Searching the Sky

21 November 2013



When Frank Drake first formulated the eponymously-named Drake equation the number of planetary systems in the universe (the second term in the Drake equation, fp) was an unknown among other unknowns. Now we are rapidly approaching a scientifically-based quantification of this once unknown number. We now know that planetary systems are common, and moreover that planetary systems with smallish, rocky planets in the habitable zones of stars are relatively common. (Cf., e.g., Earth-Like Worlds “Very Common”)

Frank Drake

As soon as we reached a level of technological and scientific expertise that made the search for exoplanets practical, we began to find them. The most recent exoplanet discoveries, and the recent announcement that planets and planetary system are common, are primarily due to the NASA Kepler mission. According to the NASA website, the Kepler mission was…

“…specifically designed to survey a portion of our region of the Milky Way galaxy to discover dozens of Earth-size planets in or near the habitable zone and determine how many of the billions of stars in our galaxy have such planets.”

In this, the Kepler mission has been wildly successful. But in order to get to the point at which our civilization could conceive, design, build, and operate the Kepler mission we had to pass through thousands of years of development, and before our civilization developed to its current state of technological prowess, it took terrestrial biology billions of years of development to arrive at organisms capable of creating a civilization that could develop to this level.

Kepler neighborhood

Contrast the experience of Kepler’s exoplanet search with the experience of SETI, the search for extraterrestrial intelligence. What did not happen as soon as we began searching for SETI signals? We did not immediately begin hearing a whole range of intelligent extraterrestrial signals, which would have been a result parallel to the immediate successes of the exoplanet search (immediate, that is, in the technological zone of proximal development). Both Kepler and SETI are searches of the sky. The Kepler mission gave nearly immediate results; Frank Drake conducted the first SETI study in 1960. Drake found only an eerie silence, and ever since we have only heard an eerie silence. Once the technological threshold of exoplanet search was reached, the search immediately discovered its object, but once the technological threshold of SETI was reached, the search revealed nothing.


Please understand that, in making this observation, I am in no sense criticizing SETI efforts; I am not saying that SETI is a waste of effort, or a waste of money; I am not saying that SETI is wrongheaded or that it is not a science. On the contrary, I think SETI is interesting and important, and that includes the fact that SETI has found only an eerie silence — this is in itself important and interesting. We have discovered radio silence, except for natural sources. This tells us something about the universe. If there were a truly predatory peer civilization in our region of the Milky Way, it would be expected that they would go to the trouble to broadcast their presence to the universe, in hope of luring unsuspecting peer civilizations. Like Odysseus having himself strapped to the mast of his ship so that he could hear the song of the Sirens while his crew rowed on oblivious, their ears stopped with wax, we would have to listen to such signals restraining ourselves from rushing toward that fatal lure.

Don't expect to find anything like this close to home.

Don’t expect to find anything like this close to home.

What we now know, as a result of SETI’s discovery of the eerie silence, is that METI (messaging extraterrestrial intelligence) beacons are not common. If METI beacons were common in the Milky Way, we would have heard them by now. There may yet be METI beacons, but they are not the first thing that you hear when you begin a SETI program (unlike looking for exoplanets and finding them as soon as you have the capability of looking). If METI beacons exist, they are rare and difficult to find. I think we can go further than this, and assert with some degree of confidence that there is no alien “super-civilization” in our galactic neighborhood constructing vast mega-engineering projects and pumping out high-power EM spectrum emissions that would be easily detectable by any technological civilization that suddenly had the idea to begin listening for such signals.

James Benford has argued that METI beacons entail prohibitive expense, and has argued against unregulated terrestrial METI efforts.

James Benford has argued that METI beacons entail prohibitive expense, and has argued against unregulated terrestrial METI efforts.

I wrote above that SETI and exoplanet searches are sensitive to a technological threshold. We passed the SETI threshold in the 1960s, and we have passed the exoplanet search threshold in the first decade of the twenty-first century. There is a further technological threshold, which is also an economic threshold — the ability to detect the unintentional EM spectrum radiation “leakage” from technological civilizations that have not had the interest or the resources to establish a METI beacon, but which, like us, are radiating EM spectrum signals as an epiphenomenal expression of our industrial-technological civilization. I say that this is also an economic threshold, as James Benford and colleagues have taken pains to point out the expense associated with establishing a METI beacon. (This is something I discussed in my Centauri Dreams post SETI, METI, and Existential Risk; James Benford responded on Centauri Dreams with James Benford: Comments on METI; my post on Centauri Dreams, along with responses from Benford and from David Brin, received quite a few comments, so if the reader is interested, it is worthwhile to follow the links and read the ensuing discussion.)


If METI is “shouting to the galaxy” (as James Benford put it), then the unintentional leakage of EM spectrum radiation of industrial-technological civilization is not shouting to the galaxy but rather whispering to the cosmos, and in order to be able to hear a whisper we must listen intently — holding our breath and putting a hand to our ear. Whether or not we choose to listen intently for whispers from the cosmos, we have not yet reached the developmental stage of civilization in which this is practical, though we seem to be moving in that direction. If we should continue the trajectory of our technological development — which, as I see it, entails both increasing automation and routine travel between Earth and space — such an effort will be within our grasp within the coming century.


Advanced industrial-technological civilizations will, by definition, know much more than we know. Their science will be commensurate with their technology and their engineering, since their civilization, if it is an industrial-technological peer civilization (and in so far as industrial-technological civilization is defined by the STEM cycle, which I believe to be the case), will experience the advance of science joined inseparably to the advance of technology and engineering. What would they do with this epistemic advantage? Such an epistemic advantage presents the possibility of SETI and METI asymmetry. We have an asymmetrical advantage over civilizations at an earlier stage of development, as older industrial-technological civilizations would have an asymmetrical advantage over us, with the ability to find us while concealing themselves.

A Pythagorean geoglyph based on Gauss' idea for signaling to ETI.

A Pythagorean geoglyph based on Gauss’ idea for signaling to ETI.

The developmental direction of industrial-technological civilization as defined by the STEM cycle means that any advanced industrial-technological civilization will be “backward compatible” with earlier forms of technological communication. We might not (yet) be able to build a quantum entanglement transmitter in order to communicate instantaneously over cosmic distances (even though we can conceive the possibility), but an advanced peer civilization will be able to listen for our EM spectrum radiation leakage, in the same way that we today could continue to look for signs of ETI compatible with earlier stages of industrial-technological civilization. Karl Friedrich Gauss suggested geometrical shapes laid out in wheat in the wastes of Siberia to get the attention of extraterrestrials, while Joseph von Littrow suggested trenches filled with burning oil in the Sahara. Interesting in this context, although our civilization had the technology to pursue these methods, no one undertook them on a large scale.

civilizational ZPD

When, in the future, we have the ability to image the surface of exoplanets with large extraterrestrial telescopes, we could look for such attempted signals within the capability of less developed civilizations to produce, such as those suggested by Gauss and Littrow. But when it comes to advanced peer civilizations, we don’t have the knowledge to know what to look for. The more advanced the civilization, the farther it lies beyond our civilizational zone of proximal development (ZPD), but the more advanced a civilization the earlier it would have to have its origins in the history of the universe, and at some point in the development of the universe (going backward in time to the origins of the universe) it would not be possible for an industrial-technological civilization to emerge because if we go far enough back in time, the elements necessary to an industrial-technological civilization do not yet exist. So there seems to be a window of development in the history of the universe for the emergence of industrial-technological civilizations. This strikes me as a non-anthropocentric way of expressing one formulation of the anthropic cosmological principle (and an idea worth developing further, since I have been searching for a formulation of the anthropic cosmological principle worthy of the name).

In an optimistic assessment of our place in the universe, we could hope that any substantially more advanced civilization could serve as the “more knowledgeable other” (MKO) that would facilitate our progress through the civilizational zone of proximal development.

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Grand Strategy Annex

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These galaxies would certainly gain the mythological attention of any sentient beings living in full view of such spectacular displays.

When a future science of civilizations begins to take shape, it will need to distinguish broad categories or families of civilizations, or, if you will, species of civilizations. In so far as civilizations are out outgrowth of biological species, they are an extension of biology, and it is appropriate to use the terminology of species to characterize civilizations.

Just a few days ago in A Copernican Conception of Civilization I distinguished between eocivilization (i.e., terrestrial civilizations), exocivilization (extraterrestrial civilizations), and astrocivilization (an integrated conception of eo- and exocivilization taken together). This is a first step in identifying species of civilizations.

Given that astrocivilization follows directly from (one could say, supervenes upon) astrobiology, it is particular apt to extend the definition of astrobiology to astrocivilization, and so in A Copernican Conception of Civilization I paraphrased the NASA definition of astrobiology, mutatis mutandis, for civilization. Thus astrociviliation comprises…

…the study of the civilized universe. This field provides a scientific foundation for a multidisciplinary study of (1) the origin and distribution of civilization in the universe, (2) an understanding of the role of the structure of spacetime in civilizations, and (3) the study of the Earth’s civilizations in their terrestrial and cosmological context.

Some time ago in A First Image from the Herschel Telescope I made the suggestion that particular physical features of a galaxy might result in any and all civilizations arising within that galaxy to share a certain feature or features based upon the features of the containing galaxy. This is a point worth developing at greater length.

Of the images of the M51 galaxy I wrote:

If there are civilizations in that galaxy, they must have marvelous constellations defined by these presumably enormous stars, and that one star at the top of the image seems to be brighter than any other in that galaxy. It would have a special place in the mythologies of the peoples of that galaxy. And the peoples of that galaxy, even if they do not know of each other, would nevertheless have something in common in virtue of their relation to this enormous star. We could, in this context, speak of a “family” of civilizations in this galaxy all influenced by the most prominent stellar feature of the galaxy of which they are a part.

We can generalize about and extrapolate from this idea of a family of civilizations defined by the prominent stellar features of the galaxy in which they are found. If a galaxy has a sufficiently prominent physical feature that can witnessed by sentient beings, these features will have a place in the life of these sentient beings, and thus by extension a place in the civilizations of these sentient beings.

There is a sense in which it seems a little backward to start from the mythological commonalities of civilizations based upon their view of the cosmos, but it is only appropriate, because this is where cosmology began for human beings. If we remain true to the study of astrocivilization as including, “the search for evidence of the origins and early evolution of civilization on Earth,” the origins and early evolution of civilization on earth was at least in part derived from early observational cosmology. We began with myths of the stars, and it is to be expected that many if not most civilizations will begin with myths of the stars. Moreover, these myths will be at least in part a function of the locally observable cosmos.

The more expected progress of thought would be to start with how the physical features of a particular galaxy or group of galaxies would affect the physical chemistry of life within this galaxy or these galaxies, and how life so constituted would go on to constitute civilization. These are important perspectives that a future science of civilizations would also include.

Simply producing a taxonomy of civilizations based on mythological, physical, biological, sociological, and other factors would only be the first step of a scientific study of astrocivilization. As I have noted in Axioms and Postulates in Strategy, Carnap distinguished between classificatory, comparative, and quantitative scientific concepts. Carnap suggested that science begins with classificatory conceptions, i.e., with a taxonomy, but must in the interests of rigor and precision move on to the more sophisticated comparative and quantitative concepts of science. More recently, in From Scholasticism to Science, I suggested that these conceptual stages in the development of science may also demarcate historical stages in the development of human thought.

It will only be in the far future, when we have evidence of many different civilizations, that we will be able to formulate comparative concepts of civilization based on the actual study of astrocivilization, and it is only after we have graduated to comparative concepts in the science of astrocivilization that we will be able to formulate quantitative measures of civilization informed by the experience of many distinct civilizations.

At present, we know only the development of civilizations on the earth. This has not prevented several thinkers from drawing general conclusions about the nature of civilization, but it is not enough of a sample to say anything definitive about, “the origin, evolution, distribution, and future of civilization in the universe.” The civilizations of the earth represent a single species, or, at most, a single genera of civilization. We will need to study the independent origins and development of civilization in order to have a valid basis of comparison. We need to be able to see civilization as a part of cosmological evolution; until that time, we are limited to a quasi-Linnaean taxonomy of civilization, based on observable features in common; after we have a perspective of civilization as part of cosmological evolution, it will be possible to formulate a more Darwinian conception.

In the meantime, while we can understand theoretically the broad outlines of a study of astrocivilization, the actual content of such a science lies beyond our present zone of proximal development. And taking human knowledge in its largest possible context, we can see that our epistemic zone of proximal development supervenes on the maturity and extent of the civilization of which we are a part. This does not hold for more restricted forms of knowledge, but for forms of knowledge of which the study of astrocivilization is an example (i.e., human knowledge at its greatest extent) it becomes true. Not only individuals, but also whole societies and entire civilizations have zones of proximal development. A particular species of civilization facilitates a particular species of knowledge — but it also constrains other species of knowledge. This observation, too, would belong to an adequate conception of astrocivilization.

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Grand Strategy Annex

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Jean Piaget

One of the important ideas from Piaget’s influential conception of cognitive development is that of perspective taking. The ability to coordinate the perspectives of multiple observers of one and the same state of affairs is a cognitive skill that develops with time and practice, and the mastery of perspective taking coincides with cognitive maturity.

From a philosophical standpoint, the problem of perspective taking is closely related to the problem of appearance and reality, since one and the same state of affairs not only appears from different perspectives for different observers, it also appears from different perspectives for one and the same observer at different times. In other words, appearance changes — and presumably reality does not. It is interesting to note that developmental psychologists following Paiget’s lead have in fact conducted tests with children in order to understand at what stage of development they can consistently distinguish between appearance and reality.

Just as perspective taking is a cognitive accomplishment — requiring time, training, and natural development — and not something that happens suddenly and all at once, the cognitive maturity of which perspective taking is an accomplishment does not occur all at once. Both maturity and perspective taking continue to develop as the individual develops — and I take it that this development continues beyond childhood proper.

While I find Piaget’s work quite congenial, the developmental psychology of Erik Erikson strikes me as greatly oversimplified, with its predictable crises at each stage of life, and the implicit assumption built in that if you aren’t undergoing some particular crisis that strikes most people at a given period of life, then there is something wrong with you; you ought to be experiencing the right crisis at the right time. That being said, what I find of great value in Erikson’s work is his insistence that development continues throughout the human lifespan, and does not come to a halt after a particular accomplishment of cognitive maturity is achieved.

Piagetian cognitive development in terms of perspective taking can easily be extended throughout the human lifespan (and beyond) by the observation that there are always new perspectives to take. As civilization develops and grows, becoming ever more comprehensive as it does so, the human beings who constitute this civilization are forced to formulate ever more comprehensive conceptions in order to take the measure of the world being progressively revealed to us. Each new idea that takes the measure of the world at a greater order of magnitude presents the possibility of a new perspective on the world, and therefore the possibility of a new achievement in terms of perspective taking.

The perspectives we attain constitute a hierarchy that begins with the first accomplishment of the self-aware mind, which is egocentric thought. Many developmental psychologists have described the egocentric thought patterns of young children, though the word “egocentric” is now widely avoided because of its moralizing connotations. I, however, will retain the term “egocentric,” because it helps to place this stage within a hierarchy of perspective taking.

The egocentric point of departure for human cognition does not necessarily disappear even when it is theoretically surpassed, because we know egocentric thinking so well from the nearly universal phenomenon of human selfishness, which is where the moralizing connotation of “egocentric” no doubt has its origin. An individual may become capable of coordinating multiple perspectives and still value the world exclusively from the perspective of self-interest.

In any case, the purely egocentric thought of early childhood confines the egocentric thinker to a tightly constrained circle defined by one’s personal perspective. While this is a personal perspective, it is also an impersonal perspective in so far as all individuals share this perspective. It is what Francis Bacon called the “idols of the cave,” since every human being, “has a cave or den of his own, which refracts and discolours the light of nature.” This has been well described in a passage from F. H. Bradley made famous by T. S. Eliot, because the latter quoted it in a footnote to The Waste Land:

“My external sensations are no less private to myself than are my thoughts or my feelings. In either case my experience falls within my own circle, a circle closed on the outside; and, with all its elements alike, every sphere is opaque to the others which surround it… In brief, regarded as an existence which appears in a soul, the whole world for each is peculiar and private to that soul.”

F. H. Bradley, Appearance and Reality, p. 346, quoted by T. S. Eliot in footnote 48 to The Waste Land, “What the Thunder Said”

I quote this passage here because, like my retention of the term “egocentric,” it can help us to see perspectives in perspective, and it helps us to do so because we can think of expanding and progressively more comprehensive perspectives as concentric circles. The egocentric perspective is located precisely at the center, and the circle described by F. H. Bradley is the circle within which the egocentric perspective prevails.

The next most comprehensive perspective taking beyond the transcendence of the egocentric perspective is the transcendence of the ethnocentric perspective. The ethnocentric perspective corresponds to what Bacon called the “idols of the marketplace,” such that this perspective is, “formed by the intercourse and association of men with each other.” The ethnocentric perspective can also be identified with the sociosphere, which I recently discussed in Eo-, Eso-, Exo-, Astro- as an essentially geocentric conception which, in a Copernican context, should be overcome.

Beyond ethnocentrism and its corresponding sociosphere there is ideocentrism, which Bacon called the “idols of the theater,” and which we can identify with the noösphere. The ideocentric perspective, which Bacon well described in terms of philosophical systems, such that, “all the received systems are but so many stage-plays, representing worlds of their own creation after an unreal and scenic fashion.” Trans-ethnic communities of ideology and belief, like world’s major religions and political ideologies, represent the ideocentric perspective.

The transcendence of the ideocentric perspective by way of more comprehensive perspective taking brings us to the anthropocentric perspective, which can be identified with the anthroposphere (still a geocentric and pre-Copernican conception, as with the other -spheres mentioned above). The anthropocentric perspective corresponds to Bacon’s “idols of the tribe,” which Bacon described thus:

“The Idols of the Tribe have their foundation in human nature itself, and in the tribe or race of men. For it is a false assertion that the sense of man is the measure of things. On the contrary, all perceptions as well of the sense as of the mind are according to the measure of the individual and not according to the measure of the universe. And the human understanding is like a false mirror, which, receiving rays irregularly, distorts and discolours the nature of things by mingling its own nature with it.”

Bacon was limited by the cosmology of his time so that he could not readily identify further idols beyond the anthropocentric idols of the (human) tribe, just as we are limited by the cosmology of our time. Yet we do today have a more comprehensive perspective than Bacon, we can can identify a few more stages of more comprehensive perspective taking. Beyond the anthropocentric perspective there is the geocentric perspective, the heliocentric perspective, and even what we could call the galacticentric perspective — as when early twentieth century cosmologists argued over whether the Milky Way was the only galaxy and constituted an “island universe.” Now we know that there are other galaxies, and we can be said to have transcended the galacticentric perspective.

As I wrote above, as human knowledge has expanded and become more comprehensive, ever more comprehensive perspective taking has come about in order to grasp the concepts employed in expanding human knowledge. There is every reason to believe that this process will be iterated indefinitely into the future, which means that perspective taking also will be indefinitely iterated into the future. (I attempted to make a similar and related point in Gödel’s Lesson for Geopolitics.) Therefore, further levels of cognitive maturity wait for us in the distant future as accomplishments that we cannot yet attain at this time.

This last observation allows me to cite one more relevant developmental psychologist, namely Lev Vygotsky, whose cognitive mediation theory of human development makes use of the concept of a Zone of proximal development (ZPD). Human development, according to Vygotsky, takes place within a proximal zone, and not at any discrete point or stage. Within the ZPD, certain accomplishments of cognitive maturity are possible. In the lower ZPD there is the actual zone of development, while in the upper ZPD there lies the potential zone of development, which can be attained through cognitive mediation by the proper prompting of an already accomplished mentor. Beyond the upper ZPD, even if there are tasks yet to be accomplished, they cannot be accomplished within this particular ZPD.

With the development of the whole of human knowledge, we’re on our own. There is no cognitive mediator to help us over the hard parts and assist us in the more comprehensive perspective taking that will mark a new stage of cognitive maturity and possible also a new zone of proximal development in which new accomplishments will be possible. But this has always been true in the past, and yet we have managed to make these breakthroughs to more comprehensive perspectives of cognitive maturity.

I hope that the reader sees that this is both hopeful and sad. Hopeful because this way of looking at human knowledge suggests indefinite progress. Sad because we will not be around to see the the accomplishments of cognitive maturity that lie beyond our present zone of proximal development.

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Grand Strategy Annex

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