Research
updated 9/20
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Ok, so if you just want to see a hyper-detailed list of everything I have ever done, check out my curriculum vitae (an academic resume) here.
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For those of you who want more context, below I offer a semi-autobiographical account of the various research projects I've taken on over the years and how I got interested in each one. I organize this as a series of big questions, followed by a brief account of the kind of answers I have formulated. I provide links where I can, though in a couple of cases there are inactive links (e.g., when the publication in question is still under embargo) - just ask me if you want to see one of these. All this is also roughly in chronological order, with my current work towards the top and my early career stuff down at the bottom.
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Click on a question from the list to jump to it
Astrobiology Stuff
Q: What does philosophy have to do with astrobiology?
Q: What are our ethical obligations to alien life?
Q: Under what circumstances is it OK to attempt to contact extraterrestrials (METI)?
Q: Should humanity be seeking to colonize other worlds?
Q: What is the point of life, the universe and all that?
Teaching Ethics
Q: How should we teach ethics?
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IEvolution and Creationism
Q: What is the deal with creationism and what should we do about it?
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Theoretical Biology
Q: What does it mean to describe a trait as "genetic"?
Q: Do "developmental systems" explain traits?
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Q: What does philosophy, and the humanities more generally, have to do with astrobiology?
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Quite a lot, actually. As I often tell students when I discuss my work: every discipline has a theoretical fringe and philosophy can often help clarify the issues here, even solve knotty problems from time to time. For example, I've worked on questions in biology that biologists admit are important (e.g., What is a "genetic" trait?) and even foundational (e.g., What is 'life'?). But, while scientists may discuss these things with their grad students over beer, they have labs to run and grants to write and, when push comes to shove, producing papers on weird theoretical questions, even super important ones, will not advance their careers (though once they get super famous they tend to reverse course and muse about exactly these issues). In any event, I discuss the kinds of challenges people like me face sometimes from their scientist colleagues and outline some ways we can help astrobiology in "Got Humanities?", an invited commentary for the leading astrobiology journal, and also in a piece for The Philosopher's Magazine called "Philosophy in Spaaace!".
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Q: What are our ethical obligations to alien life?
If such life is microbial, as is almost certainly the case for extraterrestrial life that we may find any time in the next 20 years or so (like on Mars), I argue that we can do anything with it that serves significant human interests. That doesn't mean it's ok to do anything any human might think is a good idea, since if nothing else this kind of life would have incredible scientific value that we should be careful to preserve. Nevertheless, if a significant benefit for humans (who clearly have high moral value) is pitted against a significant benefit for microbes (who may not have moral value at all and, if they do, a far lesser one), it's actually immoral to constrain our ability to exploit (yes, I know that's a loaded word) alien life for human ends. In "First Do No Harm: Ethical Limits of the Prime Directive", a popular piece I published online in The Conversation, I outline my reasoning (with about 62,000 reads at last check, it outstrips all my more serious work combined by a couple of orders of magnitude - such is academia). In "The Curious Case of the Martian Microbes", I argue essentially the same thing but in a more sustained way (and coin the term "Mariomaniacs" for Mars huggers who go too far). For you Star Trek fans, this is also where I point out how moronic the Prime Directive is as an ethical guide. I also served as an ethics expert for the recent student competition NASA sponsored where students debated exactly this question, and you can watch the video of me in those two interviews if you want.
So microbial life is up for grabs, more or less. On the other hand, the more life exhibits the kinds of rational character (yes, I am a bit of a Kantian here) that's necessary for moral reasoning, the more ethical value it has (roughly speaking anyway). Thus, if we encounter extraterrestrials that are as rational as we are (whatever that means exactly), then we should treat them as our moral equals. This has nothing to do with, incidentally, whether they are biological or machine - it's the capacity, not the form, that matters. Early versions of this kind of argument using the standard intrinsic/instrumental value distinction can be found in "The Trouble with Intrinsic Value: An Ethical Primer for Astrobiology" and "Cosmic Ethics: A Philosophical Primer". Lately, though, I have come to a more naturalistic justification, as you can see in "Manifest Complexity: A Foundational Ethics for Astrobiology?". Finally, though I haven't discussed it in print yet, my current view is not so much about rational capacity as it is about membership in a community.​
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Q: Under what circumstances is it OK to attempt to contact extraterrestrials (METI)?
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It may sound like science fiction, but serious people are doing this right now: see this video about a recent transmission and a video discussing the pros and cons here (this was produced with Clemson students, then used to conduct a survey of student attitudes that I am still working up for publication). Not many know about it yet, but we are beginning to see serious debate in the space community about whether this is a good idea. Thing is, almost all the work on this so far has been done by space scientists, who are really smart and generally well-intentioned, but tend to be completely clueless concerning the ethical principles guiding human research. Instead, they debate what they know, which means 95% of the literature on METI focuses on the level of risk posed by attempting to contact aliens, and quickly gets sidetracked into technical questions about the power of transmissions, the putative detectability of Earth's electromagnetic leakage, etc.
Of course, we do need to know all this empirical stuff, but in this case it completely misses the ethical point. My addition to the field consists of trying to change the focus with this simple argument: given that there is some risk of a catastrophic outcome if we do this, and given that we have nothing like the consent of those potentially impacted (all of humanity), it is simply immoral to proceed (at least without clear safeguards and review processes in place, which don't exist at all right now). Sadly, so far anyway, the "let's transmit now" enthusiasts are winning, since there are several serious projects underway right now to do it (sigh). You might check out a particularly disturbing example, which aims to broadcast the entire contents of Wikipedia (!) to thousands of star systems here. My definitive work on this is "Meti or Regretti: Ethics, Risk and Alien Contact" (link not yet active) which just appeared in my new anthology that you can actually buy here if you have $44 to blow. However, a brief version of my main argument can be found in "Hawking and the METI Hawks: Right for the Wrong Reason". A related piece, is "A(nother) Cosmic Wager: Pascal's Wager and METI", which addresses one common type of counterargument to METI skepticism (the barn door argument) by comparing it to Pascal's Wager about belief in God, of all things. Finally, I talked about this stuff with a couple of my professional colleagues when I was a guest recently on NPR's Science Friday with Ira Flatow.
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Q: Should humanity be seeking to colonize other worlds?
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There are a number of variations on this question and a range of positions. For example, you could argue for a fairly limited kind of "lifeboat" on another world - not really a full fledged colony but rather just enough stuff (an archive of all human knowledge, some frozen embryos and a skeleton staff) to rebuild human civilization on Earth should disaster strike, as I do in "The Terrestrial Lifeboat Project: An International Undertaking to Safeguard Humanity". You could also argue for an evolutionary imperative of sorts by pointing out that populations and societies which establish colonies have more diversity and, as a consequence, are better able to deal with unexpected challenges, as I do in "Cultural Evolution and the Colonial Imperative". You could even go nuts and flirt with a full on "manifest destiny" type of argument that says humans have a moral obligation to colonize space as I do in "Homo Reductio: Eco-Nihilism and Human Colonization of Other Worlds" It's fair to say that my position is out on one end of the continuum, so if you want to gain some insight into other scholars' views, check out "The Great Colonization Debate" an informal exchange I organized featuring 15 experts with widely divergent views on the subject.
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Q: What is "life" anyway?
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Life is what got me into astrobiology to begin with. Way back in 2004, NASA and the American Association for the Advancement of Science (AAAS) sponsored a workshop to think through what life is and how we might go about finding it on another world. They invited some oddballs to keep the conversation interesting, including one token philosopher, who was a friend of mine. He couldn't go, but he recommended me as a replacement. I had not worked on this at all before, but liked the idea of an all expense paid trip to Washington, DC. So I got to sit around a big conference table for 3 days with some super smart NASA folks (who were all, like me, big Star Trek fans). I had lots of fun and decided this was a field worth getting into - the rest is history.
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"What is life?" is a good example of a philosophical puzzle: a question that seems really easy to answer until you actually try. Of course, we all know what life is - sorta. We recognize it all around us and every biology textbook has a "definition" of life in the very first chapter. But if you believe there is life elsewhere in the universe (as NASA clearly does), then you have to wonder just how adequate such definitions are. After all, the "definitions" in textbooks are basically just lists of properties that are common to life on Earth. But is it really necessary that life use nucleic acids or be composed of cells? Of course, we may all readily agree that something as general as "metabolism" is probably necessary for all life anywhere in the universe. After all, you gotta get energy from somewhere and if we define "metabolism" vaguely enough, we can be confident any other life we find will be "metabolic". But showing something meets such a generous definition doesn't do a lot of work and results in questions like, "Is the sun alive?" I mean, it has a metabolism of sorts, right? More than that, it is "born" and "dies" - heck, it even "reproduces" in a "heritable" way (when it blows up, it seeds the area around it with its own unique distribution of heavy elements). It's easy to blow off such speculation as absurd, but I challenge you to try explaining exactly what your reasons are for doing that. If you can't, how do you know you aren't just a knee-jerk Earthist?
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There's a reason we don't have an agreed upon conception of "life" - different people have different ideas about how to use the term (which is even true amongst scientists - physicists disagree with chemists who disagree with biologists). Defining "life" is thus super hard. Initially, while I had ideas about what life was, I didn't have anything concrete enough to publish. But there was one other American philosopher working in astrobiology at the time, Carol Cleland, who argued that we should stop trying to define life at all. I might not know what life is, but I knew this was fundamentally wrong-headed (a good disagreement warms the heart of any true philosopher). So I worked up a response to Carol in "Life is Hard: Countering Definitional Pessimism Concerning the Definition of Life". Of course, it's much easier to be negative than positive, and it was a long while before I was ready to publish my first tentative account of what life actually is with "Life as Adaptive Capacity: Bringing New Life to an Old Debate." While I think this makes some good points, it's clear that after 14 years of thinking about life, I still have a lot of work to do before I can say I've solved the puzzle to my own satisfaction.
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Q: What is the point of life, the universe and all that?
This is the really, really big question that occupies a good chunk of my attention these days. The definitive answer is going to take a large and complex argument that delves into philosophy, physics, origins of life, ethics, complexity theory, theology and a few other fields. So you will have to wait until my magnum opus appears to learn the answer. However, I do have the germ of an idea which my book will eventually explore in great detail. It may be wrong, but (as one of my colleagues put it) even if it is, it's clearly wrong in an interesting way. In other words, it's one of those ideas whose careful investigation should advance the field even if my specific arguments do not stand the test of time.
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As you have seen if you read all the above, I argue that rationality is the hallmark of high moral value. Most ethicists who agree with me on this stop there, but I put on my evolutionary biologist hat and want to know how rationality comes about, since I suspect the answer to this might have a major impact on ethics. So in "Manifest Complexity: A Foundational Ethics for Astrobiology?" I float the hypothesis that evolution naturally and predictably produces three features together: rationality, sociality, and culture. In other words, if you take 1,000 planets, all suited for life, and leave them alone for 5 billion years or so, when you return you should find that most of them have not just life, but social beings who are smart and produce culture. There are some caveats on this prediction, but the bottom line is that this combination of traits will be super useful in a wide variety of environments, so we should expect selection to favor it wherever possible (and it's usually possible).
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This is where things get interesting. A number of prominent scientists have recently used modern science to advocate for the very old idea that the universe itself exhibits a "complexity trend" over cosmic time (I won't go into it here, but "complexity" is not quite the right concept to use). Following the big bang, we initially just have boringly homogenous clouds of hydrogen and helium. But then stars form and fuse heavier elements and these elements combine to make planets. Complex biochemistry and ultimately life arises on the planets. So there's a story to tell where things naturally get more and more complex over time. Indeed, there seem to be some "major transitions" in the process where the amount of complex diversity increases exponentially following each successive transition - and certainly one such transition would be the initial appearance of life. Another transition, I want to argue, is the reason/sociality/culture triad. Together, these will naturally produce diversity at a rate many orders of magnitude more than "primitive" life, which is itself a major improvement over abiotic chemistry. Seen this way, the sociality/reason/culture triad is just the latest step in an inevitable cosmic unfolding, each step of which is marked by a dramatic increase in the amount of complexity and diversity in the universe.
But wait - there's more! Even more speculatively, I suspect all this might just provide the foundation for a new and truly universal (in some sense of that word) conception of ethics - one we would share with all other intelligent aliens. Think of it this way: anyone we would be able to debate ethics with must be rational. And they would have gotten to be rational via the same evolutionary process (leaving aside AI, which is a debate I haven't entered into yet), so they would be social and cultural just like us. But that opens the door to shared ethical concepts, since I take ethical principles to ultimately be nothing more than rules for producing stable social systems. Some ethical principles are bound to be necessary for any kind of lasting social system and thus will be shared by all intelligent beings in the universe. To take an obvious example, all rational aliens will have a prohibition against murder, since no social system could be stable if its people were free to kill each other whenever they wished. It may even be that service to the universe's unfolding diversity can be see as the purpose of all rational beings and their societies.
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It has not escaped my notice that there are theological overtones here and this makes me pretty uncomfortable. On the one hand, I'd rather not talk about the idea in religious terms, since this brings with it tons of weird conceptual baggage (like supernatural forces). On the other hand, what else should you call a theory which tries to explain the "purpose" of the universe and all the creatures in it - that sure sounds at least religion-adjacent. This is way outside my field of expertise, but I do try to talk in a very tentative way about how we might be able to have our cake and eat it too - that is, how it might be possible to have a "religion" which is also purely naturalistic in "The Smallest Step of Faith: A New Worldview for a Postmodern World."
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Q: How should we teach ethics, especially to those with little training (or interest) in philosophy?
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I lived this question for 15 years as a fellow of the Rutland Institute for Ethics, where part of my job was giving guest lectures on "The Ethics of X" (where X was whatever discipline had invited me) and teaching faculty in other disciplines how to introduce ethics into their own classes. My colleagues and I developed a unique approach to ethics education and even produced a basic ethics guide called "Getting it Right: A Toolbox Approach to Ethical Reasoning" that we have made available to educators everywhere. I used these ideas to run dozens of workshops for various audiences, give guest lectures (over 100) in almost every department at Clemson, and design the ethics and professionalism curriculum at the USC School of Medicine in Greenville.
Here's the answer: you teach ethics, not by giving detailed content on ethical theory (which is how most philosophers approach it), but rather by finding complex real life ethical questions and getting your students to discuss them Socratically. That's one of those ideas that is pretty simple in concept, but hard to implement in practice. First, there are a number of conceptual confusions that can get in the way of constructive debate - like the naturalistic fallacy and ethical relativism - so you have to find a simple, engaging way to teach these. Then, you have to get people to accept, deep in their heart of hearts, two counterintuitive ideas: 1) the goal is fostering a higher order thinking skill, not learning "the right answer" and 2) debating the questions in a Socratic fashion, even when this seems to reach no conclusion, is the best means to this end. We found that giving people hands-on experience running ethical discussions and troubleshooting the problems that inevitably arise is crucial. In "Ethics is not Rocket Science: How to Have Ethical Discussion in your Science Class" I lay out our basic approach and then in "Using Ethics Labs to Set a Framework for Ethical Discussion in an Undergraduate Science Course" we report on how the system actually worked in a Clemson genetics class.
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Q: What is the deal with creationism and what should we do about it?
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First, I need to be clear that I don't have a problem with all creationists, because people use that term in very different ways. If you are someone who thinks that God exists and created the universe, but don't specify any details of His workflow that conflict with evolutionary biology, then I have no quarrel with you. But if you want to say that more specific versions of creationism, like intelligent design theory, are on a par with evolution and should be taught in public schools, etc., then I vehemently disagree. What really annoys me is not the average person with creationist leanings, but the class of "evangelical creationist" who make it their life's work to convince people that evolution is wrong and creationism right. Of course, there is nothing with that goal in principle - if you are sincerely trying to get to the truth by carefully examining the evidence, etc., etc. The problem is that these guys all too often don't even try to be objective. Instead, they use whatever dirty tricks might convince non-experts rather than, I dunno, logic and stuff (for example, see this description of my frustrations with a radio "debate" I was snookered into here). What's more, unlike the average believer, they know their arguments are terrible and just don't care. In other words, they are in the propaganda business, not the education business, and this is something that must be fought (in creationism or anywhere else).
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In any event, anyone with my background as both an evolutionary biologist and philosopher gets dragged into these discussions all the time. I do think this is important work and wish my colleagues in philosophy and science 1) took it more seriously and 2) could deal with it more effectively. So in one sense I don't mind helping out. On the other hand, you don't get much academic credit for doing this, since most experts view it as "philosophy (or science) in first gear." And it can be seriously depressing to devastate a particular creationist argument only to see it return, zombie like, over and over and over again. As Darwin said in one of my favorite quotations: "Great is the power of steady misinterpretation."
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One piece I especially like is from a creationist conference I was invited to as one of the token "detractors" (all expenses paid - creationists don't lack healthy budgets). When I arrived, I discovered that I was to be given only 15 minutes to make my points, while the creationist speakers were all allowed an hour (just the sort of rhetorical dirty trick creationists love to employ). But while this was annoying at the time, it had the effect of forcing me to be very concise and clear. The director of the National Center for Science Education was in the audience and liked my talk so much that she published it. The result is "Can Intelligent Design Become Respectable?," a neat little piece that explains exactly what creationists need to do if they wish to be taken seriously by scientists. Heck, I even provided testable predictions creationists could pursue - so far, nobody has taken up the challenge, which you can interpret for yourself.
A much longer piece, "Appealing to Ignorance Behind the Cloak of Ambiguity," exposes the many flaws in the common "Intelligent Design" arguments and concludes they are not the sort of moves anyone who wants to get at the truth (rather than just convince people who don't know any better) should ever make. I am quite fond of this article for two reasons. First, it mentions all our kids and pets by name - my first bucket list accomplishment! Second, it generated the right kind of both friends and enemies: a creationist website awarded me the "snarky prize" for the nastiest response to creationism, while an article in Evolution (the lead journal in the field) cited it with the observation, "The most withering criticism of ID [intelligent design] theory comes not from scientists, but from philosophers." I mean, what more could you ask for?
I've also done debates with creationists from time to time, though you have to be extremely careful doing this as they have zero interest in playing fair. Of course, sometimes I can't resist and it doesn't always work out so well. In "I also Survived a Debate with a Creationist (with Reflections on the Perils of Democratic Information" I describe my horrible experiences on a talk show discussing creationism, and try to draw out some larger conclusions about how people approach public debate today and what this means for the future. Finally, there is "Foiling the Black Knight: How to Vanquish Creationist Knaves" where I realized my dream of publishing a serious article based on Monty Python's black knight sketch. In it, I give my scientist colleagues a hard time for the incredibly obtuse and ineffective way they tend to try to deal with creationists, which mirrors King Arthur's inability to defeat the black knight.
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Q: What exactly does it mean to describe a trait or a disease as "genetic"?
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I got interested in this question early in grad school, when we read a paper by Fred Gifford a Philosophy of Biology class. Gifford argued for a particular take on what a "genetic trait" is. At the time, I was really into "evo-devo," which emphasizes the synergies between evolution and development in biology. I was even doing empirical (gasp!) research on how genetic and environmental factors interact in complex ways (see "The Effects of Temperature and Daylength on the Rosa Polyphenism in the Buckeye Butterfly"). In any event, I thought Gifford's argument didn't give a realistic picture of biological complexity - in particular, it glossed over all the non-genetic elements that contribute to a trait. This was my first glimpse of my dissertation topic, though I didn't realize this immediately. Consider: a living organism can be viewed as a huge collection of causal factors, some genetic, some developmental, some environmental. Since many of them are important, even necessary, for the occurrence of a particular trait, how can you justify picking one out as the cause? Put another way, what justifies saying, "This factor (gene or whatever) is the explanation for this trait?" I eventually solved all this (well enough to fool my committee anyway) in my dissertation, "The Emperor's New Genes: The Role of the Genome in Development and Evolution" which took me from Aristotle's biology to Mackie's theory of causal explanation to systems biology. But before that magic happened, I got annoyed enough to write up a response for the class, which my advisor liked so much he recommended I try to get it published (may you all have such an advisor). This became the very first article I ever sent off for publication, eventually appearing as "The New Problem of Genetics: A Response to Gifford." I think it stands the test of time reasonably well, which is to say I only wince slightly at my naïveté when I read it now.
Around the same time, my advisor, Robert Brandon, led a research group discussing his use of a statistical technique called "screening-off" as a way of handling these kinds of complex causal situations. We eventually published a joint response to one of Brandon's critics, who had argued against his treatment of individual versus group selection: "Sober on Brandon on Screening-Off and the Levels of Selection." I went on to think about how this sort of statistical analysis might impact the genetic testing debate, which was just beginning to be a thing. I produced "Equivocal Notions of Accuracy and Genetic Screening of the General Population," which led to my being invited to submit a paper to the Journal of the American Medical Association discussing the implications for medical clinicians. I was super excited at the time since I was a newly minted Ph.D. and JAMA is a big deal. It's a good thing I did not know at the time that "Genetic Disease, Genetic Testing, and the Clinician" would turn out to be the most annoyingly difficult (and the shortest) paper I would ever write, as the editor was a huge pain to work with. But the pain lead to more good things as my work was noticed by some scholars in Denmark working on disease concepts and they paid my way to a Danish government conference in Copenhagen, which was awesome! I continued to work on this stuff for a while, eventually developing a full blown theory of genetic disease which I laid out in two papers: "Towards an Adequate Account of Genetic Disease" and "A Disease by any other Name: Musings on the Concept of a Genetic Disease." I won't even try to summarize my approach, since it's kinda technical and if I keep it brief here it will confuse - if you are interested, read the papers.
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In the final chapter of this story, I managed to convince a very famous philosopher, Kim Sterelny, that I was right to be skeptical about the explanatory power of genes. At the time, he was working with an Australian expert on platypuses and so the three of us collaborated on applying these ideas to the notion of a replicator (a standard conceptual tool in evolutionary biology), which resulted in "The Extended Replicator." We got playful, arguing that it's just as legitimate to say a platypus burrow explains the existence of a platypus as the other way around - we even claimed that to think otherwise was just rank "lifeism." When I showed it to Richard Dawkins, the super famous biologist, he immediately labeled it "perverse," which is still one of the proudest moments of my career! It's also easily the most cited piece I've ever done - I recommend young scholars work with famous people whenever possible...:)
Q: If genes don't explain traits all that well, can we say the "developmental system" does?
Early on, I got involved with a group of "process structuralists" who really wanted to argue that there were "generative laws" which manifest themselves through the interplay of the organism and its environment in development. These were supposed to be true laws of nature, holding out the promise of putting biology on a par with physics. It was a weird mix of Kantian rationalism and developmental biology that drew me in because 1) It was radical and young people love radical ideas, 2) there was a lot of overlap between some of what they said and my early work and 3) they had a pleasant habit of holding conferences in exotic locales. I flirted with them for a while (and went to some spiffy conferences), but eventually moved on to other things as their ideas were just too vague and unspecific to have much impact on real biologists, which has always been my measure of whether what I am doing is legit. I summarized my final take on the movement in "Neo-Rationalism vs. Neo-Darwinism: Integrating Development and Evolution." It should be noted that some of those in this group went on to create the much more reasonable "developmental systems theory," which has been pretty influential in philosophy of biology, so it could be argued that I jumped ship prematurely. But to my mind they still haven't solved some of the problems I pointed out way back then, so no regrets.
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FINI (for now)
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