¹ Liao, Matthew S., Sandberg, Anders and Roache, Rebecca, ‘Human engineering and climate change’, Ethics, Policy & Environment 15.2 (2012), 206–221 CrossRefGoogle Scholar.

² Ingmar Persson and Julian Savulescu, Unfit for the future: The need for moral enhancement (New York: Oxford University Press, 2012), 2. Persson and Savulescu are also concerned with enhancing our moral motivation so as to allow for changes in our mode of life that will allow us to effectively prevent terrorism.

³ John Harris, ‘Enhancements are a Moral Obligation’, in Julian Savulescu and Nick Bostrom (eds), Human Enhancement (Oxford: Oxford University Press, 2009), 134.

⁴ Francis Kamm, ‘What Is and Is Not Wrong With Enhancement?’, in Julian Savulescu and Nick Bostrom (eds), Human Enhancement (Oxford: Oxford University Press, 2009), n.13, 103.

⁵ These are Kamm's examples.

⁶ Op. cit. note 3, 134.

⁷ Lewens, Tim, ‘Human Nature: The very idea’, Philosophy & Technology 25.4 (2012), 460CrossRefGoogle Scholar.

⁸ Our defence of the place of the concept of nature in debates about enhancement, then, is different from those like Kass, Leon, ‘Ageless bodies, happy souls’, The New Atlantis 1 (2003), 9–28 Google Scholar; Francis Fukayama, Our posthuman future: Consequences of the biotechnology revolution (New York: Picador, 2002); and Michael J. Sandel, The case against perfection (Cambridge MA: Harvard University Press, 2009) who deploy particular (and contentious) conceptions of the content of human nature and its origin in order to caution against particular kinds of enhancement ( Hauskeller, Michael, ‘Human enhancement and the giftedness of life’, Philosophical Papers 40 (2011), 55–79 CrossRefGoogle Scholar  offers a detailed defense of Sandel's view). For reasons that will emerge below, we do not see our position as lending support to the anti-enhancement camps. If anything, our view provides (modest) support for the enhancement camp.

⁹ Allen E. Buchanan, Beyond Humanity? The Ethics of Enhancement (New York: Oxford University Press, 2011).

¹⁰ In what follows we focus on Buchanan's position, though we believe that his central points are supported by a large number of contemporary philosophers. We are using the terms ‘trait’ and ‘characteristic’ interchangeably.

¹¹ Op cit. note 9, 137.

¹² Ibid., 123–124.

¹³ Ibid., 118.

¹⁴ A clear, concise version of this kind of account of human nature can be found in Edouard Machery, ‘A Plea for Human Nature’, in Arguing about human nature: contemporary debates, Stephen M. Downes and Edouard Machery (eds) (New York: Routledge, 2013).

¹⁵ The discussion in this section is heavily indebted to Michael Thompson, ‘Apprehending Human Form’, Royal Institute of Philosophy Supplement 54 (2004): 47–74. In section 4, we turn directly to Thompson's view, and our debt is even more clear.

¹⁶ Møller, Anders Pape et al. ‘Chernobyl birds have smaller brains’, PLoS One 6.2 (2011): e16862CrossRefGoogle ScholarPubMed.

¹⁷ See Michael Thompson, Life and Action: Elementary Structures of Practice and Practical Thought (Cambridge MA: Harvard University Press 2008), chapter four.

¹⁸ Op. cit. note 9, 118.

¹⁹ What of Buchanan's third component of his conception of human nature? We consider it below, on page 14.

²⁰ Op. cit. note 17.

²¹ There is also a third, crucial claim which connects the representation of life to the evaluation of it. We discuss this in detail in section 5.

²² Op. cit. note 17, 73.

²³ At this point, one might worry that there is a deep problem for this view. For, on the one hand, we cannot understand any particular behavior or activity as the kind of thing it is without situating it in the context of the thing's life-form. But, on the other hand, we cannot come to apprehend a thing's life form without first observing particularly behaviors and activities (as particular behaviors and activities). Clearly, apprehending life-forms is not an a priori, armchair exercise; it requires actual fieldwork! But then it looks like, contra what we have been arguing here, any particular life-form conception must come after at least some preliminary statistical conception of the thing under observation (‘Hey look! All four of them have tail-like appendages!’). The solution to this problem is to differentiate between two claims: (a) the conception of a particular life-form that we settle on comes after, and is based-on, particular observations of individuals of the life-form, and (b) particular observations of individual organisms are prior to forming any conception of the thing's life-form. The advocate of the life-form conception will grant (a), but deny (b). Of course our conception of the life-form ‘bobcat’ comes about from observing bobcats. It would be absurd to deny that. But this is consistent with thinking that even the initial observations of particular bobcats brought with them the idea of a form of life instantiated by this kind of thing, and that it is this idea – however implicit – that is required for the identification (or perhaps, initially, misidentification) of particular behaviors as instances of reproduction, or eating, or defectation etc. As Michael Thompson (Op. cit. note 15, 52) helpfully puts it in his discussion of jellyfish:

This resolution to the problem should make clear something else about the view we are defending, namely that life-forms are not unchanging essences or hidden ‘micro-structures’.  Life-forms themselves, and our conception of them, will change over time ‘as they are affected by selection, mutation, drift and so forth’ (Op. cit. note 7, 461).

²⁴ Op. cit. note 9, 136–137.

²⁵ This formulation of the neo-Aristotelian position highlights why a recent criticism from Lewens misses the mark. Lewens claims that at best Thompson and Foot offer support for the view, established by a bevy of social science research, that people are ‘intuitive essentialists’ (Op. cit. note 7, 468). As he puts it, Foot and Thompson ‘have shown only that people are intuitive Aristotelians, without showing that Aristotelianism is a position we should adopt’ and that, ‘the onus is on the likes of Foot and Thompson not merely to show that much discourse seems committed to normative essences, but that there really are such essences’ (Op. cit. note 7, 469). The problem, as Lewens sees it, is that they cannot meet this burden because, ‘there's no justification in biological reality for that conception [of a species’ nature]’ (Op. cit. note 7, 469).

However, if what we've said is right, then Lewens is mistaken. To begin, Thompson and Foot are not just helping themselves to ‘intuitive essentialism’ without argument. Rather, Thompson argues (convincingly we think) that any of our thinking about living things as living cannot dispense with life-form judgments. Indeed, as we hope to have shown, even the statistical conception of species that Lewens’ favors cannot do without the Aristotelian conception of life-form he wants to jettison. If Thompson's arguments about life forms are correct, then we cannot so much as bring ‘biological reality’ into view without relying on life-form judgments; life-form thought is a precondition for there to be a subject matter of biological investigation.

The burden, then, is on Lewens to show where the arguments for life-form thought – including those given here – go wrong. Oddly, Lewens never takes up this burden. In fact, he acknowledges this at one point, saying  ‘what follows is not intended as a refutation of their [Thompson's and Foot's] work, because I will not be addressing the most important parts of their case’ (Op. cit. note 7, 467). In another essay on Foot, Lewens also fails to address the core arguments we have outlined here. See Lewens, Tim, ‘Foot Note’, Analysis 70 (2010), 468–473 CrossRefGoogle Scholar.

²⁶ Op. cit. note 17, 81 (emphasis added). Philippa Foot, Natural Goodness (Oxford: Oxford University Press, 2001) uses the terms ‘natural goodness’ and ‘natural defect’ to describe the sort of goodness as or badness as that arises from a comparison between a) the representation of a life form, (e.g. ‘the tiger has four legs’) and b) the representation of an individual bearer of the form (e.g. ‘this tiger has three legs’). Foot also calls this ‘intrinsic’ or ‘autonomous’ goodness in living things, since it is a kind of goodness that is not derived from our purposes for living things. When we speak about goodness as, or goodness in, it is this sort of intrinsic goodness that we have in mind.

We can now understand better why traits characterized as defects or distortions cannot belong to the representation of the life form: the life form itself is the criterion for determining what counts as defect or distortion in individual members of the kind. We judge that a certain functioning of the human heart is defective by comparing individual hearts to ‘the human heart’, i.e. to a conception of the properly functioning heart, as defined by the natural history of human beings. It is thus not an ad hoc maneuver, or misplaced optimism, to say that defects are not part of human form. Rather it follows from the very judgment that something is defective, i.e. a lack of goodness as human beings. And this makes even clearer the difference between the statistical concept of human nature and the human form view. On the statistical concept, it makes perfect sense to say ‘to err is human’. On the human form view, it is closer to the truth (though less poetic) to say ‘what counts as “erring” is determined by “the human”’. We can, of course, affirm both of these senses of human nature without contradiction, so long as we keep straight which sense of human nature we have in mind.

²⁷ Of course, Kamm might have had in mind something like the statistical conception of ‘the human’ in mind when she wrote this. But if that's the case, then the point we made above (14) applies here: the statistical conception of human nature supports the Inert View_nature, not the Inert View_form.

²⁸ In some cases, the prima facie reason will also be a pro tanto reason. In other cases, it won't. We might think that it is good for the killer to get a new axe, without thinking that that gives anyone any reason to give the killer an axe. But this does not mean that there is no conceptual connection between X being good for Y and there being a reason to do X for Y. It just means that in some cases, the connection is undermined (while in others it is outweighed). See Garrett Cullity, The Moral Demands of Affluence (Oxford: Clarendon Press, 2004), 17–18.

²⁹ Richard Kraut, What Is Good and Why: The Ethics of Well-Being (Cambridge MA: Harvard University Press, 2007), 131.

³⁰ A similar example involving a snail is discussed in Copp, David and Sobel, David, ‘Morality and Virtue: An Assessment of Some Recent Work in Virtue Ethics’, Ethics 114 (2004), 514–554 CrossRefGoogle Scholar.

³¹ We have adapted this example from Christine Korsgaard, ‘The Relational Character of the Good’ in Oxford Studies in Metaethics Vol. 8, Russ Shafer-Landau ed. (Oxford: Oxford University Press, 2013).

³² But can't we ask of this individual whether it would be better off as a tiger or a phiger? Our answer is the same: if the change is radical enough, then we'll deny that we're dealing with the same individual. If, on the other hand, we have a case where the very same individual persists through the change that is because its form has remained sufficiently stable. Of course, what counts as a radical enough change is a big question. A general and illuminating answer may not be available, and in any case our point does not require one.

³³ Cf. Foot Op cit. note 26, 30–33.

³⁴ Indeed, many such interventions might not be ‘enhancements’, strictly speaking, but therapeutic interventions to restore or preserve an aspect of proper functioning that commonly goes awry.

³⁵ This is a necessary, not sufficient, condition.

³⁶ Again, any particular argument to this effect requires bringing a substantive conception of human form to the table. See above, on page 3.

³⁷ See above n. 32.

³⁸ Thanks to Sarah Jansen, Richard Kim, Charles Taliaferro and an anonymous referee for helpful feedback on earlier drafts.