Wednesday, August 02, 2017

The SETI Coat of Arms

Somewhere along the line of my career I started to think, "Okay, maybe I won't find the signal (I can do the best job I can [but] I really can't control that). But if I can leave this field financially stronger than when we started—if we can find a way, by the time that I'm finished cheer leading, to have a stable financial funding for this kind of exploration—which may, indeed, be multigenerational—then I will have done something pretty damned good. And I can feel very good about that." (Jill Tarter)

This remark during last month's SETI Talk about Sarah Scoles' biography of Jill Tarter reminded me of a short story by Franz Kafka called "The City Coat of Arms". It is, of course, well worth reading in its own right and it is only about 500 words long so you might want to go ahead and find it and read it before reading the rest of this post. I don't want to spoil your enjoyment.

The story is about the building of the Tower of Babel. In fact, it's not so much a story as a page from a fictional history book. After noting that the building arrangements were "perhaps too perfect", our historian establishes the central premise:

The essential thing in the whole business is the idea of building a tower that will reach to heaven. In comparison with that idea everything else is secondary. The idea, once seized in its magnitude, can never vanish again; so long as there are men on the earth there will be also the irresistible desire to complete the building.

Anyone familiar with the rhetoric of SETI will see the connection. As Carl Sagan put it in his famous essay, "The Quest for Extraterrestrial Intelligence" (which, incidentally, uses a Kafka quote about the silence of the Sirens as its epigraph),

The search for extraterrestrial intelligence is the search for a generally acceptable cosmic context for the human species. In the deepest sense, the search for extraterrestrial intelligence is a search for ourselves. [...] It is difficult to think of another enterprise ... that holds as much promise for the future of humanity.

But Kafka understood, as Tarter also has come to understand, that once the, let's say, infinite promise of the project has taken hold of the imagination it does not need to succeed in any foreseeable future in order to retain its relevance, or, as Tarter rightly notes, its funding. Indeed, its significance for humanity will come from the silence, not the song, of sirens. Like Tarter, Kafka also seizes on the multi-generational aspect:

[O]ne need have no anxiety about the future; on the contrary, human knowledge is increasing, the art of building has made progress and will make further progress, a piece of work which takes us a year may perhaps be done in half the time in another hundred years, and better done, too, more enduringly. So why exert oneself to the extreme limit of one's present powers? There would be some sense in doing that only if it were likely that the tower could be completed in one generation. But that is beyond all hope.

Here, some SETI enthusiasts will say that the analogy breaks down. It is not they will insist "beyond all hope" that SETI will succeed in a generation. Yuri Milner has committed $100 million dollars to a ten-year push to find whatever there is to find—the Breakthrough Listen project. But I would encourage them to read a recent paper by Claudio Grimaldi. He shows quite convincingly that the probability of detecting a signal, even if the galaxy is teeming with intelligent life (Sagan estimated a million civilizations capable of radio astronomy) is exceedingly small. This is because the signals themselves, by definition transmitted on a "historical" timeframe, disappear in the astronomical volume of the galaxy. They simply can't fill in any reasonable volume of galactic space to make it very likely that the earth's orbit will pass through the decidedly finite volume occupied by the signal.

It is only if the alien civilization had in fact undertaken to build a lighthouse to reach the heavens, to signal continuously in all directions for millions and millions of years, that their signal would have any chance of reaching us at our particular moment in history, i.e., the ten-year funding framework of the Breakthrough Listen project. So Tarter is right, something more permanent needs to be established. But here, too, Kafka must be heard:

It is far more likely that the next generation with their perfected knowledge will find the work of their predecessors bad, and tear down what has been built so as to begin anew.

Again, there are echoes of the SETI rhetoric. We need to "speed up the search," as Shostak puts it. We need more powerful computers "on the back end" to analyze the data. We might not even know, yet, what to look for. The aliens might be messaging to us using, not radio waves, but laser beams or neutrino streams. We just don't know! On the one hand, this cornucopia of possibilities gives us hope. On the other hand, the hope is distributed across a probability space that requires millions of years (of listening and of sending) to achieve reasonable "coverage" (to use Grimaldi's term). "Such thoughts paralyzed people's powers," Kafka says of the builders of Babel,

and so they troubled less about the tower than the construction of a city for the workmen. Every nationality wanted the finest quarters for itself, and this gave rise to disputes, which developed into bloody conflicts. These conflicts never came to an end; to the leaders they were a new proof that, in the absence of the necessary unity, the building of the tower must be done very slowly, or indeed preferably postponed until universal peace was declared.

This is where it gets real for me. It is important to remember that SETI is not just a scientific field but a political situation. It must lobby for resources, as Tarter rightly points out, and it must manage its own internal conflicts and intrigues. Sarah Scoles, it should be remembered, has written not just about Jill Tarter but also about Geoff Marcy. She is not just interested in the former's heroic quest but that latter's infamous transgressions. She has, as it were, one auspicious and one drooping eye on astronomy. She is interested in the struggle for both truth and justice. She covers both the scientific discoveries and the political conflict.

"The time," says Kafka,

was spent not only in conflict; the town was embellished in the intervals, and this unfortunately enough evoked fresh envy and fresh conflict. In this fashion the age of the first generation went past, but none of the succeeding ones showed any difference; except that technical skill increased and with it occasion for conflict.

But, throughout it all, surely there is Sagan's "enterprise"—that great hope for humanity—animating these scientific and political projects? Well, one sometimes wonders. As Kafka puts it:

[T]he second or third generation had already recognized the senselessness of building a heaven-reaching tower; but by that time everybody was too deeply involved to leave the city.

It's this deep involvement that I discern in Tarter's remark, which she specifically frames in terms of her "legacy". It is no longer important to discover a signal. Indeed, Grimaldi may be right and the entire enterprise may be senseless. (I have my own back of the envelope calculation that suggests something similar.) What is important is to embellish "the city", to leave the field "financially stronger", as Tarter puts it, than we found it.

Remember that it may take generations. Tarter is still part of the first generation—those who came up with the idea of finding an intelligent signal and might yet die trying. There will now be a second and third generation, whose efforts may also fail, but will involve a great deal effort to justify increasing investments in time and technology. The odds for them will not improve markedly. In order to beat Grimaldi's house you need to listen for millions of years for signal that has been transmitted for just as long. Kafka anticipates the cultural impact of despair on such an astronomical scale:

All the legends and songs that came to birth in that city are filled with longing for a prophesied day when the city would be destroyed by five successive blows from a gigantic fist. It is for that reason too that the city has a closed fist on its coat of arms.

Or, in our case, all the movies are filled with gigantic asteroids that threaten humanity with extinction. Less dramatically, the SETI Institute's logo depicts, not so much a signal, as a question. Perhaps it should consider a fist with the tail of a comet?

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