Last week, the U.S. National Aeronautics and Space Administration (NASA) landed its rover, Perserverance, on Mars. It is the latest in a series of human efforts now spanning six decades to physically explore and travel to parts of the the universe beyond our terrestrial home. Scientific and engineering matters tend to dominate public discussion of these efforts, yet there are a wide range of philosophical questions about space exploration, too, and philosophers have been working on them.
“Philosophy of Space is in much the same position as Philosophy of Biology was in the 1980’s—largely ignored by traditionalists, but with enormous potential for new and exciting work.” Those are the words of Kelly C. Smith, professor of philosophy at Clemson University, who works on philosophical issues surrounding the search for life on other planets. Philosophy of space involves such fascinating issues, yet, like space itself, is relatively unexplored by humans.So I asked Professor Smith to put together an edition of “Philosophers On” to introduce readers to some of these issues. I’m grateful to him for organizing and editing this post, which includes contributions from him, Brian Patrick Green (Markkula Center for Applied Ethics, Santa Clara University), Chelsea Haramia (Philosophy, Spring Hill College), Carlos Mariscal (Philosophy, University of Nevada, Reno), and Jim Schwartz (Philosophy, Wichita State University).
As with previous “Philosophers On” posts, the contributions are intended not as comprehensive statements or final words, but rather as brief prompts to further discussion of the issues here and elsewhere. The idea is to explore ways philosophers can add to public conversations about topics of current interest, as well as spur further discussion among philosophers about these events. As Professor Kelly says below, he hopes the post will “pique the interest of the wider philosophical community and inspire more to examine the many questions raised by the coming space age.”
- “Philosophy of Space Reaches Puberty” by Kelly C. Smith
- “Ethics in Space” by Brian Patrick Green
- “How Should We Search for Intelligent Life in the Cosmos?” by Chelsea Haramia
- “A Pragmatic Account of Universal Biology” by Carlos Mariscal
- “Space Policy as a Prompt for Philosophy: The Example of Planetary Protection” by Jim Schwartz
Philosophy of Space Reaches Puberty
by Kelly C. Smith
Humanity stands at the brink of the space age. Of course, this was also said in the 1960’s, but then it was more an expression of enthusiasm for our very first steps into space. The frenetic pace of missions, discoveries, and new technologies in recent years mark the end of this beginning and the start of…something, we know not what. Consider a few landmark achievements in just in the last few years:
- Discovery of the first “exoplanet”, which now tops a list of over 4,400 (some potentially habitable)
- The discovery of an asteroid estimated to be worth 10,000 quadrillion dollars
- Solid evidence of liquid water (thought to be critical for life) on several bodies in our own solar system
- The first paying tourist in space
- The germination of the first terrestrial plant on, as well as the first major biological contamination of, another world
- The departure of the first human probe (Voyager I) from humanity’s home system, with greetings from Earth on its “golden record”
This is not your parents’ space race. In particular, as the price of admission continues to drop, we will see more and more involvement by private individuals with their own agendas. For example, a Russian billionaire is funding a series of projects, including a “Starshot” mission to our nearest neighbor, Alpha Centauri (which appears to contain habitable planets). The Interstellar Beacon Project aims to beam the contents of Wikipedia to thousands of potentially inhabited systems and is funded by a mere millionaire. This activity is almost entirely unregulated, raising the very real possibility of a “wild west” in space.
Of course, the most philosophically explosive development would be the discovery of extraterrestrial life (ETL). NASA currently predicts that we will find evidence of ETL within the next few years, which would surely rank as the most important scientific discovery ever made. The array of complex social, ethical, and conceptual questions this would raise is enormous, though curiously there has been little sustained investigation by the wider academic community. There are, of course, good reasons for caution. Astrobiology at present has an ineliminable speculative element, since it has as of yet no alien organisms to study. But there are many questions about our future in space which, though raised in radically new contexts, are amenable to traditional humanistic analysis right now (e.g., environmental ethics, property rights, etc.).
And even questions about ETL that lack the kind of empirical basis we prefer do not lack strong theoretical underpinnings. The famous Drake equation frames the likelihood of ETL in scientifically tractable terms, and a recent calculation suggests that it is vanishingly unlikely terrestrial life is unique. This should not be surprising, given the evolutionary view of life as a natural outgrowth of chemistry and the ubiquity of all the necessary ingredients (see Mariscal’s post in this series). The force of the theoretical argument is not always fully appreciated, so let’s assume for a moment that life were unique to Earth. That would mean a huge chunk of our current scientific understanding is not just wrong, but fundamentally wrong. It would also force us to reassess many aspects of how we see ourselves that we have long taken for granted. For example, is there really a meaningful distinction between saying life evolved via natural processes, but only once (despite trillions upon trillions of inviting opportunities) and saying it’s a miracle?
To be sure, it’s especially important for new scholarly endeavors to impose limits on speculation and uphold rigorous standards. One major problem astrobiology faces is the inevitable comparison to the UFO craze. The basic problem with “Ufology” is that it begs the question by starting with the belief it purports to establish (that aliens not only exist, but regularly visit Earth). However, it’s important to keep firmly in mind that there is absolutely nothing unscientific about hypotheses involving aliens when these are consistent with the best available evidence, as may be the case with the Oumuamua object. In other words, we should be wary of being overly credulous, but also of adopting a cramped empiricism which refuses to seriously consider the possibility of ETL until the evidence is irrefutable.
The purpose of this series is to pique the interest of the wider philosophical community and inspire more to examine the many questions raised by the coming space age. If we are to avoid a dystopian future, we need to begin thinking about these issues now, before they are reified in established practice (much as ELSI did with genetic technology). I submit that Philosophy of Space is in much the same position as Philosophy of Biology was in the 1980’s—largely ignored by traditionalists, but with enormous potential for new and exciting work. The reward for first adopters is a seat at the table as an entirely new field is being shaped. It was with an eye toward establishing a supportive community for this work that the Society for Social and Conceptual Issues in Astrobiology (SSoCIA) was founded in 2016, which has since held three international conferences and grown to include over 100 scholars from a wide range of disciplines. If you are interested in joining our intrepid band, I invite you to look at our most recent conference proceedings and join our listserv.
Ethics in Space
by Brian Patrick Green
There is some urgency in the area of space ethics, and the work of SpaceX corporation is instructive: Elon Musk is proceeding to Mars as fast as he can, for the sake of preserving a “backup” for humanity in case an existential risk destroys human civilization on Earth. Ethics should keep up with—or preferably stay ahead of—this rapidly developing area of scientific and technological advance, or else humankind risks blundering into enormous and irreversible mistakes. Here I will give a brief overview of a few ethical issues related to space.
The first ethical issue is whether humans ought to go into space at all. There are plenty of arguments against human space exploration in particular, e.g., the cost of it, the well-known risks to human life and health, and the justice of using funds for space and not for other more immediate problems here on Earth. The arguments in favor of exploring space involve developing science and technology (and indeed space exploration has already resulted in incredible gains in knowledge and technology as well, such as GPS), preserving the human species (and other Earth life) off-planet in case of existential disaster, and seeking human purpose in the cosmos. But we have to ask, ethically, is it worth it?
Another set of ethical issues involve the military value of space. Militarily, space is the “ultimate high ground” (“Semper Supra” or “Always Above” is the motto of the new US Space Force), and makes for a tempting location for weapons platforms and weapons of mass destruction. While these are banned by the 1967 Outer Space Treaty, the temptation to do it anyway may strengthen over time.
Certainly ground-based weapons are already targeting satellites for destruction, and even a limited space war in low Earth orbit could quickly lead to a debris cascade. Orbital debris is already increasing over time, and if it reaches a certain threshold, it will spark an exponentially growing process—the “Kessler Syndrome”—which could make space inaccessible from Earth. Indeed, we may already be at the beginning of such a cascade and not yet recognize it. Outer space is a new space for environmental ethics, and the unfolding tragedy of the commons a few hundred miles over our heads should be solved sooner rather than later.
There are several types of civilization-threatening space-borne disasters including asteroid and comet impacts, coronal mass ejections causing geomagnetic storms, and supernovae and gamma ray bursts. Mitigating these threats is possible but complicated. For example, given enough time to prepare, humanity might now be capable of preventing an asteroid impact, thus potentially eliminating an entire class of threat to our planet. This is a huge and new ethical responsibility, affecting not only the well-being of human civilization, but the ecosphere as well. However, with the power to divert also comes to power to target, and so these technologies also push us closer to a future where asteroids can be used as weapons of super mass destruction. This dual-use potential for space technology ought to promote more thought and action about how to make human civilization safer from these types of risks, including via space settlements.
And the question of space settlement brings us back to SpaceX. Many new players have entered space in the last few decades, but private companies like SpaceX present special challenges. Currently, the Outer Space Treaty puts all subnational actors under the jurisdiction of their sending nation, but SpaceX (through an odd bit of language in its Starlink satellite internet contract) has already expressed that they might not be planning to follow this law, stating that the parties of the contract “recognize Mars as a free planet and that no Earth-based government has authority or sovereignty over Martian activities.” Musk has also stated he wants to terraform Mars, which brings us to another issue.
Any settlers on Mars might well desire to warm the frozen desert planet, and ideas for technology already exist to rapidly do so, with one paper saying it can be done in 100 years. This will not make a breathable atmosphere, but it will release immense quantities of carbon dioxide and water, which will raise the temperature, humidity, and atmospheric pressure to more Earth-like levels. This would also dramatically alter Mars’ current environment and destroy much scientifically irreplaceable evidence of its natural history. If there is any life on Mars, it would be affected as well, perhaps to the point of annihilation. Needless to say, changing the habitability of a planet is a godlike power, and one that ought to be wielded with great care.
There are many more topics in space ethics. For example, in this series of posts, Schwartz and Haramia discuss planetary protection and extraterrestrial intelligence, respectively. The possibility of extraterrestrial life involves other complex ethical issues, such as the nature of its moral value, how we ought to relate to it, and so on. And, of course, there are huge philosophical questions about what humankind’s role and purpose in the universe is or should be (if there even is such a thing). In my forthcoming book, Space Ethics (Rowman & Littlefield International), I go into all of these topics in more detail.
How Should We Search for Intelligent Life in the Cosmos?
by Chelsea Haramia
Either we’re alone in the universe, or we’re not. If we’re not, then we might someday come into contact with other intelligent life. ‘SETI’ stands for ‘Search for ExtraTerrestrial Intelligence,’ and SETI practitioners have historically engaged in a largely passive search for ETI—listening for alien transmissions. More recently, some researchers have taken up a more active approach known as ‘METI’ or ‘Messaging ExtraTerrestrial Intelligence.’ They are intentionally sending high-powered cosmic beacons into interstellar space, attempting to elicit a response. Both projects raise a host of ethical questions, especially recent METI projects, which are much more powerful and targeted than past messaging activities.
For example: Who should speak for Earth? Historically, it has been astronomers themselves. Notably, earlier messages (such as the Voyagers’ Golden Record or the Arecibo Message) were primarily symbolic or ceremonial in nature. Presently, however, the goal of METI is to expedite communication with ETI, and the opportunity to speak for Earth is available to anyone with access to sufficiently powerful equipment. One worry is that those who speak for Earth—past and present—are not exactly a representative bunch, yet the project involves speaking on behalf of all humanity. Properly communicating on behalf of humanity may require more-inclusive representation, along with a concerted effort to amplify the voices of members of non-dominant groups.
The above debate presumes that it’s time to speak up. But another important ethical question is lurking here: Should we be announcing our presence in the cosmos? We simply do not know what to expect from an ETI, and it’s possible that they will be hostile or unintentionally harmful. The effects of contact could negatively impact everyone. This raises the concern that METI projects impose globally catastrophic risks on humanity without humanity’s consent. Of course, there’s reason to think that achieving global consent would be practically impossible. However, there may be an ethically defensible degree of consent that’s worth aiming for, even if comprehensive agreement among all members of humanity were out of the question. Beyond that, we may bear obligations to those whose consent is impossible to gain, e.g., plant and animal species, or future generations. And given the lag times involved in signaling even the nearest stars, future generations stand to be impacted the most by any effects of contact.
Another way for the METI proponent to respond to the challenge from global catastrophe is to flip the risk question. There are a number of catastrophic possibilities that threaten humanity or the Earth that don’t involve aliens. Human-caused climate change is one. Supervolcanoes and asteroids are others. METI proponents point out that communicating with ETI might be the advance that gives us the tools, knowledge, or capabilities needed to effectively ward off other global threats. There may be many other benefits of contact as well. The point is that it’s at least possible that not contacting ETI would lead to the destruction of humanity or the Earth. Therefore, abandoning METI also risks catastrophic outcomes.
This can start to feel like an impasse. Both engaging in and abandoning METI projects carry a non-zero risk of global catastrophe. And so, it is difficult for both METI proponents and METI critics to successfully appeal to particular harmful outcomes when attempting to justify their respective positions.
But there remains an important ethical consideration available to the global citizen who is concerned about risk. On the one hand, passively searching gives us the time to evaluate carefully before committing to communication. This inherently allows for more caution, and it still preserves the possibility that we may someday benefit from communication with an ETI. On the other hand, METI’s active approach effectively rules out this opportunity—once the signal leaves Earth, it cannot be stopped, and we can only speculate about who might receive it. Thus, active messaging carries risks that the alternative doesn’t. But this does not mean that passive searches ensure that we decide how detectable or at-risk we are.
Passively searching does not automatically provide us with a cosmic cloak, nor does it guarantee an opportunity to evaluate an ETI before making our presence known, even if it’s our best shot at doing so. Our presence may already be detectable because we’ve been unintentionally leaking our own technosignatures for decades (e.g., radio and television broadcasts), and Earth itself has been displaying biosignatures for billions of years. At the same time, extraterrestrial astronomers would have to be especially savvy to have detected us already. Biosignatures seem to be quite difficult to detect. Our unintentional radio signals do travel, but they haven’t traveled very far yet, cosmically speaking, and they diminish exponentially in strength as they go. And if it turns out that we’ve already been detected or observed without being contacted, it might be that aliens have decided that humanity is simply not ready to join the galactic community.
A Pragmatic Account of Universal Biology
by Carlos Mariscal
The only life we know is on Earth. It is a quirky phenomenon, but whether those quirks are unique to our corner of the galaxy or like what we might find elsewhere in the Universe is an open question. Most biologists are not used to thinking about the implications of their research for life elsewhere; most biology is local. By contrast, we might ask whether any principles of biology would apply more generally than Earth: universal biology. In short, universal biology is the study of life as it must be everywhere in the Universe. We may never be in a position to conduct universal studies to a philosopher’s satisfaction, but work in astrobiology suggests we may be in a position to explore the matter now. There are two questions immediately invoked by the concept of universal biology.
- In what sense is universal biology universal? In other words, which properties or principles of biology are likely to be common, which are exceptionless, and where should we look for them?
- In what sense is universal biology biology? The answer to this question will either require a deeper understanding of the concept of ‘life’ or an explanation of what stand-ins we can use that can still shed light on the issue.
Let’s start with the first question: how is universal biology universal?
The more we learn about astrobiology, the more plausible it is that Earth is not unique in many ways, making it very plausible that biological entities exist elsewhere. Supposing that is the case, in what ways are they likely to be similar to Life on Earth? Even before the development of astrobiology as a discipline, this has been a serious question and there are many topics that intersect with it. For example, philosophers have wrestled with the question of whether biology has laws, whether they be exceptionless universals, exception-riddled generalizations, or merely models that apply more broadly than Life’s history on Earth. Biologists have approached a similar issue in drawing broad conclusions from biological principles, such as the Zero-Force Evolutionary Law or generative entrenchment, which dictate null expectations of evolution and development, respectively. Astrobiologists might even apply other sciences to biology and observe that the chemistry of the Universe is fairly well understood, which, in turn, constrains the biochemical possibilities for life. Each of these topics fits within the broader topic universal biology, though connecting them and their implications is a much larger task.
Let’s turn to the second set of questions invoked in universal biology: those about the domain of the topic, namely ‘life.’
Every organism on Earth shares common ancestry, as evidenced by a shared genetic code. Life on Earth is a peculiar phenomenon, but in many respects it is not unique. It (or its parts) evolve, metabolize, are in thermodynamic disequilibrium, etc. and there is no reason to believe that those features are unique to this corner of the Universe. Rather, it’s plausible that similarly situated physical systems would result in relevantly similar phenomena.
Some philosophers and astrobiologists have interpreted one or more of the properties of life as definitional of life itself. To these researchers, universal biology is the study of their favorite property under the expectation that life elsewhere will also share that property. Too much ink has been spilled in this fight (including some of my own), for me to spend much time on it here (though see here). Suffice it to say, there is wide disagreement about what, if anything, defines life. Still, if no theoretical definition of life is possible, investigating the properties of Life on Earth might remain a worthwhile endeavor. Such investigations might inform us about Life-like phenomena elsewhere even if they cannot reveal the essence of life in general.
Curiously, those most skeptical of universal biology are philosophers and scientists who accept life on Earth as a member of some as-yet-unknown natural kind. They believe it is more prudent to wait until astrobiologists discover new instances of life before we begin conjecturing about universal biology (for more on this debate, see here and here).
I accept Life on Earth is a member of many categories: evolving lineages, metabolizing entities, informational systems, squishy things, etc., but I am quite skeptical of any essences or defining features of life. I don’t believe any natural category will be co-extensive with what scientists or the public will accept as ‘life.’ As such, I label as ‘universal biology’ most of the work done investigating the nature of evolution, information, metabolism, etc. Because the scope of these studies is universal, the potential for counterexamples for any particular view will never be quenched. Let many flowers bloom in our quest for universal features of biology, even if the practitioners never come to a consensus view. An investigation of universal features that apply to Life on Earth is universal biology enough.
Space Policy as a Prompt for Philosophy: The Example of Planetary Protection
by Jim Schwartz
“Planetary protection” is a policy tool for (a) protecting Earth’s life from harmful contamination from extraterrestrial sources (AKA back contamination – think Andromeda Strain), and (b) protecting sites of interest in the search for evidence of extraterrestrial life (including traces of past life) against contamination from terrestrial sources (AKA forward contamination). Here I will focus on protection against forward contamination, as (so far) this has proved to be the more philosophically interesting of the two.
The need for forward protection was recognized in the 1950s, before humans had even placed a satellite in orbit. The underlying concern is that it would be terrible to “discover” alien life on worlds like Mars, Europa, or Enceladus, only to realize later it was just some terrestrial microbes that had stowed along for the ride. COSPAR (the Committee on Space Research) routinely updates its planetary protection policies, which are widely used for science missions, though they do not carry the force of law. These specify protocols and bioburden reduction strategies based on mission-type (flyby, orbiter, lander, impactor) and intended destination (Moon, Mars, Ceres, etc.).
Philosophically interesting questions appear immediately: What do these efforts assume about the nature of life? How can we determine whether a space environment is habitable (or even potentially habitable) given that we do not fully understand the boundary conditions for life? How effective are COSPAR’s policies? Should their scope be expanded or narrowed?
Characteristically ethical questions lurk nearby: What is the moral status of alien life? Which kinds of life (microbial, multicellular, intelligent) should be accorded moral value and of what sort (intrinsic, instrumental, etc.)? Does it matter whether this life represents a distinct evolution of life? What effects will analyzing the moral status of alien life have on theories and concepts in normative and metaethics? Should planetary protection focus on potential obligations to alien life in addition to/instead of its current focus on protecting opportunities to study that life? (For more on space ethics, see Brian Green’s post; also here and here.)
More broadly, should our focus extend beyond alien life? There are many bodies in the solar system that we do not think are even potentially home to life. What sort of environmental ethics do we need for exploration of such bodies? Is the value of “lifeless” places exhausted by their instrumental value to planetary science or do they have value in their own right, though perhaps of another kind?
There is a growing need to consider expanding the scope of protection policies. Space science sits in an evolving context where commercial actors (such as SpaceX and Blue Origin) are playing increasingly prominent, agenda-setting roles, and with significant cultural, financial, and political momentum supporting the exploitation of lunar and asteroidal resources and human settlement of the Moon and Mars. However, legal instruments like the U.N. Outer Space and Moon treaties were crafted before momentum-shifting discoveries about space resources (e.g., asteroids like 16 Psyche that are potentially worth trillions of dollars). Can the goals of space science be reconciled with the goals of commercial actors? If we wanted to create a policy to protect sites of interest to planetary science, or a general framework for environmental protection, would we even know how to do this or what is worth protecting? What level of protection would be reasonable given competing stakeholder interests?
The Moon, rather than Mars, will probably be our first “case study”. The Moon’s polar regions offer two critical resources: The basins of permanently shadowed craters are home to a limited, non-renewable quantity of water-ice (potentially useful for drinking, watering crops, and electrolyzing for rocket propellant); and the rims of some of these craters receive nearly uninterrupted sunlight (useful for solar power and solar observation). The poles are thus places most everyone wants to visit, suggesting we may soon see intense competition between the various actors to secure them for their own purposes.
The Moon is a precious object for scientific study. Lacking plate tectonics, its structure and composition have remained largely the same for much of its 4.5 billion years of existence. Its surface cratering preserves a record of the early history of the solar system. This means that studying the Moon will inform our understanding of the evolution of the solar system, especially the inner solar system. While pursuing fundamental science questions is a major theme of the Lunar Exploration Roadmap, so too is the use of the Moon as test-bed for crewed missions to Mars and for eventual human settlement. Are these goals compatible? If not, which should be prioritized? (In The Value of Science in Space Exploration I argue at length that science goals should be prioritized over non-science goals in space.)
The Moon is also culturally significant. It is a fixture of our night sky visible to every human who has ever lived, we have named many of its prominent features, we have visited it robotically and in person, and we have left our trash there. Do we need to think about protecting cultural heritage sites on the Moon? Who should be consulted if we wanted to do so? Is NASA’s guidance adequate? What should be our response to serious proposals to erect or project advertisements on the lunar surface?
Of course, planetary protection, and by extension, space environmentalism, are not the only philosophically interesting space policy topics. To name just a few, orbital allocation regulations, space debris mitigation guidelines, and space science/mission decision-making processes each provide similar playgrounds for philosophers.