[This is a slightly expanded version of a talk I gave at the SIENNA workshop on the ethics of human enhancement in Uppsala, Sweden on the 13th June 2019. The talk was intended to be a provocation rather than a comprehensively reasoned argument.]
I've been asked to say a few words about the challenges that emerging enhancement technologies might pose for how we define human nature (with a nod towards how this might also interact with the 'dual use' nature of technology). I didn't say this to the organisers when they asked me, but this is a difficult topic for me to talk about. That's because I am a sceptic of human nature. I tend to agree with Allen Buchanan (2009; 2011) that discussions of 'human nature' in the enhancement debate tend to obscure more than they clarify. This is because the term 'human nature' usually functions as a proxy for something else that people care about. My feeling is that people should talk about that something else instead, and not about human nature.
That said I'm clearly in a minority in taking this sceptical view. People are hungry for discussions of human nature. The library shelves groan under the weight of scholarly volumes dedicated to the topic. Just to illustrate, there was a book I read many years ago as a student by Leslie Stevenson called Seven Theories of Human Nature. It was first published in 1987. In 2017, they published the seventh edition of the book, now titled Thirteen Theories of Human Nature - apparently the number of theories of human nature had doubled in the intervening 30 years. At that rate of growth, the number of theories of human nature will exceed the total number of humans in just over 900 years. Clearly people are obsessed with this topic.
What is it that obsesses them? Obviously, I can't do justice to the diversity of thinking on this matter -- I'm just setting up a conversation -- but I can at least help to structure that conversation by considering three senses in which people use the term 'human nature' and by explaining what I find problematic and interesting about them.
The first sense is as a descriptive-explanatory theory, i.e. as a theory that describes some fundamental truth(s) about what it is to be a human being. The classic descriptive theories of human nature are essentialist in nature. They try to identify the characteristics that are both necessary and sufficient for belonging to the kind 'human being', They do this usually by engaging in human exceptionalism: i.e. by focusing on characteristics that distinguish members of human kind from other animals. Typical examples of such characteristics include things like the capacity for self-consciousness, altruism, language, laughter, art, complex tool use and so on.
These essentialist theories are scientifically dubious. In this regard I find myself swayed by an old argument by the philosopher David Hull to the effect that modern evolutionary biology undermines essentialistic theories of human nature. This is because modern evolutionary biology endorses the view that world is filled with genetically varying individuals that occasionally form stable reproductive populations that we call 'species', but these 'species' are temporary, and at least partially, linguistic facts. As he put it:
[I]t is simply not true that all organisms that belong to Homo Sapiens as a biological species are essentially the same… periodically a biological species might be characterised by one or more characters which are both universally distributed among and limited to the organisms belonging to that species, but such states of affairs are temporary, contingent and relatively rare.
Even if you don't buy that argument, there are two other fatal flaws with the essentialist theory. Whatever characteristic you pick as being distinctive of humans (self-consciousness, altruism etc) you can (a) find animals that share primitive or proto-versions of those traits (with perhaps the exception of true language) and, more importantly, (b) find individuals (or groups of individuals) that we would like to call 'human' that lack them, either due to disability or disease or some other factor.
These problems with the essentialist theory have led some scientists and philosophers to endorse non-essentialist theories of human nature. These theories do not pretend to identify distinctively human characteristics but, rather, try to identify characteristics that tend (statistically) to be shared by humans in virtue of their evolutionary and developmental origins. Edouard Machery, for example, has defended a 'nomological' theory of human nature that focuses on traits that have their origins in our shared evolutionary history. Similarly, Michael Tomasello, in his recent trilogy A Natural History of Human Thinking, A Natural History of Human Morality, and Becoming Human: A Theory of Ontogeny, has defended a theory of human nature that focuses on characteristics that emerge from our shared evolution and ontogenetic development (although I find that Tomasello leans too far in favour of the human exceptionalism that is typical of essentialist theories of human nature). Related to this, it is also worth noting that some people argue that we should move away from theories of human nature that expect it to be a stable and unique 'thing' and should, instead, favour theories that view it as a 'process'. This is because an individual human being is not a stable thing but is, rather, a process that develops and changes over time (proponents of this view include John Dupré and Paul Griffiths).
These non-essentialist theories strike me as being much more plausible, but after reading about them I tend to wonder how useful they are, even as scientific theories. The problem is that they all tend to allow for a lot of individual and cultural variation in the traits that are supposed to define our natures. Furthermore, I often get the sense that their proponents pick and choose characteristics that they think are important and interesting and use those to define what it means to be human. In this sense, I worry that proponents of these theories are like dog breeders that measure each individual dog relative to an 'ideal breed type', which as best I can tell are arbitrary constructions. In other words, just as there is no ideal dalmation or poodle; so too is there no ideal human. The problem is that even these non-essentialist theories of human nature tend to assume that there is.
This brings me to the second sense in which people use the term 'human nature', namely: as a normative theory of what is good/bad (and permissible/impermissible) for 'creatures like us'. This normative approach to human nature is probably the approach that we are most interested in here today. We are all presumably familiar with the way in which normative theories of human nature get weaponised in debates about the ethics of enhancement. Some people claim that enhancement is against human nature and so ought to be stopped; some people claim that it is expressing our most human traits and so ought to be celebrated. Neither side persuades the other.
Normative theories of human nature could be thought of as being entirely distinct from descriptive theories of human nature. If they were, I would probably find them unobjectionable, but that's only because they would then be indistinguishable from theories of human well-being and flourishing (which, though contested, do, provide some genuine normative guidance with respect to enhancement). The problem is that many people try to ground their normative theories of human nature in descriptive theories, presumably to give them some extra normative 'oomph'. Suffice to say, I find this practice highly dubious because I find those grounding theories highly dubious. There is the same 'pic-and-mix' mentality at play: people select characteristics they happen to like and then reify them into this descriptive-normative theory of what it is to flourish as a human being.
A clear example of this mentality in action, at least based on my reading, is the theory of human nature that the conservative philosopher Roger Scruton puts forward in his 2017 book On Human Nature (Princeton University Press, 2017). Scruton, who has always been a controversial figure, is much-maligned recently due to his apparent sympathy for the right-wing governments in Poland and Hungary and the fact that he has been favoured by both governments. I mention this not to poison the well but because I expect people reading this would find it odd if I didn't make some allusion to this ongoing controversy. Anyway, in the book Scruton argues against reductionist/scientific theories of human nature and in favour of an emergentist/Kantian theory. Roughly, he claims that what is distinctive about humanity is that we understand ourselves and our fellow humans to be moral agents, who possess a unique first-person perspective on the world, and are capable of grasping and acting for moral reasons. A couple of quotes will give you a flavour of his approach:
I want to take seriously the suggestion that we must be understood through another order of explanation than that offered by genetics and that we belong to a kind that is not defined by the biological organization of its members.
We are animals certainly; but we are also incarnate persons, with cognitive capacities that are not shared by other animals and which endow us with an entirely distinctive emotional life--one dependent on self-conscious thought processes that are unique to our kind.
We are the kind of thing that relates to members of its kind through interpersonal attitudes and through self-prediction of its own mental states.
I don't want to dismiss these thoughts entirely. Clearly, there is a sense in which it is true that this mode of self-understanding and interpersonal relationality is central to the human experience1, but there is also a sense in these are the properties that Scruton would like to associate with what it means to be human. Shining the spotlight on these characteristics obscures the fact that some humans don't express or exemplify these properties in the form that Scruton imagines, and that most (all?) humans are more than just these properties.
Despite my scepticism of theories like this, I do think that (non-essentialist) descriptive theories of human nature can provide some important normative heuristics to those of us interested in the enhancement project. They might help us to identify practical limits to what it is possible to change about most humans without doing harm. This might be useful when it comes to setting policies at a population level (while acknowledging exceptions at an individual level). Nick Bostrom and Anders Sandberg discussed this point several years ago in their paper 'The Wisdom of Nature: An Evolutionary Heuristic for Enhancement'. They accepted that there was some room for a form of Burkean conservatism in the enhancement debate: the human body was a complex, evolved system and we should be cautious about tinkering with it too much and too quickly -- though they certainly didn't rule out that tinkering entirely.
That said, one problem with the enhancement project is that -- at its most speculative limits -- it threatens to entirely destabilise any descriptive theory of human nature. What I mean here is that if we achieve near perfect technological control over every aspect of our biology, then there will be no practical constraints on what we can do to ourselves and hence nothing to provide even heuristic normative guidance to our policy-making. It will be entirely up to us to decide what form of life we want live. Some people find this idea deeply disturbing. It is almost like they want to cling to a mythical form of human nature in order to avoid the burden of choosing what kind of life they want to live for themselves (and, yes, there is something redolent of Sartrean existentialism in this but I don't have time to explore it further in these remarks).
This brings me to the final sense in which people talk about 'human nature', namely: as a catch-all explanation (and maybe excuse) for the 'darker' things we do. This is human nature as an 'anti-normative' theory. What I have in mind here is people who say things like 'it is in our nature to be violent' or 'it is in our nature to be jealous/envious'. These sentences, which are common, all seem to be wistful lamentations about the dark side of what it means to be human. They are designed to caution us against ourselves.
This third sense of the term suffers from the same basic flaws as the second sense of the term. To the extent that it is a theory of human evil or human badness it is relatively unobjectionable; to the extent that it tries to ground itself in a descriptive-essentialist theory, it has some problems. That said, this third sense of human nature has obvious implications for debates about the dual-use nature of technology. If humans tend (statistically) to have a dark side, and if it is relatively fixed and stable, then it will pose regulatory and strategic challenges when it comes to the development of technologies that can be used for good or ill. I think one of best recent expositors of these challenges is Phil Torres. Phil has written some thought-provoking and terrifying essays about the threat that 'omnicidal' or 'apocalyptic' agents pose to the future of humanity (I interviewed him about his work here). These are human beings whose dark side is, for whatever reason, turned up to eleven. Phil's point (echoed by Nick Bostrom in his paper 'The Vulnerable World Hypothesis' and Ingmar Persson and Julian Savulescu in their series of books and papers on the 'unfit for the future' idea) is that as powerful technologies become more widely dispersed, the probability that one of these apocalyptic agents will misuse them starts to get unnervingly high.
Unless we can do something to identify, reform and/or neutralise these individuals, then human nature (whatever we take it to be) doesn't have much of a future. What is interesting to me is that Phil and the others who raise this point often suggest technological solutions to the problem. The idea seems to be that powerful and widely dispersed technologies, when combined with the dark side of human nature, could lead to our doom. The problem is that we cannot (or are highly unlikely) to stop the development and dispersal of powerful technologies. Therefore, we need some technological fix that will either (a) identify and neutralise potentially threatening humans (Phil's suggestion) or (b) correct for the dark side of humanity using some kind of moral enhancement technology (Persson and Savulescu's suggestion). As best I can tell, all proponents of this argument admit that their technological solutions are highly speculative and unlikely to work in practice. They are, in a sense, a 'hail Mary pass', a last desperate attempt to stop humanity from sliding over the cliff. But if that's the case, I'm not sure that anti-technological solutions (i.e. solutions focussed on preventing the development and dispersal of powerful technologies) can be dismissed so quickly2.
Either way, it seems that if you believe that human nature is dark and relatively fixed, you should be very worried about the future.