The Terrestrial Eocivilization Thesis

Wednesday

---

A Thesis in the Theory of Civilization

Not long ago in Eo-, Eso-, Exo-, Astro- I discussed how Joshua Lederberg’s distinctions between eobiology, esobiology, and exobiology can be used as a model for the concepts of eocivilization, esocivilization, and exocivilization, all of which are anterior to the more comprehensive conception of astrocivilization (like the more comprehensive conception of astrobiology).

My post on Eo-, Eso-, Exo-, Astro- was in part a correction to my earlier post Eo-, Eso-, Astro-, in which I had contrasted eobiology to exobiology, when I should have been contrasting esobiology to exobiology.

I had derived the contrast of eobiology and exobiology from Steven J. Dick and James E. Strick’s excellent book The Living Universe: NASA and the Development of Astrobiology, in which they cite Lederberg’s contrast of these terms. I had initially drawn the wrong contrast between the two concepts. When I started to read Lederberg’s writings, I realized that Lederberg was making a dramatic contrast between the scientific study of origins and the scientific study of destiny, rather than the contrast I expected. However, the contrast I originally drew remains a valid schema for understanding the comprehensive conception of astrobiology — and, by extension, the comprehensive conception of astrocivilization.

Astrobiology may be understood as the integration of esobiology — our biology, terrestrial biology — and exobiology — biology not of the Earth — into a comprehensive whole that places life in a cosmological context. Parallel to this, I define astrocivilization as the integration of esocivilization — our civilization, terrestrial civilization — and exocivilization — civilization not of the Earth — into a comprehensive whole that places civilization in a cosmological context. These concepts are not merely parallel, but the parallel between concepts of biology and concepts of civilization follows from a naturalistic conception of civilization as an extension of biology.

Civilization can be understood as a greatly elaborated result of behavioral adaptation. Just as evolutionary gradualism takes us imperceptibly over countless generations from the simple origins of life to the complexity of life we know today, so too evolutionary gradualism in the development of civilization takes us imperceptibly over countless generations from the simplest behavioral adaptations to the complexity of behavioral adaptation that culminates in civilization — and which may well culminate in some further post-civilizational social institution. (We must add this last proviso so as not to be mistaken for advocating some kind of teleological conception of civilization, as one might expect, for example, from strong formulations of the anthropic cosmological principle.)

In reformulating my contrast of eocivilization and exocivilization as the contrast between esocivilization and exocivilization, the term “eocivilization” is freed up to assume its more etymologically accurate meaning, which properly should be “early civilization” (“eo-” coming from the Greek means “early”). This turns out to be a very useful concept, but it always points to an additional thesis in the theory of civilization.

As in astrobiology, in which we study life on Earth as a clue to life in the cosmos, so too in astrocivilization we study civilization on Earth as a clue to civilization in the universe. Life on Earth is the only life that we know of, and civilization on the Earth is the only civilization that we know of, but in so far as we approach life and civilization from the scientific perspective of methodological naturalism, we do not assume that these are necessarily the only instances of life or of civilization in the cosmos. There may be other instances of life and civilization of which we simply know nothing.

In light of the possibility of life and civilization elsewhere in the universe, but our only knowledge of civilization being terrestrial civilization, I will call the terrestrial eocivilization thesis the position that identifies early civilization, i.e., eocivilization, with terrestrial civilization. In other words, our terrestrial civilization is the earliest civilization to emerge in the cosmos. Thus the terrestrial eocivilization thesis is the civilizational parallel to the rare earth hypothesis, which maintains, contrary to the Copernican principle, that life on earth is rare. I could call it the “rare civilization hypothesis” but I prefer “terrestrial eocivilization thesis.”

It is possible to further distinguish between the position that terrestrial civilization is the first and earliest civilization in the cosmos, and the position that terrestrial civilization is unique and the sole source of civilization in the cosmos. There may be exocivilizations that have and will emerge after terrestrial civilization, meaning that there are several sources of civilization in the cosmos, but that terrestrial civilization is the earliest to emerge. Thus the terrestrial eocivilization thesis can be distinguished from the uniqueness of terrestrial civilization. We might call the non-uniqueness of industrial-technological civilization on the Earth the “multi-regional hypothesis” in astrocivilization (to borrow a term from hominid evolutionary biology), but I would prefer to simply call it the “Non-Uniqueness Thesis.”

In the event that human civilization expands cosmologically and is ultimately the source of civilization on exoplanets that are part of other solar systems and perhaps even other galaxies, the terrestrial eocivilization thesis will have more substantive content than it does now at present, when (if the thesis is true) eocivilization is simply identical to all civilization in the cosmos. All we can say at present, however, is that terrestrial civilization is identical to all known civilization in the cosmos. To assert more than this is to assert the terrestrial eocivilization thesis, which is underdetermined and goes well beyond available evidence.

. . . . .

. . . . .

. . . . .

Eo-, Eso-, Exo-, Astro-

Tuesday

---

NASA has published a number of astrobiology graphic novels that are well worth taking a look at.

Last spring in Eo, Exo-, Astro- I discussed the importance of the distinction between eobilogy, exobiology, and astrobiology as representing a truly Copernican conception of the life sciences, as well as the applicability of concepts from astrobiology to the study civilization. This discussion was partly an outgrowth of my continuing work on the idea of spacefaring civilization, which I discussed when I spoke at last year’s 100 Year Starship Study symposium (100YSS). Now that I am preparing to speak at the 2012 100YSS (my topic this year will be “The Large Scale Structure of Spacefaring Civilization”) I have been working on these ideas again and I found a problem with my previous formualtions.

Joshua Lederberg in front of Mars Lander chart, from Profiles in Science, National Library of Medicine

I mentioned in my previous post on this topic the work of Joshua Lederberg, one of the founders of exobiology. I was lead to Lederberg’s work by the excellent book The Living Universe by Steven J. Dick and James E. Strick, which noted how Lederberg had contrasted eobiology and exobiology. I jumped to the conclusion that eobiology and exobiology were contrasted as terrestrial biology to non-terrestrial biology. While I was right about astrobiology being the more comprehensive synthesis, placing terrestrial biology in its cosmological context, I got Lederberg’s contrast of eobiology and exobiology wrong.

Lecture notes of Lederberg for his Cartwright Lecture at Columbia University on18 November 1981.

Joshua Lederberg wrote this about the formation of his ideas in the immediate post-Sputnik period:

At around this time, I coined the term “exobiology”, a smaller mouthful than “the scientific study of extraterrestrial life”. Exobiology has been panned as one of the few scientific disciplines that may have an empty set as its experimental objects. Regardless, what we have called biology until now should be limned “esobiology”, which can be backformed into “earth’s own biology”. It may be unique in the solar system, perhaps even the cosmos — howbeit, it is still parochial.

Joshua Lederberg, Terry Lectures, Yale University, Thurs – Fri: April 6, 7 and April 13, 14, 1989, “Origin and Extent of Life” (Notes for Terry Lecture #1)

Most if not all of Lederberg’s papers are available online, including several early articles in which he formulated his ideas of exobiology before the idea of astrobiology had emerged. The papers available at Profiles in Science are well worth reading.

Lederberg’s contrast between eobiology and exobiology was intended as a contrast between origins of life research and research into life in the universe beyond the earth, and hence beyond eobiology as the origins of biology. There is almost an element of csomological eschatology present in Lederberg’s visionary compass taking in the breadth of life from it earliest origins to its far-flung possibilities in the depths of space. Lederberg called eobiology “the ultimate creation myth of science,” and exobiology might in the same spirit be called the ultimate eschatological myth of science. Here is how Lederberg formulated the distinction between eobiology and exobiology in 1995:

The reconstruction of life’s origin, eobiology, is the ultimate creation myth of science — certainly it places the most stringent demands on the method of science. On the one hand, DNA and RNA are the most durable physical features of the planet: they have evolved in every detail, but their basic architecture can be inferred to have survived at least 3 billion years of terrestrial history…

Three avenues remain open to us. 1) The reconstruction of plausible emulations of biopoiesis in the laboratory. 2) Observational evidence and palaetiological interpretation of geo- and cosmochemical history of organic molecules: in free space and in condensates such as meteorites and comets. 3) The search for independent evolutions of life beyond narrow terrestrial limits, for an exobiology beyond our own esobiology…

As for exobiology, our principal avenues are 1) telescopic observations from earth, or near orbit, now mainly focused on the substantiation of circumstellar planetary systems like our own; 2) radio-telescopic surveys for possible intelligent signals, and 3) spacecrafted instrumentation visiting the surface of nearby planets, notably Mars.

Joshua Lederberg, Pasteur Centenary Rio February 19-25 ff 1995, I have edited the above remarks but you can read the original in its entirety at the link provided

Term “eobiology” comes from the work of N. W. Pirie, a scientist and philosopher of science — at least, The Living Universe, cited above, attributes “eobiology” to N. W. Pirie, though I was only able to find the term “eobiont” (and not “eobiology”) in Pirie’s work. In any case, with my improved understanding of Lederberg’s formulations of exobiology and related concepts we have the following four concepts that are of particular importance:

● Eobiology: the prefix “eo” means early, so “early biology” or the origins of life

● Esobiology: the prefix “eso” means “inner” or “within” so, in a sense, “our biology,” in other words, terrestrial biology

● Exobiology: the prefix “exo” means “outer” or “outside” so “outer biology” or, if you will, biology in outer space

● Astrobiology: the prefix “astro” means pertaining to the stars, so biology as it pertains to the stars, or biology in a cosmological context

Although I got the original contrast between eobiology and exobiology wrong, I can easily reformulate the distinction I wanted to make in Lederberg’s terms as the contrast between esobiology and exobiology, that is to say, the distinction between terrestrial biology and extraterrestrial biology, which taken together constitute the more comprehensive domain of astrobiology.

I characterized the emergence of astrobiology as being of great importance because it constitutes a fully Copernican science liberated from the prejudices of geocentric biology. My concern was to employ parallel concepts to formulate a similarly fully Copernican Conception of Civilization, and this I see I must now do with the following four concepts:

● Eocivilization the origins of civilization, wherever and whenever it occurs, terrestrial or otherwise

● Esocivilization our terrestrial civilization

● Exocivilization extraterrestrial civilization exclusive of terrestrial civilization

● Astrocivilization the totality of civilization in the universe, terrestrial and extraterrestrial civilization taken together in their cosmological context

Originally I contrasted eocivilization to exocivilization as synthesized in the greater whole of astrocivilization; it is obvious now that the contrast I should have made was that between esocivilization and exocivilization, these two latter of which are unified in astrocivilization.

Although the concepts of esobiology and exobiology can be considered to have been superseded by the concept of astrobiology, the earlier concepts remain useful distinctions within the field of astrobiology, and the same can be said of esocivilization, exocivilization, and astrocivilization: astrocivilization is the comprehensive, Copernican conception of civilization, but it is supplemented by the useful concepts of esocivilization (which for us is terrestrial civilization) and exocivilization (extraterrestrial civilizations), which continue to be valid and useful concepts for the study of civilization.

The original visionary contrast of eobiology and exobiology in Lederberg’s work can be reformulated in the context of civilization as the breadth of civilization from it earliest origins to its far-flung possibilities in the depths of space, which is a sweeping eschatological conception of civilization.

There remains a further subtle distinction that can be made here. Once we understand that the complementary concepts of esocivilization and exocivilization concern the distribution of civilization in space, we recognize that eocivilization is concerned with the distribution of civilization in time. This suggests another concept that would stand opposite that of eocivilization identifying the opposite pole of civilization’s origins — would this be the destiny, aim, or goal of civilization? Such terms are, of course, loaded, and we would be better to avoid them. I discussed in yesterday’s The Industrial-Technological Thesis the tendency of contemporary historians to avoid any mention of “progress,” and for similar reasons we might want to avoid any formulation that suggests a telos of civilization — but this is an interesting question that deserves its own separate discussion rather than a mere aside in passing.

What neutral term could be employed to indicate the opposite of eocivilization, and what term could be employed to indicate the synthesis of eocivilization and its other? The obvious choice would be the prefix “post-” except that I really don’t like the sound of “post-civilization” and what it implies. I think I would prefer some Latinate formulation like Res cultus futurae, but this is awkward contrast to “eocivilization” and “cultus” is a very imperfect translation of “civilization” since ancient Latin had no word for civilization. So I will continue to think about the terminology, but I do want to get the concepts out there while I have them in mind:

● Eocivilization the origins of civilization

● After-civilization that state toward which civilization is evolving, and perhaps also that which comes after civilization

● Metaphysical civilization the totality of civilization in history; the temporal whole of civilization from its earliest origins to its transition into another kind of institution

Thus while I had originally been mistaken in contrasting eocivilization to exocivlization, which I now realize should be the contrast between esocivilization and exocivilization, the term and the concept “eocivilization” turns out to be very useful and highly suggestive.

. . . . .

. . . . .

. . . . .

Species of Civilizations

Friday

---

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.

. . . . .

. . . . .

. . . . .

A Copernican Conception of Civilization

Sunday

---

Elsewhere I have written that the Copernican Revolution still has much unfinished business. For practical men who suppose that the whole of life is dictated by drives and appetites and impulses it might sound like an extraordinary claim to say that the ordinary business of life is contingent less upon one’s responses to stimuli and more upon one’s idea of the world, but just as G.K. Chesterton said that “…for a landlady considering a lodger, it is important to know his income, but still more important to know his philosophy,” I would add that she should also know her tenant’s cosmology. Indeed, philosophies and cosmologies are likely to overlap, and in some cases they coincide.

In Eo-, Exo-, Astro- I wrote about Joshua Lederberg’s distinction between eobiology and exobiology, and how both of these have been absorbed into the more comprehensive science of astrobiology. Astrobiology can be considered an extrapolation and extension of terrestrial biology. This same schema of extrapolation and extension can be readily applied beyond biology to the other life sciences and earth sciences. Ultimately, the result of the systematic extension of our conceptions of science would yield a Copernican conception of science and knowledge in which the earth would no longer be the center, either literally or metaphorically.

A Copernican conception of the sciences, and the production of Copernican knowledge on the basis of a Copernican conception of the sciences, must ultimately move beyond the natural sciences and also embrace the social sciences. I would argue that the social sciences are in more acute need of the Copernican Revolution than the natural sciences, but that it is more difficult to effect a conceptual revolution within the social sciences given their less quantifiable procedures and the inherent ambiguity of observation and evidence in the social sciences. But the fullness of time must inevitably bring us a Copernican political science, a Copernican sociology, a Copernican cultural geography, a Copernican cultural anthropology, and so forth.

Beyond science, we can also seek to extend the Copernican Revolution throughout familiar conceptions of human knowledge that have unwittingly been based on Ptolemaic conceptions of the cosmos. Despite Ptolemaic cosmology now being a scientific museum piece, it continues to influence our thought because its terms and ideas are embedded in our knowledge. Just as we must make an extra effort in order to think in selective terms, according to an evolutionary paradigm — an effort that can be surprisingly difficult because it is so much easier to think in teleological terms, according to a theological paradigm — so too we must make an extra effort to think in non-earth-centered terms, according to a Copernican paradigm, instead of thinking in earth-centered terms, according to a Ptolemaic paradigm. Ultimately, pushing the familiar categories of our thought to the limit, we must formulate a Copernican conception of civilization.

All civilization as we have known it, has been eocivilization; this is terrestrial civilization confined to the surface of the earth. In so far as human beings are a natural product of the earth, and civilization is a natural product of human beings, civilization ought to be the ultimate object of study of a greatly extended conception of the earth sciences. Early in the history of this blog, in Life and Landscape (as well as in subsequent posts, like Art and Landscape), I attempted to show how the ideas by which we live are ultimately grounded in the landscape in which we have made our lives. This is a theme that I have occasionally worked to develop, but the definitive formulation of the idea continues to elude me, even as I continue to pursue it, coming at it from different angles, the better to catch it unaware, as it were. This present formulation here, of civilization as the ultimately object of the earth sciences, is a continuing part of my struggle to precisely delineate the connections between life and landscape.

Civilization as we might imagine it to be off the surface of the earth, either in the form of a greatly expanded human civilization of the future, or in the form of an extraterrestrial civilization not of human origin, would constitute exocivilization. A future science of civilizations would embrace the study both of eocivilization and exocivilization, and in the spirit of scientific objectivity the study of exocivilization ought to be quite indifferent to whether such exocivilization is derived from human civilization or not.

The larger and more comprehensive point of view would be that of astrocivilization, which would comprehend and include both eocivilziation and exocivilziation. The NASA definitions of astrobiology that I quoted in Eo-, Exo-, Astro- can be nicely reformulated (or, if you like, exapted) to express the idea of astrocivilization:

“Astrocivilization is the study of the origin, evolution, distribution, and future of civilization in the universe. This multidisciplinary field encompasses the search for civilized societies in our Solar System and civilized societies outside our Solar System, the search for evidence of the origins and early evolution of civilization on Earth, and studies of the potential for civilization to adapt to challenges on Earth and in space.”

And…

“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.”

I must admit that I rather like the sound of these, and they strike me as an edifying definition of a future science of civilizations.

Problems remain, and there would need to be further revisions of these formulations. We no longer hope to find other civilizations in our own solar system, while at one time this hope was once quite high. Percival Lowell’s poetic vision of a dying Martian civilization building canals to transport remaining water from the poles to the equatorial regions, and H. G. Wells’ darker take on this same vision, making it less poetic and less romantic, but perhaps also more believable, are testimony to the fact that exocivilizations (as well as their motivations and intentions) have been of interest on earth for some time.

More important from a scientific standpoint (since we ought to keep an open mind about other civilizations within our solar system) is the systematic ambiguity between formulating descriptive concepts of civilizations on the one hand, on the other hand and the scientific study of these civilizations. The same ambiguity persists in the term “history,” which can either mean the actual events of the past, or the study of the events of the past. Thus “astrocivilization” could mean the actual civilizations of the universe (which is intuitively quite clear) or the study of such civilizations (which is intuitively not quite as clear, partly because we don’t have an established vocabulary and terminology for the study of eocivilization — except the already-noted ambiguous term “history”).

Much work remains to be done on the study of civilization, just as much work remains to be done in completing the Copernican Revolution.

. . . . .

. . . . .

. . . . .

Eo-, Exo-, Astro-

Monday

---

This post has been superseded by Eo-, Eso-, Exo-, Astro-, which both corrects and extends what I wrote below.

---

The Philosophical Significance of Astrobiology as a

Cosmological Extrapolation of Terrestrial Biology

---

In yesterdays’ Commensurable Perspectives I finished with this observation:

Ecology is the master world-narrative that unifies the sub-narratives employed by individual species in virtue of their perceptual and cognitive architecture. Ultimately, astrobiology would constitute the universal narrative that would unify the ecological narratives of distinct worlds.

The naturalistic narrative has the power to unify even across species and across worlds. This power may not be particularly evident at present, but in the long term future of our species (if our species does in fact have a long term future) this power will prove to be crucial.

If indeed astrobiology is the universal narrative of life, that gives astrobiology a privileged position among the sciences. That is a tall order. But what is astrobiology? At one time I had heard both the terms “exobiology” and “astrobiology” and I was not quite clear about the exact difference between the two, or how each was defined. Thereby hangs a tale. The distinction between the two is in fact a very interesting story, and it is a story to which an entire book has been devoted, The Living Universe: NASA and the Development of Astrobiology, by Steven J. Dick and James E. Strick.

I urge the reader to get this book and peruse it for yourself for the detailed version of the emergence of astrobiology as a scientific discipline. I will give only the bare bones of that story here, which will be only enough to grasp the crucial concepts involved. And our interest is in the concepts, not the personalities.

Joshua Lederberg before he had formulated the distinction between eobiology and exobiology.

Exobiology is the older term, introduced by Joshua Lederberg (first used in a public lecture in 1960), and contrasted by him to eobiology. Exobiology has some currency in the public mind, but I didn’t know about eobiology until I read about the history of the discipline. However, the contrast between the two terms is conceptually important. Exobiology is concerned with biology off the surface of the earth, while eobiology is biology on the surface of the earth. (cf. p. 29) In other words, all biological science prior to human spaceflight was eobiology, even if we didn’t know that it was eobiology. Another way to formulate this distinction is to say that eobiology is the biology of the terrestrial biosphere, while exobiology is the biology of everything else.

In the book The Living Universe: NASA and the Development of Astrobiology the authors give a lot of background on the internal politics and budgeting of NASA and how this affected the emergence of astrobiology. It is an interesting story, but I will not go into it here, as our interest at present is exclusively with the conceptual infrastructure of the discipline. Suffice it to say that in 1996 the first attempts were made to define astrobiology (cf. p. 202), and within a couple of years there was a virtual Astrobiology Institute.

The NASA astrobiology website characterizes astrobiology as follows:

“Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe. This multidisciplinary field encompasses the search for habitable environments in our Solar System and habitable planets outside our Solar System, the search for evidence of prebiotic chemistry and life on Mars and other bodies in our Solar System, laboratory and field research into the origins and early evolution of life on Earth, and studies of the potential for life to adapt to challenges on Earth and in space.”

The NASA strategic plan of 1996 gives this definition of astrobiology:

“The study of the living universe. This field provides a scientific foundation for a multidisciplinary study of (1) the origin and distribution of life in the universe, (2) an understanding of the role of gravity in living systems, and (3) the study of the Earth’s atmospheres and ecosystems.”

The important lesson to take away from this is that astrobiology is the more comprehensive concept, and that in fact we can consider astrobiology the union of eobiology and exobiology. This sounds simple enough (and it is), but it is important to understand the conceptual leap that has been taken here.

From the perspective of astrobiology, earth sciences are only fragments of far larger and more comprehensive sciences. Just as all biology was once eobiology, the same observation can be made in regard to the other earth sciences, and the same tripartite conceptual distinction can be brought to the other earth sciences. We can formulate eogeology and exogeology unified in astrogeology; we can formulate eohydrology and exohydrology unified in astrohydrology; we can formulate eovulcanology and exovulcanology unified in astrovulcanology; we can formulate eoclimatology and exoclimatology unified in astroclimatology. All of these are cosmological extrapolations of earth sciences. One suspects that, in the future, the prefixes will be dropped and we will return to climatology simpliciter, e.g., but while the conceptual revolution is underway it is important to retain the prefixes as a reminder that science is no longer defined by the boundaries of the earth.

I assert that this is a conceptual leap of the first importance because what we have with astrobiology is the formulation of the first truly Copernican science; astrobiology includes eobiology but it is not exhausted by eobiology; it is supplemented by exobiology. The earth, for obvious reasons, remains important to us, but it no longer dictates the center of our science. All mature sciences will eventually need to take this Copernican turn and dethrone the earth from the center of its concern.

We can take a further step beyond this conceptual formulation of Copernican sciences by observing that traditional earth sciences began as local enterprises, and it has only been in recent decades that truly global sciences have emerged. These global sciences have culminated in objects of scientific study that take the world entire as their object. Thus biology has converged upon study of the biosphere; hydrology has converged on study of the hydrosphere; glaciology has culminated in the study of the cryosphere. Copernican sciences based on the model of astrobiology can go one better than this, transcending earth-defined “-spheres” in favor of more comprehensive concepts.

When I spoke last year on “The Moral Imperative of Human Spaceflight” at the NASA/DARPA 100 Year Starship Study symposium it was my intention to spend some time on the emergence of Copernican sciences, but I didn’t have enough time to elaborate. I cut most of that material out and still was rushed. The point that I wanted to make there was that the concepts of the biosphere, the lithosphere, the geosphere, hydrosphere, cryosphere, atmosphere, anthrosphere, sociosphere, noösphere, and technosphere are essentially Ptolemaic concepts. (If the proceedings of the symposium are published, and if my paper is included, this contains my first sketch of Copernican sciences as transcending these earth-defined “-spheres.”) The Copernican Revolution entails the formulation of Copernican concepts to supersede Ptolemaic concepts, and this work is as yet unfinished. In some spheres of human thought, it has scarcely begun.

One way to transcend our Ptolemaic concepts and to replace them with Copernican concepts, and thus to extend the ongoing shift to a truly Copernican perspective, is to substitute for the earth-defined “-spheres” a conception of the object of the sciences not dependent upon the earth, and this can be done by defining, respectfully, biospace (in place of the biosphere), lithospace, geospace, hydrospace, cryospace, atmospace, anthrospace, sociospace, noöspace, and technospace. In so far as we can facilitate the emergence of Copernican sciences, we can contribute to the ongoing Copernican Revolution, which will someday culminate in a Copernican civilization (if we do not first destroy ourselves).

We can pass beyond the earth sciences and the natural sciences and similarly extend our conceptions of a the social and political sciences. Although concepts from the social sciences are not usually expressed in geocentric terms — except for the above-mentioned anthrosphere, sociosphere, noösphere, and technosphere (which are not employed very often) — our social and political thought is usually even more tied to planetary prejudices than the concepts of the natural sciences. Thus we can extend our conception of politics by distinguishing between eopolitics and exopolitics, both of which are subsumed under astropolitics. Similarly, we can formulate eoeconomics and exoeconomics, subsumed by astroeconomics, eostrategy and exostrategy, subsumed by astrostrategy, and so forth.

As a final note, it is ironic that the breakthrough to a Copernican science should occur first with biology, because biology was among the latest of the sciences to actually attain a scientific status. Prior to Darwin, biological theories were essentially theological theories with but a few exceptions. Darwin put biology on a firm biological footing and created the discipline in its modern scientific form. Thus biology was among the last of the sciences to attain a modern scientific form, though it was the first to attain to a Copernican form.

. . . . .

This post has been superseded by Eo-, Eso-, Exo-, Astro-.
.

. . . . .

. . . . .

. . . . .

Commensurable Perspectives

Sunday

---

There is an ancient parable from India about several blind men who encounter an elephant. The story is well known in many different versions, in all of which the blind men disagree as the nature of the animal — one touches its leg and says that an elephant is like a tree; another touches its ear and says that an elephant is like a fan; another touches its trunk and says an elephant is like a snake, and so forth.

We know that the elephant is one and whole, but the blind men of the parable do not know the elephant as a single reality; they are blind in more than one sense.

The same problem — the problem of appearance and reality — has been central to Western metaphysics since the beginning of philosophy to the present day. I have previously written about the philosophical antipathy and rivalry between Henri Bergson and Bertrand Russell in the early part of the twentieth century (in Epistemic Space: Mapping Time). Both of these antagonistic figures treated the same problem. Here is Bergson’s version:

There is in this something very like what an artist passing through Paris does when he makes, for example, a sketch of a tower of Notre Dame. The tower is inseparably united to the building, which is itself no less inseparably united to the ground, to its surroundings, to the whole of Paris, and so on. It is first necessary to detach it from all these; only one aspect of the whole is noted, that formed by the tower of Notre Dame. Moreover, the special form of this tower is due to the grouping of the stones of which it is composed; but the artist does not concern himself with these stones, he notes only the silhouette of the tower. For the real and internal organization of the thing he substitutes, then, an external and schematic representation. So that, on the whole, his sketch corresponds to an observation of the object from a certain point of view and to the choice of a certain means of representation.

Now beneath all the sketches he has made at Paris the visitor will probably, by way of memento, write the word “Paris.” And as he has really seen Paris, he will be able, with the help of the original intuition he had of the whole, to place his sketches therein, and so join them up together. But there is no way of performing the inverse operation; it is impossible, even with an infinite number of accurate sketches, and even with the word “Paris” which indicates that they must be combined together, to get back to an intuition that one has never bad, and to give oneself an impression of what Paris is like if one has never seen it.

Henri Bergson, An Introduction to Metaphysics

And here is Russell’s version (which I previously quoted in Appearance and Reality in Cosmology):

With the naked eye one can see the grain, but otherwise the table looks smooth and even. If we looked at it through a microscope, we should see roughnesses and hills and valleys, and all sorts of differences that are imperceptible to the naked eye. Which of these is the ‘real’ table? We are naturally tempted to say that what we see through the microscope is more real, but that in turn would be changed by a still more powerful microscope. If, then, we cannot trust what we see with the naked eye, why should we trust what we see through a microscope? Thus, again, the confidence in our senses with which we began deserts us.

. . .

Similar difficulties arise when we consider the sense of touch. It is true that the table always gives us a sensation of hardness, and we feel that it resists pressure. But the sensation we obtain depends upon how hard we press the table and also upon what part of the body we press with; thus the various sensations due to various pressures or various parts of the body cannot be supposed to reveal directly any definite property of the table, but at most to be signs of some property which perhaps causes all the sensations, but is not actually apparent in any of them. And the same applies still more obviously to the sounds which can be elicited by rapping the table.

Thus it becomes evident that the real table, if there is one, is not the same as what we immediately experience by sight or touch or hearing. The real table, if there is one, is not immediately known to us at all, but must be an inference from what is immediately known. Hence, two very difficult questions at once arise; namely, (1) Is there a real table at all? (2) If so, what sort of object can it be?

Bertrand Russell, The Problems of Philosophy, Chapter 1

Bergson later goes on to add, after his exposition of the problem:

“Both empiricists and rationalists are victims of the same fallacy. Both of them mistake partial notations for real parts, thus confusing the point of view of analysis and of intuition, of science and of metaphysics.”

It is almost as though Bergson realized that his own “empiricism” (after a fashion) might be contrasted with Russell’s “rationalism.” This is where the problem of appearance and reality meets the problem of the one and the many. Reality is one; appearance is many. How are we to understand how the one presents itself as many, and how the many are unified in the one?

There are times when the many perspectives on one and the same world seem unproblematic. The case of the blind men and the elephant can be resolved by bringing the blind men back to the elephant and directing them to feel the continuity of the various parts of the elephant with each other. And when many different scientific experiments confirm one and the same theory by testing different aspects of that theory in different ways, but all independently (and reproducibly) confirm one and the same theory, we know that we have one scientific theory that despite its many predictions concerns itself with one and the same world.

There are other times when the unity of the world and of the diverse perspectives upon the world are more problematic. Everyone, I think, is well familiar with the problems posed by competing and incommensurable narratives of what is believed to be the same sequence of events. This difficulty is encapsulated in the pop-culture dichotomy of, “he said/she said,” where the incommensurability is the incommensurability of gendered perspective.

I have elsewhere cited Thomas Nagel’s famous paper, “What is it like to be a bat?” (in Addendum on the Origins of Time) and noted that Nagel chose the example of a bat because, as a vertebrate and a mammal it is not all that different from primates (and presumably has experiences of the world not unlike those that primates have of the world), but the bat primarily experiences the world through sonar rather than through sight. That makes the bat very different from a primate, and presumably results in a dramatically different experience of the world — hence, there is something that it is like to be a bat, and this “something” is significantly different from what it is like to be a primate.

There are many ways of seeing the world, and some of these ways do not even involve “seeing.”

There is a sense in which organisms that relate to the world through fundamentally different sensory mechanisms experience a different world. The bat’s world constructed from sonar, the pit viper’s world constructed from infrared-sensing pits, the shark’s world constructed from electroreceptors, and the primate’s world of stereoscopic color vision are, in a sense, different “worlds.” But only “in a sense,” because in another sense these diverse senses reveal the same world, as is apparent when these different organisms with their distinct sensory mechanisms interact — sometimes recognizing each other (which I attempted to describe in The Eye of the Other), sometimes just avoiding each other, while at other times preying on each other or fleeing from predation.

Biodiversity means perceptual and epistemic diversity.

If we can find a way to put these different perceptions of the world together, we will have a much more comprehensive account of the world that that based on the observations of a single species. That is to say, the perspectives of other species, if only we could tap into them, would provide countervailing evidence to lessen our anthropic bias. We can think of these other perspectives as narratives, with each narrative of the world being ontologically derived from the structure of the organism, which involves both its sensory organs and its functional relationship to its environment.

If we take a naturalistic perspective and assume that the natural world is, unproblematically, as it presents itself to be, with a variety of many distinct species involved in relationships of cooperation and competition, we know that these radically distinct perspectives on the single natural world that hosts us all are in fact fully commensurable. Although no one individual, and no one species, has the synoptic perspective that includes all radically distinct forms of sensory perception, the distinct perspectives have a unity in the unity of nature.

Naturalism, then, implies the commensurability of radically distinct world-narratives that are ecologically integrated even if we cannot understand this integration or experience the world from any perspective other than that common to our species.

That the perspectives of distinct species possess a de facto commensurability despite their profound differences puts the supposedly incommensurable theoretical views of human beings into perspective. It is, of course, the position of Thomas Kuhn’s philosophy of science that different theoretical models of the world constitute distinct paradigms, and that these paradigms are incommensurable.

The “theories” implicit in the sensory apparatus of any two distinct species are far greater than the difference between any two theories maintained by the same species, though we must entertain the possibility that our ideas give us a dimension of differentiation that does not exist for all species, just as not all species possess sensory organs (as, for example, with micro-organisms), so that the possession of sensory organs also involves a dimension of differentiation from species lacking sensory organs.

The primate brain devotes much of its capacity to the heavy processing demands of stereoscopic color vision. The mollusk brain also processes fairly sophisticated visual stimuli, but it also devotes a significant amount of its capacity to the control of the cells on the surface of its skin, which allows octopi and cuttlefish to produce both brilliant displays and effective camouflage on demand. Given brains structured around these very different cognitive demands, I imagine that primates think and view the world very differently from the way that mollusks think and view the world — though these differences do not prevent the species from interacting, though primates and mollusks don’t interact all that much because of their distinct ecological niches.

If species possessing a cognitive architecture as profoundly different as that represented by primates and mollusks can achieve a de facto commensurability through their common participation in a single biosphere, then the incommensurability of different human points of view does not seem all that bleak.

Ecology is the master world-narrative that unifies that sub-narratives employed by individual species in virtue of their perceptual and cognitive architecture. Ultimately, astrobiology would constitute the universal narrative that would unify the ecological narratives of distinct worlds.

The naturalistic narrative has the power to unify even across species and across worlds. This power may not be particularly evident at present, but in the long term future of our species (if our species does in fact have a long term future) this power will prove to be crucial.

. . . . .

. . . . .

. . . . .

Addendum on the Fermi Paradox

Saturday

---

A few days ago in Why the Fermi paradox must be taken seriously I attempted to demonstrate that the technology of any peer civilizations extant in the Milky Way would have singled out the earth as an interesting place to visit and thus would likely have made us the target of alien exploration if advanced peer civilizations existed in the Milky Way.

I neglected to mention that, to a certain extent, this applies even to nearby galaxies, although the farther away the galaxy we reference, the more difficult it would be to obtain the scientific knowledge of the earth at a distance, and the more difficult it would be to travel. But difficulty is not impossibility, and if we contemplate the possibility of very old peer civilizations in the universe, their technology would be so advanced that the difficulties would be reduced.

It is one of my dissatisfactions with most books on astrobiology, exobiology, SETI, and space travel that they implicitly confine their scope to the Milky Way galaxy without explicitly acknowledging this restriction. Of course, the Milky Way galaxy is a very big place, but in the several posts in which I have referenced the Hubble Ultra Deep Field Image (which has been called “the most important image you will ever see”), when we consider the universe on a very large scale, galaxies fill the sky like the familiar stars filling our night sky. The Milky Way is a very big place, but the universe is a much bigger place, and we must understand the Milky Way in the context of the universe.

The nearest large galaxy to us (excepting the Magellanic Clouds) is the Andromeda Galaxy, which is an elegant spiral galaxy larger than the Milky Way. In the fullness of time, the Andromeda spiral galaxy and the Milky way galaxy will collide, the supermassive black holes at the center of each galaxy will eventually merge, and a new and even larger galaxy will be born from the collision. But that will be a very long time from now.

In the meantime, the Andromeda galaxy is about two and half million light years from us. That means that any observation of the earth from Andromeda would be two and a half million years old. While this is a long time ago for us, in geologic terms it is not all that long ago. While a peer civilization in the Milky Way would experience a lookback time of not more than 100,000 years, bringing observations to the time of the emergence of homo sapiens, the lookback time from the Andromeda galaxy would bring the observer back to a time when several hominid species were ranging around Africa. This corresponds roughly to the time of the emergence of homo habilis and the beginning of tool use among hominids. While this time scale means a lot to us, the biosphere then and now is almost identical, and to an advanced peer civilization then and now on the earth would look pretty much the same. The earth would still be positively brimming with life and therefore a very interesting place to visit.

Assuming only advanced technology and no exceptions to the laws of physics, a starship launched from the Andromeda galaxy would take at least two and a half million years to arrive, but due to time dilation at relativistic velocities, hardy explorers could make the trip in a single lifetime. Somewhere I read (I can’t recall exactly where) that a starship accelerating at the relatively modest rate of 32 feet per second (which has the added value of providing artificial gravity onboard) would only experience about 24 years of elapsed time on the ship during a voyage between Andromeda and the Milky Way. If we were to combine this sort of feasible travel technology with induced hibernation, it is entirely plausible that a group of explorers could travel between galaxies. And the closer one approximates the speed of light, the greater the time dilation, so for explorers there would be a strong incentive to “push the envelope” as it were.

Again, this involves some very advanced engineering, but it doesn’t violate any known laws of physics, and the technology involved is at least comprehensible to us, even if we aren’t in a position to build it ourselves any time soon.

Now, you might ask why anyone would leave behind their world by two and a half million years in order to go to another galaxy. In the books I have been reading lately I have found that several authors are remarkably sanguine about this, and confidently predict that robotic exploration would be so much more preferable to actual exploration by conscious agents that the latter possibly is simply set aside. For example, I have found this more or less to be the implicit viewpoint of Timothy Ferris in Coming of Age in the Milky Way, of Michio Kaku in The Physics of the Future, and of Paul Davies in The Eerie Silence.

I don’t buy this at all. Just as there are, in our contemporary civilization, many people who enjoy the comforts of home, there are always a few people who climb mountains. And, similarly, when the technology is available, many people will continue to enjoy the comforts of home, but there will always be those who are so driven by the need to explore that they will leave behind home and family and indeed the entire world that they know in order see to what lies beyond the horizon. It is perfectly reasonable to me that a group of explorers might choose to leave behind the Andromeda galaxy merely for the purpose of investigating an interesting planet in the Milky Way. In fact, I might choose to do this myself, were it a viable option.

As we consider galaxies and possible peer civilizations at a further reach, beyond the local group and the local cluster of galaxies, the possibilities of relativistic time dilation continue to make exploration possible on an inter-galactic scale, but it would become much more difficult to find interesting planets at this distance, even with techniques like gravitational lensing. However, as we have seen, difficulty is not the same thing as impossibility.

However, another factor comes into play as we move further away from the Milky Way. While those on board a very fast intergalactic starship (approximating while never achieving the speed of light) would experience very little time, time outside this starship would elapse at the accustomed rate, and that means that the more distant the galaxy, the longer ago in time a ship would have to have been launched.

The problem with this, and the problem with much SETI research, is a failure to engage with the anthropic cosmological principle, which seems to be concerned with human existence, but is equally valid (in its valid forms, that is) for any organic conscious agents that emerge according to the laws of nature and natural selection. The farther away we consider, the further back we go in time, and the further back we go in time, the less the universe has evolved toward its present state. At much earlier states of cosmic evolution the elements requisite for peer life, and most especially for peer industrial-technological civilizations, simply do not exist.

A solar system that could support peer industrial-technological civilization would have to have formed after the heavier elements had been formed inside stars from earlier stellar populations, since the only way you can get elements like iron and uranium from an initial stage of hydrogen is, over the course of galactic evolution, for these elements to be cooked up inside successive generations to stars, and then ejected into the universe by way of supernovas. These elements then go on to form solar systems that include the kind of metals that are required for industrial-technological civilization. This takes many generations of stars. As a result, if you have far enough back in time, you arrive at a time before these generations of stars have elapsed, and therefore the conditions for peer civilizations do not exist.

There is a cosmological window in the natural history of the universe for industrial-technological civilizations to emerge. We cannot yet state with any precision how long this window persists, or when it starts. Almost certainly there could be peer civilizations a million or more years old in the universe, but somewhere there is a limit older than which a civilization in our universe could not be. Thus when SETI researchers confidently speak of civilizations millions years old, I am immediately skeptical. It is not impossible, but the further back in time you go, the less possible it becomes.

It is worthwhile to think about this in more detail, as it also has consequences for the Fermi paradox. If we regard it as a mere matter of chance when an industrial-technological civilization emerges from its organic origins — which, it seems to me, is something we must acknowledge in the spirit of methodological naturalism — then it is just as likely that our civilization just happens to be to first such to emerge in the Milky Way, on perhaps even in the local group of galaxies, as it is that we are not the first. Of course, this is not a function or mere chance — it is chance constrained by the anthropic cosmological principle, as well as chance constrained by natural selection. But this is only a rough formulation. An adequate formulation would take more time and more thought.

. . . . .

. . . . .

. . . . .

SETI as a Process of Elimination

Monday

---

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.

. . . . .

. . . . .

. . . . .