When philosophers of biology write about human nature, their goal is typically to see what sense can be made of the very idea that there might be a human nature, prior to the provision of details about what the exact features of such a nature might be. The great majority of the work done in this area over the past forty years or so falls into one of two genres. First, there are positive proposals for naturalistic analyses. They all aim to identify human nature with some set of biologically or psychologically salient patterns, processes, or properties. Second, there are equally naturalistic expressions of scepticism about human nature; ‘naturalistic’, because this type of work proposes that an up-to-date understanding of evolution and development leaves no room for any notion of human nature.

To give three examples of work in the first genre, Edouard Machery ([2008], p. 323) has proposed that human nature is the set of properties that ‘humans tend to possess as a result of the evolution of their species’. Machery’s idea is that, regardless of the importance one might attach to it, a trait cannot count as an element of human nature if it is possessed by only a minority of humans, nor can it count as an element of human nature if it has become widespread purely because of learning from others. Cecilia Heyes ([2018]) has defended something similar. She loosens Machery’s analysis, by allowing that learning from others (so long as it is of the right sort) can ground the appearance of some elements of human nature. She also tightens it by insisting that only mechanisms that ‘underlie the manifestation of species-typical cognitive and behavioural regularities’ qualify ([2018], p. 87); in other words, for Heyes human nature cannot be identified with simple regularities in behaviour and cognition, only with underlying mechanisms that explain these regularities. Finally, while Grant Ramsey ([2023]) sees good reason to avoid an account that triages traits into those that are and are not part of human nature, his analysis is of a straightforward naturalistic kind all the same. He proposes that ‘human nature’ is the name for the collection of patterns shown in developmental pathways across human lives.

Beginning with David Hull ([1986]), the second sceptical genre of work often reacts to accounts like the ones just mentioned by saying that the distinctions they rely on cannot be drawn; or perhaps that they fail to take account of the complexities of evolution and development; or that they reify distinctions (between nature and culture, for example) that investigators would be better off giving up on; or that the idea of human nature is one that systematically misleads scientific researchers (for example, Lewens [2012]; Laland and Brown [2018]; Sterelny [2018]).

In dividing work into these two genres, I do not mean to imply that all philosophers neatly fit the taxonomy proposed. Maria Kronfeldner ([2018]), for example, begins her very fine book on the subject by attending to the uses of the human nature concept—including its many adverse political uses—before asking what to do about it. But Kronfeldner ultimately leans towards eliminating the human nature concept, and in this respect she falls in with the sceptics. It is refreshing, then, to read two different books that both defy these dominant genres.

The pictures of human nature offered by Mameli and Nathan have much in common. Both see problems with many of the specific positive proposals made by philosophers for how to understand what human nature is, but neither is an eliminativist about the notion. Both pay considerable attention to the roles of human nature concepts in political debate, including debates about gender and racial equality. Finally, both rest their views about human nature on accounts of what the concept is fundamentally for, and neither author sees that role as a simple one of picking out some easily circumscribed set of biological facts. For Nathan, human nature is one of several concepts that gesture to a significant subject matter for investigation, without being susceptible to any more reductive analysis. For Mameli, human nature acts as a kind of intermediary—he calls it a ‘channel of communication’—that serves as a go-between linking descriptive knowledge of human traits with various ambitions for human living or, as he prefers to call it, praxis.

Having said a little about what the books have in common, let me make some remarks about each in turn, starting with Nathan. The overall strategy of his book begins with an effort to show that a whole series of potential proposals for naturalistic analyses of human nature fails. Nathan considers and rejects (among several other suggestions) the idea that ‘human nature’ names those traits that are innate, or those traits that are genetically determined, or those traits that would appear in a ‘field guide’ to our species. In these respects, Nathan is following in the footsteps of human nature sceptics. But Nathan does not embrace any form of eliminativism about human nature. What is more, this is not merely on the grounds that it is implausible that the philosopher might succeed in getting people to stop using an entrenched term like ‘human nature’. Nathan’s argument is more principled than this. He takes the view that a series of significant ethical and political debates—in particular, debates about racial and gender equality, and about the rights and wrongs of human enhancement—cannot get going without some underlying notion of human nature. So, while the first half of the book features a series of chapters that find faults in positive naturalistic proposals for what human nature is, the second half instead urges that various vital debates simply cannot take place in the absence of a notion of human nature. In the final chapter of the book, Nathan offers a principled resolution of this standoff: his view is that a proper understanding of the function of the human nature concept shows that we should not expect any naturalistic analysis of that concept to succeed, while also preserving a valuable role it.

Human nature is what Nathan (following Foucault) calls an ‘epistemological indicator’, and because of this it resists definition. Indicator concepts, ‘delineate a set of explananda without any pretense of explaining them’ (p. 305). Very roughly speaking, the reason for this unanalysability turns on aspects of supervenience. On Nathan’s view, whenever a concept picks out a property that supervenes on lower-level properties, one will find that informative claims can be made about the higher-level property by appealing to those lower-level properties. But those claims will not consist in anything like an analysis, definition, or general account of the higher-level property. Nathan puts it like this:

Human na­ture is not merely a multiply realizable and miscellaneous collection of traits. It is further an overarching organizing principle, a mode of classification, an epistemological indicator, as Foucault dubs it. We can reduce human nature to more precise concepts. By doing so, we gain the opportunity of explaining the phenomena in question. At the same time, we also lose something significant: we end up altering its defining feature, that is, its intrinsic purpose and generality. In this respect, by analyzing human nature we thereby dissolve it. (p. 317)

I will say something about this positive proposal in a moment; first, let me focus on the bulk of the book. It has its origins in an introductory survey course, and perhaps because of this Nathan moves quickly across a very broad range of topics: there are discussions of innateness, of genetic causation, of debates about race and gender, of transhumanism, and many other subjects. Some of the argumentative moves he makes would doubtless provoke a lively class discussion, but they strike me as too quick to convince a solitary reader. For example, in the concluding chapter Nathan reminds his audience of one of the results of an earlier discussion:

The absurdity of eschewing the notion of human nature from normative discussions emerged with the most clarity while examining the issue of transhumanism. Should we be con­cerned about enhancing our nature? Should we be excited? These questions are plainly meaningless without adopting a preliminary firm stance on what we take our nature to be. (p. 326)

True enough, the question of whether human nature should be modified presupposes that human nature is a respectable subject for discussion. But one can consistently take the view that human nature is not a respectable notion, while also engaging in debate about transhumanism. It is possible, for example, to raise a series of questions about the risks and benefits of attempting to modify attention span, or empathy, or perceptual capacities, or cardiovascular fitness, or whatever the focal trait may be, in either a handful of humans or many of them. If, instead of asking these focused questions, one simply asks whether it is wise or unwise to modify human nature, one thereby risks effacing a series of details about exactly how these changes to individual humans are to take place. Is the idea that national health services will intervene in the genomes of the next generation’s germ-cells; is the proposal that a state broadcaster will lay on more instructive children’s television programming; or is the idea that tax-incentives will be offered to companies that reduce the amount of sugar in drinks? Indeed, one might think that a more focused debate, which specifies which humans are to be modified and how, is more productive than an unspecified effort to assess augmentations of human nature. The eschewal of human nature brings with it a rejection of the terms of some debates, but this may be a good thing.

Let me also consider potential responses to Nathan’s case against specific proposals for how to understand human nature. He remarks that ‘it remains questionable whether field guides spell out a thick notion of human nature robust enough to ground sociopolitical and other normative theories’ (p. 296). Here, Nathan is alluding to a conception of human nature that seems particularly undemanding, and which has been endorsed by Machery ([2008]) and Peter Godfrey-Smith ([2014]). This is the thought that a delineation of human nature is equivalent to the sort of diagnostic information about members of other species that one sees in a field-guide.

Nathan is right that a field-guide is the wrong way to think about what human nature is; indeed, it’s the wrong way to think about the nature of any species. A field-guide tells the user how to assign an individual to its species, and for that reason such guides focus only on easily observable traits and on traits that are diagnostic of the species in question. This is not the same as listing traits that have fundamental significance for the species in question. For example, suppose one thinks that the ability to learn from others is an important aspect of human nature. (It is, after all, something humans are extremely good at, and it is also something that has had huge impact on human life because of the ways that it enables technological innovation, scientific advancement, and so forth.) It is hard to observe this capacity while out ‘in the field’, and this is also a capacity that is possessed (although perhaps not to the same degree) by many other species. So it would be of little use in a diagnostic field guide.

But while the field-guide conception of human nature is wrong, it is much less clear what is wrong with a rough-and-ready account of human nature as that collection of traits possessed by most humans. Would anything be lacking in a simple account of human nature that describes what most humans are like, most of the time? Nathan gestures to a reply:

[…] the very insinuation that we can have meaningful discussions of the marginalization of certain groups, and re­lated reflections on emancipation and social justice, without some underlying conception of human nature and human rights is a chimera. We need some notion of shared humanity in order to pursue racial justice, gender equality, and other pressing items in our sociopolitical agenda. (p. 325)

An account that tells us what most humans are like does not serve this agenda, because it falls short of articulating something shared by literally all humans. However, Nathan’s own approach to human nature as an epistemic indicator also does not guarantee that whatever human nature is, it has to be something that all humans possess; nor does it contain any account of how something that is thin enough to be possessed by all members of Homo sapiens might also be thick enough to ground substantive reflections on social justice. Nathan may be right that an account of human nature can help with these issues, but the opposite, more sceptical conjecture also remains in play; namely, that prospects for a substantive account of human nature as something to be found in all individuals are problematic enough that one is better off seeking a foundation for social justice elsewhere.

It is also unclear exactly how Nathan’s approach to human nature as an epistemic indicator shows why it ‘eludes strict defini­tion’ (p. 320). One of the concepts he reaches for when explaining his general stance on epistemic indicators is evolutionary fitness. Nathan’s thought is that as one starts to articulate specific ecological events within the lives of individual organisms—this moth was eaten by a bird, this moth remained camouflaged—the higher-level concept of fitness as applied to trait types in a population drops out of explanatory descriptions. But while this does indeed suggest that no general definition of fitness will be forthcoming in terms of detailed ecological relations, it does not by itself mean that there is no illuminating definition of fitness at all. In fact, Nathan alludes to one proposal, namely, that fitness captures ‘the propensity of organisms to survive and reproduce’ (p. 310). A little later he generalizes his approach to epistemic indicators by reflecting on supervenience:

[…] every time we have a property S that supervenes on physical properties P—in the sense that any change in S will necessitate a cor­responding change in P but a change in P does not entail a change in S—we can always redescribe S at the level of P. The point is per­fectly general. It literally spans the entire board, from mundane dis­position ascriptions like the fragility of glass or the solubility of salt to explanations in the special sciences. (p. 311)

But once again, this does not show that ‘fragility’ or ‘solubility’ cannot be defined in an informative way, even if it shows that they cannot be defined by identifying a single supervenience base. A definition of solubility as the disposition to dissolve when placed in a suitable relevant liquid remains in play; and one might wonder whether some relevant high-level definition of human nature remains in play, too, in spite of the function of the term as an indicator.

In laying out these critical comments, I do not mean to suggest that Nathan’s approach cannot work. On my reading, Mameli’s excellent short book suggests some ways in which one might bolster versions of Nathan’s arguments. Mameli, like Nathan, aims to vindicate human nature while showing due deference to the many sceptical arguments levelled against specific philosophical analyses of what human nature is. Like Nathan, Mameli also broadens the scope of discussion well beyond the biological subject matter often discussed by philosophers working in this area: he, too, looks at issues of racial and gender equality, and he also casts his net over the history of appeals to human nature in political thought.

Mameli differs from Nathan in that he offers a definition, of sorts, of human nature. Even so, it is disarmingly simple: ‘Arguably, a general way of thinking about human nature is a general way of thinking about what we fundamentally are, or at least some aspects of it’ (p. 62). To describe human nature is simply to give an account of fundamental truths about humans. Perhaps the most significant idea in Mameli’s book is to pinpoint the function of this type of description as a ‘channel of communication’ between, on the one hand, descriptive results from the sciences (but potentially from the arts and humanities, too) about what humans are like and, on the other hand, important social and political goals humans may have that set directions for change. So, although Mameli doesn’t quite put it this way, traits are ‘fundamental’ to the extent that learning about them is potentially relevant to informing such large-scale projects.

For Mameli, the upshot is that human nature is (as part of its basic function) inevitably relevant to political concerns. Nonetheless, an account of human nature that reflected political concerns in an overly direct way—for example, an account that says ‘S is an aspect of human nature if and only if S is part of an ideal way for a human to be’—would fall too far on the side of a simple articulation of political ambitions to serve as a channel between what is known about humans and normative goals. He summarizes the view thus:

Human Nature encompasses all our important phenotypic traits and differences […] Is this way of thinking about human nature too permissive? It is only as permissive as the criteria we choose to identify those ‘corporeal and mental endowments’ that are important (or fundamental) in the context of scientific theorizing about humans or in the context of conversations about human futures. (p. 104)

For Mameli, this means that claims about human nature have the potential to take surprising forms, because there are cogent suggestions for significant truths about humans that need not be restricted to claims about statistically typical individual psychologies. For Engels, for example, it was important to draw attention to the ways that our ability to monitor and reflect on the consequences of action amplifies humans’ forms of niche construction compared with those of other species. This feature of collective niche-construction thereby becomes a central aspect of human nature for Engels.

This all helps to explain why Mameli spends a good amount of time reviewing the diverse images of human nature offered by prominent philosophers, theologians, and others over many centuries. While Mameli’s book is admirably short, it contains lovely vignettes of the views of Aristotle, Augustine, Hobbes, Rousseau, Marx (Mameli’s fondness of Marx is palpable), Engels, and others. These illustrations help to vindicate Mameli’s image of human nature as a channel of communication, and one that has, as a matter of fact, carried many different messages. They thereby help to undermine any thought, based on received use, that an account of human nature does not merit the name unless human nature is clearly distinguished from human culture; or that human nature must pick out unchanging features of humans; or that human nature must pick out properties that are widely shared, as opposed to properties that may be manifested only in significant fractions of the population. Mameli’s examples also aim to show the efficacy of this channel of communication: As he sees things, the concept of human nature is one that has had significant influence on humans. Consider, for example, how the Marxist image of human nature has exerted enormous influence on human societies as Marx’s ideas have taken hold and changed how humans live: ‘The practical impact of ideas about human nature […] can last for centuries’ (p. 46).

I have already suggested that Mameli offers a proposal, albeit a very loose one, that escapes Nathan’s scepticism about the very possibility of defining human nature. For Mameli, human nature in general consists in ‘all our important phenotypic traits and differences’ (p. 104). Specific accounts fill in the details of human nature in different ways, depending on what makes traits ‘important’. ‘Importance’ itself derives from the downstream relevance of traits for social and political projects. Mameli also hints, if only very briefly, at a potential payoff of the highly permissive range of possible ways of filling in these details. It is reasonable to suggest, says Mameli, that ‘important’ human traits are not those that all people actually have; instead, they are traits that all people might plausibly come to have, given the right supporting environments and institutions. This opens up a way to think about the relationship between an account of human nature and a commitment to forms of equality and social justice that further supplements Nathan’s approach: ‘Instead of seeking common humanity in the nonexistent “Man in general” we might see it as something to be constructed’ (p. 115); that ‘construction’ would make knowledge of human developmental biology and of forms of human socialization fundamental for its role in informing this transformation.

Mameli’s book is compact, original, erudite, and beautifully written. Does it leave room for responses from those who are sceptical of human nature? I have just one suggestion. On Mameli’s account, ‘Having ideas about human nature […] is part of human nature’ (p. 124). He is also keen to remind readers that ‘Human nature is not fixed and immutable’ (p. 128). This means that the ideas we are prone to articulate are also potentially malleable, including our use of the human nature concept itself. A philosopher might aspire, on emancipatory grounds, to alter this aspect of how people tend to think and talk. Here is a potential point of instability in the picture Mameli offers. I take it there is no chance—at least not for as long as humans continue to exist, and for as long as they continue to have ambitions for their forms of social life—that it will cease to be important to allow what we know about various traits of humans to inform our social and political projects. Some human traits will be reckoned as fundamental in the light of those projects, and there will be shifts in these fundamental traits as our knowledge and ambitions change. In these respects, Mameli’s overall argument for the ongoing importance of a ‘channel of communication’ strikes me as significant, and sound. Even so, it is not inevitable that the term ‘human nature’ will be used to flag up information that flows through this channel.

Mameli briefly mentions that ‘the human condition’ is a reasonable alternative term to designate the channel of communication. If Mameli is right to draw attention to the impact of philosophers’ ideas on human praxis, then he cannot claim that it is wishful thinking to suppose that people might eventually drop ‘human nature’ and replace it with an alternative term, or set of terms. Instead, an argument for preserving ‘human nature’ needs to focus on the comparative advantages of that label. Here it is relevant to pay attention to empirical work suggesting misleading and troubling aspects of thinking in terms of organisms’ ‘natures’ (for example, Linquist et al. [2011]), and to the comparative ease with which a term like ‘the human condition’ allows one to take account of forms of social and technological relations that may not be suggested by the term ‘nature’. It is also relevant to highlight that ‘the human condition’ more easily evokes a set of changeable and variegated features of the human population, rather than features of each human individual. There are reasons to think that the terms used to describe the channel that links scientific work to social and political ambition can influence the ease with which different forms of information flow along that channel. Mameli’s defence of the notion of human nature is an important moment in the literature on this topic, but it seems to me that scepticism about human nature has not quite been defeated yet.

Tim Lewens
University of Cambridge
tml1000@cam.ac.uk

References

Godfrey-Smith, P. [2014]: Philosophy of Biology, Princeton, NJ: Princeton University Press.

Heyes, C. [2018]: ‘Human Nature, Natural Pedagogy, and Evolutionary Causal Essentialism’, in E. Hannon and T. Lewens (eds), Why We Disagree about Human Nature, Oxford: Oxford University Press, pp. 76–91.

Hull, D. [1986]: ‘Human Nature’, Proceedings of the Biennial Meeting of the Philosophy of Science Association, 2, pp. 3–13.

Kronfeldner, M. [2018]: What’s Left of Human Nature? Cambridge, MA: MIT Press.

Laland, K. and Brown, G. [2018]: ‘The Social Construction of Human Nature’, in E. Hannon and T. Lewens (eds), Why We Disagree about Human Nature, Oxford: Oxford University Press, pp. 127–44.

Lewens, T. [2012]: ‘Human Nature: The Very Idea’, Philosophy and Technology, 25, pp. 459–74.

Linquist, S., Machery, E., Griffiths, P. E. and Stotz, K. [2011]: ‘Exploring the Folkbiological Conception of Human Nature’, Philosophical Transactions of the Royal Society B, 366, pp. 444–53.

Machery, E. [2008]: ‘A Plea for Human Nature’, Philosophical Psychology, 21, pp. 321–29.

Ramsey, G. [2023]: Human Nature, Cambridge: Cambridge University Press.

Sterelny, K. [2018]: ‘Sceptical Reflections on Human Nature’, in E. Hannon and T. Lewens (eds), Why We Disagree about Human Nature. Oxford: Oxford University Press, pp. 108–26.