The Eerie Silence: Renewing Our Search for Alien Intelligence, Paul Davies

Recently in Silent Worlds, Empty Worlds I mentioned that I was listening to Paul Davies’ book The Eerie Silence: Renewing Our Search for Alien Intelligence, and this is the “eerie silence” to which I refer in the title of this post. Since that earlier post, I’ve listened through Davies’ a couple of times and also consulted the print version.

While listening to Davies’ book it occurred to me that a skeptical SETI argument could be formulated on the basis of the methodological naturalism that is the working presupposition of science — and presumably the presupposition of SETI also, if indeed SETI is a science.

The argument would run like this: the remarkable success of science in describing and explaining the world from the scientific revolution of the early modern period to today is predicated upon methodological naturalism. If this methodological naturalism was an invalid presupposition, then science so predicated would never have been the wildly successful enterprise that it has been. But science has been successful, and methodological naturalism has therefore proved itself.

Given the power of the intelligence to completely transform the environment in which it lives, as human beings have transformed the surface of the earth, an advanced extraterrestrial civilization that had managed to survive in the long term and to propagate itself at least within the confines of its solar system (as we have done to a limited extent) or perhaps also across interstellar distances, it would be the case that such an alien civilization would have transformed the environment throughout the region of space in which its influence held sway.

If any alien intelligence were to make a careful scientific study of our solar system, from the point of view of methodological naturalism certain anomalies would arise that could not be explained by purely naturalistic processes. The more detailed the study, the more anomalies would emerge. If the vast and cool and unsympathetic alien scientist got around to studying the surface of the earth, this scientist would eventually have to conclude that intelligence was at work, because natural processes could not plausibly account for cities, radio communications, and the other manifestations of technological civilization.

Similarly, when our scientists study other regions of the galaxy, methodological naturalism has proved to be a sure guide in understanding what we see. If large regions of space had been transformed under the influence of alien technology, anomalies would emerge in naturalistic explanations, and the more we looked, the more anomalies we would find. In fact, we do not find anomalies that can only be explained by recourse to explanations based upon intelligent intervention.

Michio Kaku wrote in his Physics of the Future how Kurzweil told him that he hoped to see the evidence of the technological singularity in the night sky:

“Kurzweil once told me that when he gazes at the distant stars at night, perhaps one should be able to see some cosmic evidence of the singularity happening in some distant galaxy. With the ability to devour or rearrange whole star systems, there should be come footprint left behind by this rapidly expanding singularity.”

Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100, Michio Kaku, 2011, Chapter 2, Future of AI: Rise of the Machines, p. 102

I have been rather critical of Kurzweil in other posts, but in this, he is correct: if anything like the technological singularity took place in the form that its expositors have given to it, we should be able to see portions of the cosmos transformed under the aspect of intelligence — sub specie intellectus.

Since this is precisely what we do not see, this constitutes a further example of what I recently called SETI as a Process of Elimination: as the scope and sophistication of our search for extraterrestrial intelligence increases over time, and we continue to fail to find evidence of the same, in true inductive fashion this does not mean that we have proved that extraterrestrial intelligence and civilization does not exist, but we can exclude it from certain areas that have been searched, and the more we search the more regions of the cosmos can be declared free of peer civilizations. However, a single counter-example would be sufficient to falsify an inductive generalization possessing only a degree of confirmation and not deductive certitude.

In the case of the technological singularity, with its ability to reproduce itself and improve itself with each generation, thus issuing in escalating and even exponential growth, the “footprint” of obvious intelligent order wherever a technological singularity has emerged in the universe ought to be prominent and rapidly growing. We can say of intelligent machines as Fermi said of aliens: Where are they?

In the formulations of the some of the expositors of the technological singularity the effects of the singularity sound frighteningly similar to Stalinist gigantism, and if this is the case then the footprint of a technological singularity ought to be as visible as an enormous and vulgar Palace of the Soviets — a beacon to the cosmos of the paradise of the machines. Of course, machines may have better taste than earth-bound tyrannies.

An important note: in the bigger picture, the emergence of intelligence as the result of natural processes (as has happened on the earth) is itself a natural process, and the order the intelligence imposes upon its environment is as “natural” as that intelligence itself. However, we know that naturally occurring forms of order differ strikingly from forms of order imposed by intelligence. We know this intuitively, but it is extraordinarily difficult to give an explicit account of it.

If you travel to an unfamiliar place and look out over the landscape, you will likely know immediately whether or not other human beings make their home there: the presence of human habitation alters the landscape. Also, most of us are familiar with what wilderness looks like, and it does look anything like civilization.

Exactly what the difference is between what we might call organic forms of order on the one hand, and on the other hand mechanistic forms of order, however obvious it may be on an intuitive level, is something that we might reasonably expect from a philosophy of technology.

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Closest neighboring stars to our sun.

Seth Shostak, one of the most eminent SETI researchers, has suggested (in his lectures for The Teaching Company) that the Principle of Mediocrity can be extended beyond the idea that there are no privileged perspectives and therefore nothing unusual or exceptional about our solar system, our planet, or even life on earth, to embrace the idea that there is nothing unusual or exceptional about intelligent life, civilization, and the emergence of the industrial technology that makes SETI possible. I should also note in this context that this extension of the Principle of Mediocrity is thoroughly consonant with the argument that I made in The Continuity of Civilization and Natural History.

In several recent posts I have written about Paul Davies’ book The Eerie Silence: Renewing Our Search for Alien Intelligence (e.g., Silent Worlds, Empty Worlds). Paul Davies’ perspective represents what Davies calls “new SETI” in contradistinction to “old SETI,” which is represented by Shostak. We can recast the distinction between old and new SETI a bit by characterizing the traditional SETI undertaking of listening for alien radio broadcasts or sending our own radio signals out into space as a narrowly conceived search for peer civilizations to our own.

Under this interpretation, the traditional SETI undertaking can be seen as a process of elimination, and this process of elimination extends back into history before radio technology. Before our technology gave us the level of knowledge that we have of Mars today, it was widely speculated that there might be a technological civilization on Mars. There have been several proposals for what has generally been called extraterrestrial signaling before radio technology. Karl Friedrich Gauss, the great mathematician, suggested laying out a diagram of the Pythagorean Theorem in the wilderness of Siberia, with appropriately contrasting colors of vegetation. Joseph Johann Littrow suggested flaming trenches carved into the Sahara desert as a way to signal the inhabitants of Mars. Neither scheme was pursued.

Subsequent technological advances have made it possible for us to eliminate the possibility of a peer technological civilization within our solar system. While we cannot yet rule out the possibility of life deep within the aquifers of Mars or in the ocean postulated to exist under the ice of Europa, any life that would exist under these conditions would not have given rise to industrial-technological development.

Traditional SETI searches for alien radio signals have, by this time, similarly extended the process of elimination of peer civilizations from nearby stars. That is to say, however disappointing it is for folks like me, we can say with a high degree of confidence that there are no peer industrial-technological civilizations associated with the nearest stars pictured in the diagram above. Had there been a radio-capable peer civilization on a planet orbiting Barnard’s Star, for instance, it would only take six years for a radio signal to reach us, and another six years for that civilization to receive our answer. While that rate of communication is slow compared to our familiar modes of communication, since we’ve been broadcasting our signals for more than a hundred years there has been plenty of time to send and receive several messages. Similar considerations hold for all the stars within a radius of the reach of our radio signals, which radius is now a little larger than a hundred light years.

Of course, we could receive a signal from Barnard’s Star tomorrow, of an only-just-recently radio-capable civilization, but we have other reasons now (lack of extra-solar planets, for instance, and being a red dwarf star) for eliminating other local stars as homes for peer civilizations. This does not eliminate the possibility of non-peer civilizations, which could include either non-radio capable civilizations (like the quasi-neolithic alien societies in the film Avatar) or civilizations so different from our own that we could not recognize them as peers to our particular species of technological civilization.

As our technology improves, it extends the traditional SETI task of the process of elimination farther and farther into the cosmos. It has been this gradually increasing range of technology and the implicit process of elimination that has gotten SETI researchers to thinking and coming up with the ideas that are part of what Davies calls new SETI. Similar considerations hold for the discovery of peer life, even if not intelligent or civilized life. By “peer life” I mean life more or less biologically similar to what we know on earth. The arrival of the Viking landers on Mars largely discounted the possibility of peer life on Mars, although, as I wrote above, there remains the possibility of luxuriant caves buried deep beneath the Martian surface, heated by the residual heat of the molten core. The imagination quickly jumps to visions like those of Journey to the Center of the Earth in contemplating such a scenario. But even this scenario will eventually be either confirmed or disconfirmed by science.

Exobiology and astrobiology are sciences uniquely dependent upon technology. Technological advances brought these sciences into being, and only further technological advances will be able to settle the questions posed by nascent exobiology and astrobiology. For example, when we become able to take spectra from the atmosphere of earth-like planets orbiting other stars — a technological possibility within the next few decades — we would be able to determine the presence of certain kinds of life on other planets, even if that life has not produced a technological civilization that could communicate after the fashion of traditional SETI assumptions.

As far as technological innovation, as well as scientific ingenuity, has pushed the SETI process of elimination outward, the bubble of the extent of our knowledge is still quite small in the galaxy. The map of our spiral arm within the Milky Way galaxy, showing cepheid variable stars as “light houses” in the cosmos, includes a scale that shows a thousand light years in the lower right hand corner. By this scale you can judge by eye a sphere of a hundred light years radius which is our “radio bubble” in the cosmos. As you can see, there remains plenty of space even in our nearest cosmic “neighborhood” for peer civilizations from which we have not heard, and which would not have had an opportunity to hear from us. And this is just the Milky Way. There are galaxies in the cosmos like stars in the Milky Way: almost too many to comprehend. Most of these will remain beyond our scientific knowledge except in the most abstract and schematic form of knowledge. Radical developments and departures in science would be necessary for human technological civilization, however far extended in space, to make an adequate survey of the universe and extend even the traditional SETI process of elimination to a statistically significant percentage of the universe.

However, although our scientific sample of the universe is very small in comparison to the whole, if the Principle of Mediocrity holds good, it is a valid sample. That is something to think about. If we could produce a rigorous and comprehensive statement of the principle of mediocrity, we would have a better idea of what exactly is eliminated by the SETI process of elimination.

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Grand Strategy Annex

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A Question of Absence:

The Eerie Silence: Renewing Our Search for Alien Intelligence, Paul Davies

A Meditation on SETI

At present I am listening to The Eerie Silence: Renewing Our Search for Alien Intelligence by Paul Davies. I’m only a little more than half way through the book so far, so while I have much more to say on the book, I’ll reserve more extensive remarks until I’ve gotten through more of it.

For the time being, I will content myself with some brief remarks on the central theme of the book. This theme is emptiness, silence, absence, lack, privation, nothingness…

Are we alone?

The eerie silence is the deafening nothingness that has greeted those SETI scientists listening among the stars for extraterrestrial radio signals. They haven’t heard anything in fifty years. Some in the discipline are having second thoughts, and these second thoughts have largely inspired this book. Davies describes the difference between “old” SETI and “new” SETI, the latter being an attempt to think through, and hopefully go beyond, the presuppositions of the original SETI research program.

Davies’ book is fairly comprehensive, so he takes the reader through much familiar material, such as Fermi’s Paradox — which asks of any extraterrestrial intelligence, “Where are they?” — which leads immediately to the equally familiar refrain, absence of evidence is not evidence of absence.

Let us, for the moment, grant the SETI skeptics the argument, if only hypothetically, and ask what kind of galaxy we live in, if we live in it quite alone.

Suppose we are alone, or nearly alone. What then? Then the cosmos is filled with empty worlds, silent worlds. It is an odd feeling simply to know this. Our bustling planet is a loud place, filled with noises. Arthur Schopenhauer wrote a justly famous short essay, “On Noise” which begins with the following paragraph:

“Kant wrote a treatise on The Vital Powers. I should prefer to write a dirge for them. The superabundant display of vitality, which takes the form of knocking, hammering, and tumbling things about, has proved a daily torment to me all my life long. There are people, it is true — nay, a great many people — who smile at such things, because they are not sensitive to noise; but they are just the very people who are not sensitive to argument, or thought, or poetry, or art, in a word, to any kind of intellectual influence. The reason of it is that the tissue of their brains is of a very rough and coarse quality. On the other hand, noise is a torture to intellectual people. In the biographies of almost all great writers, or wherever else their personal utterances are recorded, I find complaints about it; in the case of Kant, for instance, Goethe, Lichtenberg, Jean Paul; and if it should happen that any writer has omitted to express himself on the matter, it is only for want of opportunity.”

Though Schopenhauer is remembered to philosophical history as a pessimist, he could be a very amusing writer, and this brief essay offers an excellent display of his wit and charm.

If the Milky Way is empty of intelligent life except for us, it is empty of that particular variety of noise that Schopenhauer protested. Schopenhauer specifically mentioned “knocking, hammering, and tumbling things about,” which is more or less synonymous with the activities of early industrial civilization. Schopenhauer quotes Thomas Hood as saying of the Germans, “For a musical nation, they are the most noisy I ever met with.” Schopenhauer attributes this to the obtuseness of mind of his people, but I think this is rather a universal, or nearly universal, condition of civilization, and a condition that is heightened by industrialization.

An empty universe would be a marvelous place for silent meditation and contemplation, interrupted by only the soothing sounds of nature in its various forms. How far would these forms of nature extend in a universe empty of intelligent life? This is perhaps more interesting and promising question than appears at first.

The rare earth hypothesis, upon which the empty universe is predicated, involves a suspension of the principle of mediocrity, which in some formulations is essentially the same thing as the Copernican Principle. If the kind of life, intelligence, and technological civilization that we have here on the earth is a rare event, and perhaps a unique event, then the earth and the civilization that it hosts is in no sense mediocre, but is the exception to many rules.

In several posts I have noted how our expanding knowledge of the universe has only pointed toward confirmation of the Copernican Principle. For example, in More Evidence for the Copernican Principle I argued that the discovery of extrasolar planets in the Helmi Stream extends the Copernican Principle to other galaxies, since the Helmi Stream associated with the Milky Way is the remnant of a captured galaxy once separate from the Milky Way.

Earlier, in Other Worlds, I wrote the following:

“…claims to cosmic uniqueness are being disproved as soon as the technological means are available to disprove them. For example, there is a large and growing body of evidence on extrasolar planets. We now know for a fact that there are planetary systems other than our own. Since we already know that planetary atmospheres are not unique (from the example of Mars, Venus, and several planetary moons), and we know from the moons of Jupiter that volcanic activity is not unique to the earth, it would be foolish to suppose that these extrasolar planets are all without atmospheres, and if they are small, rocky planets, they will be, like Mars, places not unlike the earth. And among these places not unlike the earth, there will be very interesting places, beautiful places, places unique in their own way, and well worth seeing. It is entirely reasonable to want to see such places quite apart from the question of whether there is life or whether such places are inhabited by sentient creatures or civilizations.”

These worlds upon which I speculated would not be silent, but they would not have noise in the Schopenhauerian sense. What sounds would they have? As near to us as Mars, if we could listen through the suits that would be necessary to survive on the surface, we could hear the Martian wind whistling among the dead rocks and stones on the Martian desert. The shifting sands of Mars might also produce the phenomenon of “singing sands” known on earth, though these would be the singing sands of Mars — plaintive, alien sounds of an alien world.

Farther afield than Mars, since we now can prove that there are extrasolar planets, and recent technological improvements have yielded smallish, rocky planets within the habitable zones of stars, there may be alien worlds with water, perhaps even entire oceans. Water in lakes, ponds, streams, waterfalls and oceans would make sounds. A waterfall can be nearly deafening if you are close to it, as can the tide washing upon the shore.

This last example, the sound of the tide, points to the interesting fact that the earth has one large moon. If we had no moon, the oceans would be attracted by the gravity of more distant celestial bodies, but this would not likely be sufficient to create the tides we know. If the earth had several moons, or much smaller moons, again we would not have the familiar tides. The sound of the tides would vary according to the gravitational environment of the ocean in question. It would be a definitely odd experience to stand on the shore of an alien ocean moved by no tides at all. In fact, the effect might be so dramatic that a person might want to travel there simply to experience this uniquely contemplative environment.

If we add into the picture further elements, in line with the principle of mediocrity but not fully violating the rare earth hypothesis that leaves us stranded alone in the Milky Way, there may be worlds — empty worlds, nearly silent worlds — in which the only sound to be heard is the wind in the grasses and the trees. Or, if there is animal life as well, the sounds of wings, and the clicks and chirps of insects. If you have ever been in the Amazon at night, you know that the ambient sound is almost as deafening as a waterfall, a torrent of white noise produced by countless organisms going about the ordinary business of life, but once again this is not Schopenhauerian noise.

If you had the leisure to listen long enough in any of these environments, you would hear periodicities in the ambient sound — diurnal periods, seasonal periods, annual periods, and perhaps also periodicities governed by unique forms of life.

These silent, empty worlds would only be silent and empty in so far as we identify meaningful sounds with human activity, which seems to me to be the antithesis of the spirit of SETI. No natural scientist would suppose for a moment that a world without “noise” would be a world without interest. One of the most surprising claims I found in Davies’ book was this:

“If there is somebody at the destination planet already, then why bother to make the trip? If the purpose of space travel is exploration, well, the aliens can send us the content of their latest DVD. On the other hand, if it is conquest, then the fact that the target planet already has a far more advanced civilization ensconced would constitute a pretty strong deterrent. All in all, it would make more sense for the newcomer civilization to stay put and simply join the Galactic Club.”

Paul Davies, The Eerie Silence: Renewing Our Search for Alien Intelligence, pp. 119-120

In this context, Davies doesn’t even consider the kind of motivations that inspire people to climb mountains, though just a few pages after this quote he considers these motivations in a different context.

Exploration is about much more than knowing what it out there. It is also about experiencing what is out there, and even touching what is out there. While there will always be some people content to know, just as there are always some people content with ignorance, there will also always be people who want to go and see for themselves, and this motivation will not be dampened by the possibility that there are no other technological civilizations in the Milky Way. The Cosmic wilderness awaits us.

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