As my readers will know, over the past few years I have been engaged in a critique of the long-standing rationale for the search for extraterrestrial intelligence (SETI). The foundation for this rationale is the so-called Drake “equation,” which is a tool for speculating about the possibility of ETI – emphasis on speculating. (See my blog post of December 10, 2009.)
Now Nathalie Cabrol, an astrobiologist and director of the SETI Institute’s Carl Sagan Center for the Study of Life in the Universe*, has published a manifesto of sorts, in the journal Astrobiology, calling for an updated rationale and new “roadmap” for SETI.
Here’s Cabrol’s abstract (the paper is “open-access” at the journal’s web site until July 26): “Advances in planetary and space sciences, astrobiology, and life and cognitive sciences, combined with developments in communication theory, bioneural computing, machine learning, and big data analysis, create new opportunities to explore the probabilistic nature of alien life. Brought together in a multidisciplinary approach, they have the potential to support an integrated and expanded Search for Extraterrestrial Intelligence (SETI), a search that includes looking for life as we do not know it. This approach will augment the odds of detecting a signal by broadening our understanding of the evolutionary and systemic components in the search for extraterrestrial intelligence (ETI), provide more targets for radio and optical SETI, and identify new ways of decoding and coding messages using universal markers.”
Still sounds like SETI to me… (see my blog post of July 16, 2015).
In my paper “Astrobiology in culture: the search for extraterrestrial life as ‘science’,” also published in Astrobiology (12(10), 2012), I examined the social construction of authority, credibility, and legitimacy for astrobiology and, in comparison, SETI. I concluded that “in the current cultural environment, non-experts might be led to conclude that the ultimate goal of astrobiology is to make contact with extraterrestrial intelligent life. For self-described astrobiologists working on SETI, it may be, but for the astrobiology community writ large, it is not.” I also noted in this paper that “one aspect of the study of the origin and evolution of life in the universe that scientists do not yet appear to have found a way to adequately explain to non-experts is the vast knowledge void that remains to be filled between scientific understanding of the emergence of life and the emergence of intelligence in life.” This is still the case.
I read Cabrol’s paper as part of a strategy to further blur the boundaries between astrobiology and SETI and reframe SETI as a scientifically valid research enterprise.
Cabrol and her colleagues in the SETI community place SETI firmly within the boundaries of the field of astrobiology. Yet SETI is not recognized as a research priority in either the astronomy and astrophysics or planetary science “decadal surveys” conducted for NASA by the National Academies. And at NASA, SETI is not within the boundaries of astrobiology. SETI is not addressed in the new NASA astrobiology strategy published last year, nor was it mentioned in preceding astrobiology “roadmaps” (published in 1998, 2003, and 2008). (Disclosure: My work is funded in part by NASA’s astrobiology program. No one asked me to write this post.)
In a 2003 report, Life in the Universe: An Assessment of U.S. and International Programs in Astrobiology, the National Academies’ Committee on the Origins and Evolution of Life (COEL – now known as the Committee on Astrobiology and Planetary Sciences, CAPS) observed that SETI “represents the most romantic and publicly accessible aspect of the search for [ET] life, yet is perhaps the most problematic…. COEL sees no merit in debating the validity of a search whose negative results arguably tell us little about the ubiquity of life. The debate has no merit because the foundational motivation for the search in the popular aspiration to communicate with other forms of intelligence as much like or unlike us as we can imagine.” The committee concluded that SETI should continue seeking private funding.
“Since 1961,” Cabrol writes in her paper, “SETI’s intellectual framework has been centered on a probabilistic argument, the now-famous Drake equation…. Consisting of a combination of quantitative and speculative factors that were solely meant to engage a discussion within the scientific community on the potential number of extraterrestrial civilizations willing and able to communicate in our galaxy, it quickly became SETI’s signature…. The term equation is misleading…. For instance, between fi and fc the notion of intelligence abruptly gives way to that of civilization, when they are, in fact, distinct notions. On our planet, one has not been demonstrated to necessarily lead to the other.”
I agree. In previous writings, including a recent paper (“The allure of alien life,” in S. Dick, ed., The Impact of Discovering Life Beyond Earth, Cambridge UP, 2015), I have critiqued the squishiness of this so-called “equation”: “SETI’s goals and objectives rest upon a considerable number of assumptions – for example…that intelligence is an inevitable product of evolution, that extraterrestrial intelligence would inevitably produce technology like human technology, and that extraterrestrial intelligence or technology would be recognizable to terrestrial intelligence.” So this so-called equation “is merely a heuristic tool, an approach to roughly “guesstimating” how many planets in the Milky Way galaxy might host intelligent life…. [A] product, the number of communicating civilizations in our galaxy, is impossible to calculate, and guesstimates range from zero to billions.”
In a June 24 article for the Huffington Post, anthropologist John Traphagan offers further thoughts on the limitations of this heuristic: “When SETI scientists imagine extraterrestrial civilizations, they usually think in terms of unified worlds that have one civilization. The image is very much unlike our world, in which we have multiple civilizations that are fractured and in conflict with other societies….”
Cabrol says SETI’s rationale “remains largely unchanged today despite advances in exploration and science that are relevant to the factors of the equation.” I certainly agree. She calls for an “expanded vision,” beginning with an acknowledgement “that so far, in our quest to find ET, we have only been searching for ourselves.” Again, I agree. Then she goes on to say, “The evolutionary pathways that lead to complex life on Earth strongly suggest that advanced life as we know it may be rare in the Universe and unlikely to be in a state of advancement that is temporally synchronous with us. However, that does not mean that other types of advanced intelligences are as rare…” (Hmmmm…)
Cabrol also claims that “searching for other versions of ourselves is not unique to SETI. This is equally true of astrobiology.” I would disagree with this claim. While SETI is, indeed, at least to date, looking for other versions of ourselves, astrobiology is exploring what makes an environment habitable, how life and environment have co-evolved on Earth, and what biochemistry might be like on planets unlike Earth. (For further details of what astrobiology is about today, see the science strategy cited above. Also see my 2012 paper in Astrobiology, cited above, in which I noted that “at the same time that research into the origin, evolution, and distribution of life is revealing that life is highly resilient, these same lines of research are helping to reveal how life and its environment are deeply interdependent, improving understanding of life on Earth and prospects for life elsewhere, and contributing to understanding of global climate history and evolution.”) Also see the National Academies’ Committee on the Origin and Evolution of Life report (2007), The Limits of Organic Life in Planetary Systems, known in the community as the “weird life” report.
“Now is the time for SETI to develop a roadmap and longterm [sic] vision that includes the search for life as we do not know it,” Cabrol concludes. “New tools are available that can enable this approach and help us decipher the evolutionary and probabilistic nature of advanced alien life…. All of them must be deployed when thinking about who, what, and where ET could be, and how it might communicate.”
I read this new approach as a more sophisticated way of describing how to search for ourselves. (See my blog post of July 12. At a congressional hearing just yesterday, SETI scientist Shelley Wright said, “The key factor in the Drake (heuristic) is L, the lifetime of a civilization. We are in our technological infancy, she said, and other civilizations could be hundreds of thousands of years older than ours.”)
To achieve this new “vision” for SETI, Cabrol says, “requires the exploitation of multidisciplinary synergies and an intellectual framework with a clear agenda and milestones. A similar intellectual and logistical structure was successfully established 20 years ago by NASA with the creation of the NASA Astrobiology Institute (NAI) for the understanding of life on Earth and beyond. However, past and present astrobiology roadmaps have not put substantial emphasis on alien intelligence, communication, or technology. In the coming months, the SETI Institute will be initiating efforts in this direction, and will invite the United States and international research communities to contribute to the drafting of a new scientific roadmap for SETI. We will explore resources for the development of a virtual institute and an intellectual framework for multidisciplinary projects specifically focused on the advancement of knowledge on ETI. Complementary to, and different from, the astrobiology roadmap, this vision will bridge the NAI roadmap [LB: the NAI does not have a roadmap – the NASA astrobiology community produced, and NASA endorsed, the 1998, 2003, and 2008 roadmaps and the 20-15 astrobiology strategy], augment it, and go beyond it. Its primary goal will be to ‘Understand how intelligent life interacts with its environment and communicates.’’”
The SETI community is definitely in need of a new roadmap. According to the SETI Institute’s roadmap, “SETI 2020,” published in 2002, “SETI has important implications for the future of society on Earth…. The actual discovery of a signal will lead to sociological, intellectual and practical changes in our civilization.” As I noted in my 2015 paper, “These claims, couched as certainties, are, at best, speculations. To accept them as certainties requires an embrace of the ideology of SETI, [a] belief system…reminiscent of messianism, millenarianism, anarcho-communism, and utopianism – ideologies that fostered hope for social change, salvation, a new way of living.”
As to what will come of the SETI Institute’s new campaign, we shall see.
* The SETI Institute’s Carl Sagan Center oversees research funded in large part, if not in total, by government (mostly NASA) grants. The work of the Institute’s Center for SETI Research is privately funded.