have their work cut out for them. Seems like it will have to be big expensive interferometers in order to look at enough stars to have a decent chance of finding a habitable world.

On the other hand, has any one read the Marcy et al paper that recently was released on the preprint archive? It is titled “Planet Occurrence within 0.25 AU of Solar-type Stars from Kepler.” Solar type stars is the key word in the title. As Catanzarite et al mention, there could be more habitable planets around smaller cooler stars. This is bolstered by Figure 8 in the Marcy et al paper which clearly shows that the overall planet abundance is ~0.30 for M dwarfs and planet abudance increases for small stars (at least for planets of the sub-gas giant variety)!

Rob Henry March 24, 2011 at 20:50

Actually Bynaus, your approach for the importance of the moon has similar validity problems. The moon definitely promotes climate stability on Earth. The problems lie when you try to use it in a Rare Earth type argument. This is best illustrated by Ward and Brownlee themselves, when, in an attempt to create their scenario, they posit that extreme climate and environmental variation promotes the emergence of complex life when generated by Snowball Earth and Meteorite impacts, but retards it when it just so happens to be generated by axial tilt instability due to the absence of a sizable moon.

Bynaus March 25, 2011 at 5:50

@Bob Henry: I am not saying that intelligence will not appear on any other world. Just as there are probably some elephant trunks somewhere out there, there will also be intelligence. We should just not expect it to be a common outcome of evolution. It is a fallacy to think that evolution has a certain direction, a certain goal, and that goal is intelligence. It’s random, it can’t have a certain goal.
We marvel at our own intelligence, and in retrospect, one could easily think that evolution was directed towards the evolution of our intelligence. But if the elephant were to do this, and was very proud of his trunk, he could equally claim that all evolution was directed towards the formation of his trunk, and he would be equally right, and wrong about it.

I am not sure I understand your argument regarding symetry and the implication you propose for the complexity of neuronal networks. I would think that the reasons for symetry would be stability and a simpler body plan that can be grown more or less symetrically along at least one axis (usually the spine).
It may well be that intelligence was first developed by sexual selection, until some practical aspects took over. But I guess that would make the evolution of intelligence (a priori) even more unlikely.

kzb March 25, 2011 at 12:13

I don’t think there is even a need to bring in multiverses to the anthropic universe theory. We are here to observe the universe that came into being from a superposition of possible big bangs. It’s a quantum theory of the big bang. Non-observed big bangs are virtual.

Chris T March 25, 2011 at 14:26

Out of around 70 classified phyla, only one has produced a species capable of creating a civilization. Out of 12 classes within that phylum only one has produced a species capable of civilization. Of 29 orders within that class only one has produced a species capable of civilization. Of 16 families within that order only one has produced a species capable of civilization. Of 4 (living) genera within that family only one has produced a species capable of civilization.

The number of species that have ever existed on Earth is in the billions. Yet we only know of one that has ever created a technical civilization. It is notable that one suborder of megafauna dominated for 160 million years without ever producing a civilization capable species or any signs of one developing in that direction.

I would hardly call human intelligence inevitable.

Rob Henry March 25, 2011 at 15:10

Sorry Bynaus, if my explanation was too short. My middle paragraph was entirely a diversion to set up the third and only important one above. Even as a setup, external symmetry within animal body plan is only of any importance to this argument where internal asymmetry is compared to external asymmetry (early animals tended to have a high degree of internal symmetry, so this would complicate direct comparisons of sexual selection now v then), and it is this difference that is acknowledged as due to sexual selection. The process of object identification via a neural network has been shown to have a general tendency to favour symmetric objects. Although any one sub-programmes used in this selection process would have a high likelihood in overcoming this process, if it is attenuated through a complex series of sub-programmes, this would be increasingly less likely to give asymmetric results. Now the only important bit… Predator prey relationships are mediated via visual fields. In the early Cambrian there is known to be a strong asymmetry in this process, and we thus know that the software that ran it must be very simple.

My criticism of your moon factor was also obtuse – since I only spoke to just the class of argument. Actually the specific factor of the lack of stable climate during the development of higher civilisation was intriguing. It implied that the Holocene stability was necessary rather than coincidence, yet that has played out over 10,000 years whereas the lack of a moon should surely only play out over time spans of 100,000+ years. I put it to you that your speculation is also interesting enough to also fill out some gaps.

Rob Henry March 25, 2011 at 16:02

Chris T, the type of argument that you put forward seems okay, but I always feel that it is framed in the wrong way. There always has to be one technological civilisation that is first, and then the process might be expected to suppress subsequent species that would otherwise move into that niche. Thus the real question is: is 530 million years after the Cambrian explosion suspiciously long for us to take this emergence as inevitable?

Thankfully the brain size in the most complex creatures from many other phyla has also shown a strong increase with time. This brain growth shows such a clear pattern that it may be possible to test your speculation. Perhaps your idea can then be tested by estimating the time until the encephalisation quotient from several other groups is similar to the human case, or alternatively explain why such a robust trend will mysteriously halt.

Bounty March 25, 2011 at 16:52

“The great Greek philosopher Epicurus already postulated that in a field with many grains it is highly unlikely that only one grain will germinate.”

Maybe, but if Epicurus had seen my “garden” last year, he would have seen a low number of germinations, followed by natural disasters (birds, insects, me.) None of those plants went on to communicate their DNA as far as I can tell. Things may have gone better in other galaxies…. I mean gardens.

Ronald March 25, 2011 at 18:42

Rob Henry: “the Holocene stability (…) has played out over 10,000 years whereas the lack of a moon should surely only play out over time spans of 100,000+ years.”

This is highly relevant, if so.

I have always doubted the necessity of a (large) moon as a stabilizer of the earth rotation and hence its climate.
First of all, how strong is the stabilizing effect of our moon in comparison with the inherent stability of the earth rotation itself, like a gyroscope, surely this must be known.
Secondly, and this is where your point comes in, how strong would the climatic instability be without our moon, in comparison with other climatic factors (in terms of both amplitude and frequency).

If this is indeed only noticeable over >100,000 years, it may not even be an important (inhibiting) factor in the development of life.

Chris T March 25, 2011 at 19:25

Rob – Brain size and complexity has indeed increased with time in several species in different phyla (the octopus in phylum Mollusca is a notable example). But substantial encephalisation is a necessary, but not sufficient condition for a technical civilization.

Any such species needs also have the ability to manipulate its surroundings extremely well. This leaves out avians and most aquatic species.

The octopus might have the required dexterity, but civilization requires the ability to manipulate energy. Water is a terrible medium to do this in due to its high chemical reactivity and its high electrical conductance. The octopus itself is not remotely adapted to land and shows no signs of moving in that direction. So any species would have to be terrestrial. (They would also need an atmosphere that’s reactive, but not too reactive).

Intelligence is not solely determined by the overall size of the brain. Organization and the size of structures within the brain matter as well. H. Neanderthalensis actually had encephaolization comparable to modern humans, but did not even come close to our achievements during their 100,000 year history.

Any such species also has to survive its early years. Any random cataclysm could make them just another extinct species (massive volcanic eruption, asteroid impact, etc.). Most branches in the Homo genus were dead ends before we arrived on the seen. H. Erectus isn’t even believed to have overlapped with any other species geographically in the genus and went extinct anyway (although it did last about one million years).

Earth’s evolutionary history isn’t exactly promising.

Rob Henry March 25, 2011 at 20:17

Chris by dismissing EQ as relevant, you are dismissing one of the few criterion that I know of that might yield objective results, in favour of arguments that just feel right. Are you sure that this is a good idea, or have you hit upon another way of testing your hypothesis.

Eniac March 26, 2011 at 0:45

Instinctively this feels like we would be more probably in one that strongly favours life, as the number of observers would tend to be much higher there than in the slightly different universes that could just manage to support life occassionally…? I could be completely missing something of course and I can’t even begin to quantify this judgement.

My take on this is that we know of ONE instance of intelligence. There could be more, but it is not necessary to explain our observation. Thus, according to Occam’s razor, we prefer the hypothesis that requires the least tuning, and that is the range of realities where life is possible, but barely. Surely no ultimate truth, but enough to convince myself, for now….

Eniac March 26, 2011 at 0:51

Claiming intelligence is a natural outcome of evolution is like claiming, say, an elephant’s trunk is, as well.

Not really. An elephant’s trunk, as you say, is a limited adaptation, good for certain niches. Intelligence, on the other hand, is a game changer, nearly instantly making one species the ruler of all. It is way up there (or even beyond) the advent of DNA, protein, photosynthesis, and multicellular life, none of which happened fast, but nevertheless were inevitable given enough time.

Eniac March 26, 2011 at 7:24

It is a fallacy to think that evolution has a certain direction, a certain goal, and that goal is intelligence. It’s random, it can’t have a certain goal.

This is correct. However, just as an ant walking around randomly will eventually come across the sugar in your pantry, evolution will eventually arrive at those game-changing advances I mentioned earlier, including intelligence. Once it happens, there is not turning back. So, random, yes, many false starts, yes, but these are not at all incompatible with inevitable.

Not really. An elephant’s trunk, as you say, is a limited adaptation, good for certain niches. Intelligence, on the other hand, is a game changer, nearly instantly making one species the ruler of all. It is way up there (or even beyond) the advent of DNA, protein, photosynthesis, and multicellular life, none of which happened fast, but nevertheless were inevitable given enough time.

Chris T March 26, 2011 at 12:22

Rob – I didn’t dismiss EQ. I simply stated it alone wasn’t enough and we know this to be true.

Dolphins have a relatively high EQ, but even if it was much higher than ours, it wouldn’t matter because they don’t have any way of manipulating the world around them.

You’ll also note I gave several examples of species that had a high EQ, but nevertheless did not accomplish what we have before going extinct (and existed for much longer). That’s hardly just giving arguments that ‘feel right’.

Necessary, but not sufficient.

Chris T March 26, 2011 at 12:39

Intelligence, on the other hand, is a game changer, nearly instantly making one species the ruler of all.

If this is true, then why did one suborder of megafauna dominate for 160 million years, but fail to produce a species that went this route?

There have been several other species in the Homo genus, yet all but ours tended to be restricted to one or two continents.

Rob Henry March 26, 2011 at 16:42

Chris T, the arguments behind the riders you list might work very well within a limited scope, and may very well explain why the process took half a billion years from the Cambrian, yet none look any good as absolute halts. Examples are…

The reign of the dinosaurs shows that there can be temporary setbacks such as after the end Permian extinction. The first dinosaurs might have contained some examples where their brain mass was ridiculously low, yet their trend for increasing brain mass was strong throughout the Mesozoic, and still continues. Today they are some of the most frequent tool users, and African Grey Parrots seem to be one of the few animals proven to understand abstract concepts.

Your example that brain structure probably also needs to increase in complexity to attain intelligence also work well within the concept of slowing the process. However, the fact that brain complexity also shows a general trend to increase with time in some animal groups attests to the ubiquity of the evolutionary drive to increase intelligence – and that it is more than strong enough to overcome that barrier.

Your cephalopod example is perhaps the most interesting of all, since it demonstrates that dexterity and intelligence are not as strange a combination as you earlier implied, nor that the aquatic environment is a barrier to this. At least this suggests a possible test of certain aspects of your hypothesis. Are there any signs of communal habitats, build by one (extinct) species of cephalopods over the last few million years (most counter-proponents such as myself would feel that this group is not quite ready, but feel that some test being better than none). Certainly, no one would have looked for them or recognised them if they found them without a dedicated search, so at least this test would start from a clean slate.

The difficulty of developing technology in the sea is a very interesting one, but it should just mean that technological civilisations that come from an aquatic environment are built by citizens that are more intelligent than those from land based technologies.

Your only examples that completely mystify me are of hominids unique development. Wouldn’t the evolution of any particular animal look like a fluke if examined in isolation?

Rob Henry March 26, 2011 at 19:04

Chris T, there may be another good analytic way to test your theory, and our failure to see it might rest on that unusual human trait: war. Because humans have a tendency to spontaneously divide into groups and start killing each other as if it were a game, and because race is helpful in such group selection, we have a tendency to improperly downplay race differences in IQ tests. The objective evidence is that Raven progressive matrices are very good at extracting g irrespective of cultural background across all human groups. It is therefore fairly likely that this would extent to a valid test of other species whose intelligence is dominated by a visual sensory input. Cetaceans have very high EQ’s yet are unable to use tools so they are also outside the problem that the first civilising intelligence will suppress subsequent emergences. Cetaceans are actually dominated by acoustic input, but finding a way to entice them into trying to solve Raven matrices type problems, might be a start in your quest to make your argument a testable, and thus scientific one.

Eniac March 26, 2011 at 23:36

Chris:

If this is true, then why did one suborder of megafauna dominate for 160 million years, but fail to produce a species that went this route?

I did not say that intelligence would develop at every opportunity, just that it will, eventually. Dinosaurs did not make it, but mammals did. The more opportunities, the more likely the result. If not today, then tomorrow. Rob’s observation of increasing EQ advances this argument beyond just the random walk, in that emergence of intelligence becomes increasingly likely as more and more species with bigger and bigger brains roam the Earth.

Also, in case you meant to imply this, dinosaurs did not “dominate” the Earth the same way we do. Not even close. They were many different species, each with their niche beyond they could not reach. We, on the other hand, spread all over the Earth as a single species. We are in complete control of all other macrofauna, and we eliminated a lot of other hominids that probably would have reached this stage eventually, hadn’t we been first.

Now, we are getting ready to spread into inhospitable outer space, an unprecedented step in the history of life. As with all the other important steps, though, unprecedented does not imply rare and unlikely, as too many people seem to think.

I except from this abiogenesis, which I do think is rare and unlikely because it did not have the benefit of evolution as a driving force. But that is from a different thread… :-)

kzb March 28, 2011 at 7:36

Eniac, the problem I have with intelligence being almost inevitable is that logically it means something else in the chain is very rare.

That is because the one nearly concrete fact we have is that technology-capable species are very rare in the Galaxy.

So if you posit that evolution of intelligence is a likely event, logically that means that biogenesis is extremely rare. Or possibly that development of eukaryotes is rare etc.

Chris T March 28, 2011 at 13:50

Rob – Overall complexity doesn’t matter as much as what is complex and how it is wired. The dog has an olfactory bulb 40 times the size of a human’s. They can differentiate smells far better, but it won’t help them achieve space flight any time soon.

We also know that how a brain is wired is a major component in cognition. This is certainly heavily mediated by genetics and therefore evolution. It may be that technical civilization requires a particular neural organization. Answering this will require a much better understanding of how the human brain works.

nor that the aquatic environment is a barrier to this.

It’s a barrier to technology however. Water is far too chemically reactive and conductive to electricity to allow much manipulation of energy (absolutely critical for technical development). It’s density would also make activities that require a lot of force very difficult (try shaping a rock under water).

The objective evidence is that Raven progressive matrices are very good at extracting g irrespective of cultural background across all human groups. It is therefore fairly likely that this would extent to a valid test of other species whose intelligence is dominated by a visual sensory input.

Actually, it’s probably not all that likely. Cognitive tests like the Raven are designed for an operational definition of intelligence in one particular species. Extending it beyond humans would be unlikely to provide much useful information. Once we have a physical definition of intelligence, we can attempt to compare species, but we’re unlikely to get very far before then.

Your only examples that completely mystify me are of hominids unique development. Wouldn’t the evolution of any particular animal look like a fluke if examined in isolation?

I was making the point that similar EQ in other species was not enough on its own to allow civilization. H. Neanderthalensis and H. Erectus both virtually had entire continents to themselves for a much longer period of time than humanity has existed and failed to progress very far. This suggests that there is something specific to human neural physiology that has allowed civilization.

Chris T March 28, 2011 at 14:03

We are in complete control of all other macrofauna, and we eliminated a lot of other hominids that probably would have reached this stage eventually, hadn’t we been first.

What’s in dispute is the ‘probably’. H. Erectus did not spatially overlap with any other hominid for close to one million years, but died out 200 kya.

Rob Henry March 28, 2011 at 15:37

Chris T, your entire argument rests on concatenating several scientific speculations, several of which have little or no evidence to back them. This approach can be only be seen as an appeal to authority unless it is backed by a raft of testable predictions, thus my desperations to entice you into revealing them.

Raven progressive matrices were not so much designed as tests of operational human intelligence as hit upon as such. They seem to work without aid of any learned human skill, or human specific trait such grammar. I agree that we look on the threshold of a better understanding of intelligence, and perhaps even a physical definition may eventually be possible, but until you propose some test in the here and now, your rare development of intelligence idea looks more religious than scientific.

Rob Henry March 28, 2011 at 16:08

Kzb, working backward from another incredibly complex problem such as the Fermi paradox, to make implications over the development of intelligence is fraught with dangers. To illustrate, let me do the same within the doomsday argument.

What is the chance that a typical sentient being within a technological civilisation gets to note that it exists on the home planet of its species? If galaxies are already full of civilisations this would be high, but if typically each emergence finds itself alone in a galaxy it should go on to populate at least a million other planets, and many of these new worlds are likely to have cumulative populations that exceeds that home world by the end (the big rip?). Therefore, from the location of our own existence, we can conclude that most galaxies are already full, and so the evolution of beings that can build advanced civilisations must be extremely common.

Let us try to find more direct ways of estimating these factors, or we will achieve nothing other than honing our rhetorical skills.

Eniac March 29, 2011 at 0:39

Chris,

It is a little like the lottery: It is very unlikely that I will win the lottery, ever, but it is quite inevitable that it will be won by someone within the next week. Of course, we cannot quantify this when it comes to things like evolutionary biology, because we do not know the odds. But then again, natural selection is a strong driving force that the lottery lacks, and the time available and number of players (species) are both vastly larger. So, my position is at least plausible, and surely the opposite is very difficult to prove.

There are a large number of revolutionary developments that are no less wondersome than the emergence of human civilization. In our lineage, where they could be explained by the anthropocentric/Bayesian argument, but also outside, where this argument does not hold. Insect organizations, for example, are much like our own in many respects, they even build large buildings. Most of the arguments you make could be applied to them. But they do exist, and it is not because our existence requires them.

Intelligence is special not because it is particularly difficult to develop, but because of the unique advantage that it provides when used for the control of nature. It is transcending in the same way that the development of photosynthesis was, or the colonization of the land, but even more so. It allows us to keep any of our fellow animals for food and as pets, or to drive them to extinction. It allows us to unleash nuclear energy and fly into space. It frees us from evolution itself, by invalidating natural selection and giving us full control over our genome.

That said, intelligence most likely developed originally not for the control of nature (in technology), but for the control of fellow humans (in commerce, politics and war). To outsmart is to outcompete, and it is, quite objectively, a much more powerful way to do so than an elephant’s trunk, a dog’s nose, or whatever else you may hold up. Ask any elephant or dog …

Eniac March 29, 2011 at 1:00

So if you posit that evolution of intelligence is a likely event, logically that means that biogenesis is extremely rare. Or possibly that development of eukaryotes is rare etc.

Exactly. I have said more than once in these pages that abiogenesis is the most likely suspect, on account of the lack of a lineage.

As regards Fermi, it is either that, or an unspecified inevitable event in our future that will stop us from colonizing the stars.

kzb March 29, 2011 at 13:35

Rob Henry -are you saying that most other galaxies are full? I’m afraid you need more than logic to convince me of this !

Eniac and I are at least sticking to falsifiable hypotheses. Say we discover that there IS life on one or several exoplanets, in several different systems. That is the abiogenesis hypothesis blown out the water. (This is something that could actually happen in the next few years.)

The explanation of the Fermi paradox must then be something else. You then move to pick the next thing off the list.

Rob Henry March 29, 2011 at 15:48

Kzb, I think your missing something subtle about your earlier comment. I fully agree with the way your now (comment of 29 March) examining the Fermi paradox – although, of cause, I think you meant to write that if we found several independent occurrences of life it would validate abiogenesis as likely – not life on other exoplanets. If that happened that would indeed spotlight our examination of other factors, yet your choice of word in the earlier post almost implied that we should use this spotlight to overwhelm more direct evidence relating to the remaining factors.

And yes I meant to imply that the doomsday argument spotlights a group of factors that include galaxies being full. This should induce us to look closer at them, but my whole and only point in that comment was that we should NEVER use that as equivalent to direct evidence of a populous galaxy.

Chris T March 29, 2011 at 19:44

Chris T, your entire argument rests on concatenating several scientific speculations, several of which have little or no evidence to back them. This approach can be only be seen as an appeal to authority unless it is backed by a raft of testable predictions, thus my desperations to entice you into revealing them.

Any argument on this subject suffers from a lack of data. The only real data we do have on life is from our own planet. All of my statements have come from a reading of our current understanding of life’s history and neurobiology. I have provided that data and why I make the inferences I do.

You have made hypothesized that there are high odds for the development of civilization capable life based on the fact that a number of evolutionary branches have shown an increase in EQ over time. One of those resulted in us.

I have answered with several lines of evidence that, to my mind, run counter to that hypothesis:

1. Several species within genus homo had similar EQ and lived for an extended period without ever developing much beyond crude stone tools and small bands of hunter/gatherers. One went extinct despite being isolated from contemporary hominids after one million years. Another lasted for several hundred thousand years in isolation, but disappeared not long after contact with modern humans.

2. Neurobiology has shown that intelligence is not simply a function of size, but organization. People with high IQ scores tend to have more efficient neural organization:

http://www.sciencedaily.com/releases/2011/03/110303111423.htm

2b. Many social functions, such as facial expression and language acquisition, are believed to be hardwired:

http://www.sciencedaily.com/releases/2008/12/081229080859.htm
http://www.psychologytoday.com/blog/brain-sense/201002/infant-brains-are-hardwired-language

Hypothesis: Human cognitive ability owes to the organization and increased density in specific structures within the brain. The morphology of the human brain was the result of a unique set of evolutionary pressures. A far better understanding of the human brain is required to accept or reject this hypothesis is required.

3. High technology requires the manipulation of chemical, electrical, and thermal energy. Water is an extremely good solvent and finding or producing sufficient quantities of various chemicals would be difficult to say the least, let alone reacting them. Sea water is a good electrical conductor relative to air and electronics require significant insulation if they’re used underwater.

Hypothesis: Any technical civilization must be terrestrial. A plausible sequence of increasingly sophisticated energy manipulation underwater leading to a radio capable civilization would undermine this hypothesis.

4. High technology requires a highly developed ability to manipulate the environment in addition to intelligence. Some avian species have developed several facets of human intelligence. However, they lack the dexterity to manipulate it beyond simple tool use. The only known order that has developed morphology suited to finely controlling their environment are primates.

Hypothesis: Highly dexterous morphology is even more unlikely than human intelligence in terrestrial species. Examples of morphology outside primates demonstrating a similar level of manipulative ability would undermine this hypothesis.

Raven progressive matrices were not so much designed as tests of operational human intelligence as hit upon as such. They seem to work without aid of any learned human skill, or human specific trait such grammar. I agree that we look on the threshold of a better understanding of intelligence, and perhaps even a physical definition may eventually be possible, but until you propose some test in the here and now, your rare development of intelligence idea looks more religious than scientific.

My evidence is that when Earth’s history is taken in aggregate, the development of a life form capable of high technology is so rare that we know of only one example. I can only assign probabilities using information I have and the information (Earth’s history and the Fermi Paradox) I have suggests a low probability. This is subject to change as more data becomes available.

Failure to find after looking is not evidence of absence, but absence is the leading hypothesis until evidence of existence is found.

Rob Henry March 29, 2011 at 23:03

Sorry Chris if I sounded judgmental, but the way your last comment outlined your argument was what I was looking for all along. I can now at least agree with your position, if still be unconvinced of you conclusion.

That also induces me to add that you look right about dexterity being low in relation to the primates, but wonder it your test should be confined just to that group. Elephants have large brains and a much finer control of their trunks than apes do of their hands. Perhaps that situation should also be investigated for potential?

Certainly there is much to think about.

Rob Henry March 29, 2011 at 23:29

Actually Chris your last sentence also brought up an interesting side issue. Who first quoted “absence of evidence is not evidence of absence” that you paraphrased above, and why is it so widely quoted in scientific circles.

Because it is often hard to attach any statistical significance for a lack of evidence, often the only thing that we can truthfully conclude following a failed search is that absence of evidence really is evidence of absence. But I know what you mean.

kzb March 30, 2011 at 7:59

Rob Henry, yes what I meant to say was that if independently-arising life is discovered elsewhere, that means the explanation of the Fermi paradox must be something other than the spontaneous generation of life being unlikely.

When you think about it, if we found just ONE example of independent life in our corner of the galaxy, that would be enough to reach this conclusion with reasonable confidence.

I’m finding this discussion instructive. When I started out I favoured an Asimovian galaxy, where primitive life is common but development of technological intelligence very rare.

I’m now beginning to think this position is illogical. That is because, statistically, it is abiogenesis that is the more unlikely step. Yes both are unlikely, but the chances of abiogenesis are uncounted trillions to one, whereas surely the evolution of technological intelligence, once life has started, is not as statistically unlikely as that ?

Eniac March 31, 2011 at 9:47

If what I speculated earlier is true, and intelligence evolved primarily for social interactions rather than manipulation of the world, the ability to use tools would not be a prerequisite for intelligence. Dolphins might eventually develop language and thought just as complex as ours, to communicate best hunting grounds and fish-catching techniques, and to outsmart sharks and other dolphin . No opposable thumbs required.

Once there is language and culture, can technology be far behind? Even without hands, there is a lot you can do with your mouth, and multiple dolphins working together should be able to assemble devices from components such as sea shells, kelp, and whatever else is available. In any case, while manipulation is certainly important contributing factor, I think it is sometimes way overrated as a necessary precondition to intelligence.

Similarly with energy. You can build quite some technology without fire, using animal power and mechanical contraptions only. As, in fact, we ourselves have done for most of our civilized existence. We have used fire mainly for warmth, which in the sea is not really necessary, and have learnt to use it as a source of power only in the 1800′s. Before that, animals were the primary source of power, and those are available in the ocean as well.

Adam April 5, 2011 at 0:09

Hi All

Chris T said

I was making the point that similar EQ in other species was not enough on its own to allow civilization. H. Neanderthalensis and H. Erectus both virtually had entire continents to themselves for a much longer period of time than humanity has existed and failed to progress very far. This suggests that there is something specific to human neural physiology that has allowed civilization.

Suzana Herculano-Houzel’s work on neurology hints that bulk neurones have a lot to do with humanity’s intelligence compared to other mammals, though not amongst the primates. We’re a linear extension of basic primateness in our brains…

Suzana Herculano-Houzel’s Comparative Neuroanatomy Lab

…which challenges some of the truisms of comparative intelligence.

Adam April 5, 2011 at 1:40

Hi again

Just some updates on paleoanthropology germane to this discussion…
(1) Neanderthals have passed on up to about ~4% of their genes to our current population. They are now known to not be a separate species. So calling them such is mistaken. Sub-species, regional variant, whatever term, but not species.
(2) Contrary to earlier findings, by the same people, East Asian “Homo erectus” didn’t persist past ~0.5 mya. For some years a skull had been dated to c. 50 kya(+/-23 kya) but this claim was found to be mistaken and the skull redated to 500 kya, by the same team who first made the younger claim.
(3) African “Homo erectus” transitions pretty clearly into early “H. sapiens/heidelbergensis” and then to “H. sapiens sapiens” (Hss) and “H. sapiens neanderthalensis” (Hsn), over the period 1 mya-0.3 mya.
(4) There’s evidence for regional gene lineages right back to “H. erectus”. The old argument between “Out of Africa” and “Multi-Regional” origins for our current human species has been effectively resolved in favour of both theories. Aspects of both have been confirmed, while the extreme versions have been rejected thanks to the genetic and morphological data.
In sum we have been one species for at least 1 million years, but with regional variations and sub-populations playing a large role in the observed transitions of populations through time.

ljk April 6, 2011 at 10:24

Metrodoros of Chios said that famous quote about the amount of grain growing in a field compared to alien life, not Epicurus. BTW, when the ancient Greeks talked about other worlds, they meant what we would currently call whole other universes, not just planets circling other suns. Aristarchus of Samos was one of the few back then who conceived of a universe similar to the modern version. BTW 2, Galileo said something similar, but being Italian he used a field of grapes instead of grain.

Ironically while we know more about the Cosmos in general than those old fellows ever did, we still have just as long a way to go when it comes to proof (or disproof) of extraterrestrial life. That’s why we need to be so careful when declaring whether we have lots of celestial neighbors or few. Even our knowledge of exoplanets is meager (do NOT mistake quantity for quality), so let’s not decide whether SETI is a waste of time or not just yet, okay? Maybe when we finally get a few probes to the nearest stars and can check out things in detail we can then start honestly declaring this and that. Though I realize we may have to travel farther than that to answer The Ultimate Question.

Let us get back to the original theme of this article for a change. The underlying theme of the Time magazine article is of fear – fear of the unknown and what it might be capable of, based primarily on humanity’s historical experiences with other members of its species. Note how even one of the early commenters in this thread said how his wife, a historian, was relieved to learn that aliens won’t be contacting us any time soon if ever, according to the Time author. While this fear is neither unprecedented nor unexpected, it is very sad in my book to see how many people still take what is one of the most profound and exciting questions in science and human history and actually want to turn the clock back on it out of primal fear. This is the Cosmos, folks, not the terrestrial savannah or the jungle. It is a different playing field by its very nature, whether or not our galactic neighbors are nice or nasty.

As I have said elsewhere on Centauri Dreams, the likelihood of an attack by an advanced alien race is slim for a variety of reasons (and no worries at all from an ETI just one century behind us), but if they want to destroy us there are several methods that will be quick, powerful, and virtual unable to defend against. So we need to stop worrying and start exploring. This anti-progress attitude will do us in far more probably than any marauding aliens. Besides, hiding under our cultural beds and not knowing what’s out there will not protect us from any cosmic threats, to be sure. Yes times are difficult at present but there have been far worse problems in the past and humanity not only recovered but advanced significantly often as a result of adversity.

ljk July 21, 2011 at 0:55

Life might be rare despite its early emergence on Earth: a Bayesian analysis of the probability of abiogenesis

David S. Spiegel (1), Edwin L. Turner (1, 2), ((1) Princeton, (2) IPMU, University of Tokyo)

(Submitted on 19 Jul 2011)

Life arose on Earth sometime in the first few hundred million years after the young planet had cooled to the point that it could support water-based organisms on its surface. The early emergence of life on Earth has been taken as evidence that the probability of abiogenesis is high, if starting from young-Earth-like conditions.

We revisit this argument quantitatively in a Bayesian statistical framework. By constructing a simple model of the probability of abiogenesis, we calculate a Bayesian estimate of its posterior probability, given the data that life emerged fairly early in Earth’s history and that, billions of years later, sentient creatures noted this fact and considered its implications. We find that, given only this very limited empirical information, the choice of Bayesian prior for the abiogenesis probability parameter has a dominant influence on the computed posterior probability.

Thus, although life began on this planet fairly soon after the Earth became habitable, this fact is consistent with an arbitrarily low intrinsic probability of abiogenesis for plausible uninformative priors, and therefore with life being arbitrarily rare in the Universe.

Comments:

10 pages, 5 figures, submitted to PNAS

Subjects:

Earth and Planetary Astrophysics (astro-ph.EP)

Cite as:

arXiv:1107.3835v1 [astro-ph.EP]

Submission history

From: David Spiegel [view email]

[v1] Tue, 19 Jul 2011 20:00:00 GMT (1291kb,D)

http://arxiv.org/abs/1107.3835

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