I. Aliens on Earth
A few months back I was pleased to see a description in print of an idea that’s been kicking around in my brain for a while now: if the earth is so old, why couldn’t there have been other intelligent species before us who have simply gone extinct, vanished without a trace, their fossils erased by the epochal movement of the continents? I mentioned this to a friend over beer and he raised the objection that some trace of these creatures would surely have remained for us to find; look at the extent to which we’ve transformed our environment in ways that won’t disappear for an extremely long time. But this strikes me as unconvincing. Such changes as we’ve inflicted—even if we go all the way back to the pyramids—are extremely recent; for the vast majority of human history, and in the vast majority of human societies, there was little that would have lasted. Prehistoric humans left very little evidence of their existence beyond some stone tools and fossils, and it’s easy to imagine such things being ground up and digested by the tectonic processes of millions of years. Or simply lost, transported to locations—under the sea, beneath layers of earth and stone, on mountains where archeological digs are impractical—where we have yet to discover them, and may never do so. And all this presumes that “intelligence” must necessarily resemble in other species what it looks like in humans, manifested in the forms that we’ve tended to valorize: tool-making, technological development, the manipulation of the external environment. Why couldn’t intelligence take other forms, address other needs? Why couldn’t it, for example, be addressed more to the development of social relationships, or the inner life, internal insight? The objection occurs to me here that there ought to be some plausible reason why such an intelligence would evolve. What would be the selective pressures that would drive it? But that, too, seems answerable, at least in the case of social intelligence. Whether it’s social cooperation for some external purpose (hunting, gathering), or internal competition for reproduction, there are plausible mechanisms that could provide the impetus. On the one hand, we can point to existing examples of such development (orcas, wolves, chimpanzees, etc.); on the other, one could easily object that these examples demonstrate the weakness of the proposal, since these species have not developed intelligence of the kind we tend to think of in this context. But we should not forget that our existence itself may have precluded development in some other line. In the absence of competition from a species like ourselves, perhaps the wolves or orcas would have gone on to develop a level of intelligence that we’d recognize as comparable to our own, if different in kind. And this of course assumes we’d be able to recognize it as such. Once we acknowledge that point even murkier questions arise. For one thing, there are the social insects, in whom intelligence is supra-organic. Bacteria and trees also exhibit aspects of what we call intelligence but in forms so different from our own experience (macroscopic, centered on individual organisms that are both mobile and relatively discrete) as to make recognition difficult. And what about intelligence that relies on inter-species networks for its complexity and information-processing capacity—what we might call symbiotic intelligence? Again, I’m thinking about trees and their relationship with fungi, other plants, etc. Come to think of it, though, our own intelligence is symbiotic in this way, with its interdependence with gut bacteria (not to mention the mitochondrial integration we share with most eukaryotes). Finally, I find myself wondering about the role of contingency in this whole business: what fortuitous combination of factors pushed our mental evolution into runaway, so that our brains and their various externalizations, both material and social, hypertrophied to the extent that I can sit here on my back porch, high on caffeine, typing away on my laptop for the sheer pleasure of speculating about all this? In our case it may have involved the selective advantage conferred by the synergy of toolmaking, language, social organization, bipedalism, and maybe sweating. Or something like that; the theories have changed more than once during my lifetime and will likely change again, but the basic point remains that the precise combination, whatever it was, happened fortuitously. One can imagine, then, some equally fortuitous yet different combination of factors that would favor an intelligence not given to paving large surfaces or piling rocks on top of each other or making extremely long-lasting garbage out of hydrocarbons, such that we’d be hard-pressed to find any evidence of its existence after millions of years. It’s that geologic timescale that I began with, and that I want to end this speculation with: the idea that the span of time that we are talking about is so vast it beggars the imagination, and that far more is possible than we have tended to suppose.
II. Aliens in space
Speaking of which… If our ideas about intelligence are parochial, in the sense that we tend too easily to assume that all intelligence must look like ours, so too, perhaps, are our ideas about life itself. Perhaps “life” as we think of it is just one possibility among many, in the same way that the kinds of life we once supposed were everything—plants and animals, basically; the things we can see with the naked eye—have had to make room for forms of life hitherto unimaginable, whether simply because they were too small to see (from plankton to viruses, the revolution in our understanding introduced by the invention of the microscope) or because they happen in places completely inaccessible (hydrothermal vents), and which challenge our basic understanding of what constitutes a living thing.
I’ve been thinking about this off and on for decades; years ago it took the form of wondering whether clouds could constitute a kind of “life.” (For “life” in quotation marks substitute the entirely speculative notion of some supra-category that subsumes life along with other hypothetical instances, members of the same set yet different from what we call life.) I mean both earthly clouds of water vapor and whatnot, and interstellar clouds of gas and dust. Now I find myself wondering about life in (not on) the sun, life that comprises parts of the sun itself rather than some discrete organism, some physical entity subsisting on it. Could enormous convection currents give rise to stable, self-organizing and self-replicating structures like crystals? Could such structures achieve sentience of some kind? “Sentience” here meaning some sort of stable pattern complex enough to store and detect information, complex enough even to achieve some kind of self-recognition. I’m using the term “information” in the Batesonian sense of “a difference that makes a difference.”
I was provoked to write all this down when reading David Wootton’s The Invention of Science, where he’s discussing Giordano Bruno’s ideas about an infinite universe where space (and time?) are relative, the sun is just one star among many, the earth and other planets shine by reflected light, and life on other planets and stars is entirely possible. “Since Bruno did not believe that Christ was the saviour of mankind (he was a sort of pantheist),” Wootton explains, “he did not have to worry about how the Christian drama of sin and salvation was played out in this infinity of worlds” (147). He was also one of the early adopters of the Copernican theory that the earth revolves around the sun. Bruno was ultimately imprisoned in solitary confinement, tortured, and burned at the stake for his ideas. “He had refused to recant his heresies, including his belief in other inhabited worlds” (Wootton 149). Especially relevant to these speculations, Wootton says that according to Bruno “even the sun and the stars might be inhabited, for they could not be equally hot all over, and there might be creatures, quite different from ourselves, who thrive on heat.”
The discussion of Bruno inevitably reminds me of Calvino’s references to the Renaissance thinker in Six Memos for the Next Millennium, and I was surprised and delighted to find, when I went looking for them, a discussion of crystals and flames as opposing yet complementary metaphors for thinking about the organization of life (and literature). The entire passage is too long to quote here, but I can’t resist sharing a bit. After invoking Bruno and others on the subject of the infinite, Calvino writes,
The crystal, with its precise faceting and its ability to refract light, is the model of perfection that I have always cherished as an emblem, and this predilection has become even more meaningful since we have learned that certain properties of the birth and growth of crystals resemble those of the most rudimentary biological creatures, forming a kind of bridge between the mineral world and living matter (70).
I’m not sure, but I think he’s thinking here of the notion that life may have begun with evolving crystals of clay.
He then quotes Massimo Piattelli-Palmarini on the contrasting image of crystals and flames: “the models for the process of formation of living beings ‘are best visualized by the crystal on one side (invariance of specific structures) and the flame on the other (constancy of external forms in spite of relentless internal agitation)’” (70).
The contrasting images of crystals and flames as models for thinking about the self-organizing property of life (or “life”) come together in this vision of life in the sun, where massive currents of energy—like the unimaginable scale of geologic time, far beyond our capacity to conceive—give rise to stable yet ever-shifting structures that have the capacity to achieve something like sentience.