Transhumanism within the Natural Law: Transforming Creation with Nature as Guide

Abstract

Transhumanism is an unsettling prospect for proponents of a natural law ethic. The goal of transhumanism is to fundamentally alter our human nature, while the natural law tradition relies on this nature for producing normative claims. The tension seems clear. But beyond the need to explore this underdeveloped relationship, it may be that natural law provides precisely the sort of ethical framework—a framework centered on human nature—for best evaluating transhumanism and bioenhancement technologies. Building on the work of Jason T. Eberl and Brian Patrick Green, I articulate how a Thomistic theory of natural law can guide us in a brave new world. Along the way, I note ways in which both Eberl and Green are too limiting in their interpretations of natural law, but in offering these critiques, I hope to bring out how natural law proves an invaluable guide for navigating life in creation—even a creation that has been tampered with.

Transhumanism is an unsettling prospect for proponents of a natural law ethic. The goal of transhumanism is to fundamentally alter our human nature by incorporating radical enhancement technologies, while the natural law tradition extrapolates from this nature our teleology and an ethic rooted in human flourishing. The tension over human nature seems clear. It is perhaps understandable, then, that few efforts have been made to analyze the two together—why waste time proving out the contradiction between these two projects? But beyond the value in pursuing this underdeveloped relationship, it may be that natural law provides precisely the sort of ethical guide—a guide oriented by human nature—for best evaluating transhumanism and bioenhancement technologies.

Some theologians and philosophers have already begun to point in this direction. Celia Deane-Drummond (2003), Shannon Vallor (2016), and Neil Messer (2006) are just a few of those working today who have incorporated the insights of Thomas Aquinas and an emphasis on virtue into conversations regarding transhumanism (see also Robinson 2008; Siep 2010). For each of them, Thomistic virtue ethics is the most promising way forward in a world of constant technological upheaval. Of special note, however, are Jason T. Eberl and Brian Patrick Green, both of whom foreground nature in their analyses of transhumanism.1 Taking up four classes of human enhancement—cognitive, physical, emotive, and moral—Eberl argues for a Thomistic appraisal that affirms cognitive and physical enhancements (with definite caveats) while remaining skeptical of emotive and moral enhancements that may deter us from genuine human flourishing. Green, operating at a more abstract level, similarly claims that a natural law ethic may limit what enhancements are appropriate for the species, even as such an ethic becomes harder and harder to apply in a world unrestricted by natural limitations. I take both of these projects to be helpful steps forward for understanding how a Christian theory of natural law can guide us in a brave new world. Yet, I will argue that both are too limiting of enhancement technologies—that, in the case of Eberl, he oversells the difference between moral bioenhancements and traditional moral improvement, and that Green is too pessimistic regarding the ongoing relevance of natural law in a posthuman future.

In taking up these concerns, my intention is to show that, despite some apparent tensions, natural law is particularly suited for ethically guiding the development and use of bioenhancement technologies. I do this by building on the work of Eberl and Green, which I take to also be affirming of natural law’s applicability, but in critiquing elements of their projects, I hope to improve our ability to reason according to the natural law and to demonstrate that the natural law tradition is not primarily dismissive of—and even at times is affirming of—transhumanism. To this end, I begin by defining what I have in mind in discussing transhumanism; in particular, I defend my use of “transhumanism” rather than something like “bioenhancements” and in distinction from the intellectual movement of Transhumanism. From there, I offer a broad sketch of Thomas Aquinas’s theory of natural law and how it applies to transhumanism. Then, in the following two sections, I take up the work of Eberl and Green individually, first examining virtuous decision making alongside Eberl, then exploring with Green the future relevance of the natural law tradition. I conclude by rehearsing the primary features of a natural law ethical framework, emphasizing how the tradition proves an invaluable guide for navigating life in creation—even a creation that has been enhanced.

1. Transhumanism as Radical Enhancement

Transhumanism is a relatively recent phenomenon, its principal orienting concern articulated in the belief that “current human nature is improvable through the use of applied science and other rational methods, which may make it possible to increase human health-span, extend our intellectual and physical capacities, and give us increased control over our own mental states and moods” (Bostrom 2005, p. 202). At its most basic level, transhumanism is the broad affirmation and use of technology that moves beyond therapy—changes to a person that make them more like typical humans (e.g., healing them of a disease, replacing a missing limb)—in favor of enhancement—changes that take a person beyond typical humans.

This distinction between therapy and enhancement is, as one can easily imagine, a disputed one. It may be an intuitive differentiation to say that some technologies remedy problems while others give added advantages, yet when under any stress, this differentiation begins to buckle (see Cole-Turner 2011, pp. 3–4). For example, while some technologies may operate as therapy in one context, in another they might work as enhancements—consider how Adderall helps those with attention deficits to focus while also granting those without ADHD the ability to hyper-focus. Or, even if a technology is always enhancing for an individual, it may not seem to radically depart from the potential of humans as a whole, such as a brain implant that increases IQ but only to an extent that falls within the realm of human genius. Other difficulties for the distinction between therapy and enhancement stem from its idea of “typical” and therefore something like an Aristotelian concept of natural kinds—hardly an uncontroversial assumption given our knowledge of evolutionary biology. Yet for my argument, I take for granted that we can speak meaningfully regarding nature, that humans at least make up a category of being with particular forms of life.2 So while defending a strict distinction between therapy and enhancement is unnecessary for my project, I am interested in what might be called radical bioenhancements, future technologies that would clearly threaten one’s nature—that could augment our bodies to such a degree that we are no longer the same sort of thing and may even be part of a totally new species. Under this umbrella, enhancements represent a variety of technological advancements, ranging from the biological to the virtual; they may include pills that make us more patient, artificial limbs that make us stronger, microprocessors that allow our minds to learn and communicate instantaneously, or, in one of the more radical scenarios, computers that grant immortality to uploaded consciousnesses.

These sorts of enhancements are normally identified with a normative and intellectually sophisticated conception of Transhumanism, a way of thinking most commonly associated with the intellectual movement that developed during the 1990s under the philosophical guidance of Max More, Nick Bostrom, Natasha Vita-More, Ray Kurzweil, and others. This form of Transhumanism comes with an explicit philosophical outlook, as demonstrated by its various advocates. Bostrom describes it as a desire to “achieve a greater degree of control over our own lives” (Bostrom 2003, p. 494). Others may emphasize more measurable programs, like conquering “human aging and the finality of death” (Vita-More n.d.) or avoiding future cataclysms (e.g., Kaku 2018; Persson and Savulescu 2012), but in each articulation, there is the underlying dream of humans (or their posthuman descendants) taking complete control of their fate. And it is over this Babelesque aspiration that much ink has been spilled and toward which much theological ire has been directed.

In contrast with this vision of Transhumanism—which I take to be irreconcilable with the Christian conception of grace—my argument is primarily concerned with transhumanism. Setting aside Transhumanism’s particular view of progress, with its will to power, drive for control, and promethean understanding of humanity, I concern myself with transhumanism as a general affirmation and use of technology for enhancement. This version of transhumanism is concerned with a class of technology—radical bioenhancements like synthetic blood, exoskeletons, brain implants, etc.—that offers a means toward achieving immediate goals, not ultimate goals.3 Such a way of using the term can be found in different Christian thinkers, including Eberl and Green, as well as others like Karen Lebacqz or Adam Pryor (e.g., Lebacqz 2011, pp. 51–62; Pryor 2011, pp. 19–44).4

Of course, one might ask, why not exclusively use the word “bioenhancement”? That seems like a less contentious term. And while that may be so, transhumanism has the two advantages of (1) being the word more familiar in the public consciousness to describe these technologies, and (2) communicating the importance of changing human nature by these technologies—precisely the issue at the center of this examination. Thus, my intention in using the term transhumanism is to foreground the way in which these enhancement technologies go beyond mere tools and threaten to alter our human nature. It is in the face of such technology that the natural law tradition, by reflecting on our human nature, remains a relevant ethical framework, guiding our incorporation of technology and even at times affirming the technological transformation of our nature.

2. Transhumanism within the Natural Law

The Christian tradition of natural law has as many variants as it has expositors and interpreters, ranging from Paul’s New Testament writings to the Church Fathers and Augustine to the scholastics and the current wave of new natural law thinkers—not to mention ancient and modern philosophers and theorists from other faith traditions. Rather than try to do justice to even a small sampling of these theologians and jurists, this examination focuses on the articulation of natural law by Thomas Aquinas, particularly as interpreted by Jean Porter. Aquinas not only represents the dominant expression of natural law in Christian theology, but his teleological focus, emphasizing reasoning backward from our ends to normative claims, makes his understanding of the natural law uniquely suited for discussing the future of human nature.

According to the medieval theologian, “natural law is nothing else than the rational creature’s participation of the eternal law”—the eternal law itself reflecting the Divine Reason that governs the universe (Aquinas 1981, ST I-II.91.1–2). Such a definition places at the center of natural law theory a conception of the cosmos as ordered, suggesting both the rationality of all creation and the goodness of creation.5 This further allows Aquinas to identify the teleological character of the natural order: from the eternal law, all things in nature “derive their respective inclinations to their proper acts and ends” (Aquinas 1981, ST I-II.91.2). That is, for creation to participate—biologically, physically, rationally—in Divine Reason, it is for all things to be directed toward their own respective teloi and for each of these to be bent toward a converging telos in God. In the case of humans, this telos is found ultimately in the beatific vision of God and more immediately in the goal of human flourishing. To pursue this end is natural; to deviate is unnatural. It is through the cultivation of virtue that humans approach their heavenly telos.

To fill out this brief sketch of Aquinas’s natural law (and its importance for transhumanism), it is important to recognize the breadth of nature. While the “nature” at the heart of Aquinas’s theory of natural law is most often the nature of humans, the scholastic conception of nature takes on multiple valences, including: the ordered reality of creation, the intrinsic characteristics of a kind of creature, the human capacity for rational judgement, and God’s will for creation (Porter 1999, p. 77). So even if human nature stands at the forefront of Thomistic references to nature, the category remains exceptionally broad. This suggests, more than anything, the integration of all creation. The human telos found in our flourishing and communion with God is intimately intertwined with the telos of rocks and trees and all created things. Humanity’s distinctive rationality is bound up in the ordering of the cosmos, is bound up in the will of the Father.

Such a broad understanding of nature undergirding the natural law tradition culminates in the wide-reaching moral principle “action follows being”. Green explains the scholastic motto in this way: “by knowing what something is (its nature), we can know something about how it should act (its ethics)…. Beings should act in accord with their natures because, in following God’s providence, doing so leads toward virtuous excellence and happiness” (Green 2015, p. 201). This principle captures the thrust of the natural law tradition not only by recognizing that because creation participates in the eternal law (being both providentially good and directed toward the good), all action is situated within that directedness, but also by recognizing how this directedness permeates all creation. All things subject to Divine Providence—all being has a telos. And while some things are unable to deviate from their given telos (fire will always glow and give heat), other things, namely rational animals, make choices to either fulfill their natural telos or depart from it. Therefore, right action should not be thought of as something foisted on—borrowing from Jean Porter—the “formless contingencies of human existence” but rather as something incorporating and completing the necessities of our creaturely existence (Porter 2005, p. 50). All of material reality is meaningful for human action.

An important nuance of this principle is that a natural law ethic is not inherently self-reflective—that is, action flows out of being, but being does not necessitate itself. Reasoning from our inclinations can lead to actions that just as easily fulfill the imperatives of nature as it can actions that transform or transcend that nature. Thus, something’s origins in human ingenuity rather than biology or in its departing from biological processes does not discredit it as unnatural, in the scholastic sense. It is simply nonnatural, in the way that all human convention or technology is. The pejorative of unnaturalness is reserved for evils that misdirect creation from its good ends (see Porter 1999, pp. 314–15). The natural law is not constrained by who we are today but is open to our future judgments regarding biological intervention. Aquinas recognizes this possibility:

…nothing hinders the natural law from being changed: since many things for the benefit of human life have been added over and above the natural law, both by the Divine law and by human laws. [Furthermore] the natural law is altogether unchangeable in its first principles: but in its secondary principles… it may be changed in some particular cases of rare occurrence, through some special causes hindering the observance of such precepts, as stated above.

(Aquinas 1981, ST I-II.94.5)

It is the mutability and contextuality of the natural law that keep it relevant for the mutability of bioenhancement; the natural law responds to the unfolding of transhumanism by the constant criteria of human flourishing.6

While the principle that action follows being does not require the maintenance of a particular state of nature, it does set the foundation for a Thomistic theory of action and virtue. For Aquinas, because “each thing is inclined naturally to an operation that is suitable to it according to its form… [and because] the rational soul is the proper form of man, there is in every man a natural inclination to act according to reason: and this is to act according to virtue” (Aquinas 1981, ST I-II.94.3). We learn how to act through reflection on nature, especially our own nature as human beings. Aquinas’s idea of human nature took on some general features (existence, rationality, physicality, sociality), but his focus remained on how our inclinations render our functions and activities intelligible—that is, how human nature mirrors what it means to flourish. This leads, then, to the primary epistemic feature of natural law theory, which is that people come to know the law through both pre-rational inclinations and rational reflection on their human nature. According to Porter, these ways of knowing are efficient exactly because the natural order is directed toward good ends:

Because the pre-rational components of human nature are intelligible, they are amenable to rational analysis and potential reflection, on the basis of which the human person is able rationally to pursue the same ends that other animals pursue through instinct. At the same time, reason itself also creates possibilities and generates aims that are distinctively human, and it also belongs to practical reason to pursue these aims, and, furthermore, to bring order and coherence to the various ends of human life.

(Porter 1999, pp. 97–98)

The pre-rational is often emphasized in discussions of natural law so that human intuition—the law written on the heart, to borrow from Paul—becomes normative. Yet, for Aquinas and the scholastics, the pre-rational and the rational work in tandem. The components of our nature that dispose us to different desires and ends are intelligible parts of the natural order, and so humans are thus able to reflect on their inclinations by the first principle of practical reason, “good is to be done and pursued, and evil is to be avoided” (Aquinas 1981, ST I-II.94.2). Moreover, human reasoning abstracts and moves them far beyond empirical observation; it incorporates the insights of philosophy, the community, and, most of all, the divine law through Scripture. In this way, our natural inclinations do not provide one-to-one ethical rules but are always subject to reason and a wider situational context—nature, again borrowing from Porter, “underdetermines” morality.7 Thus, understanding the relation of our pre-rational dispositions to our world of rational conventions always requires the specific virtue of prudence.

According to a natural law tradition, then, bioenhancements ought to first be assessed through reasoned reflection on our being as known through our natural inclinations. The morality of technology is not divided along therapeutic-enhancement lines or known by its maximizing of pleasure or minimizing pain, but by how it contributes to human flourishing, that is, how it fulfills the basic features of our humanity. A hypothetical brain-implant that aids us in simple arithmetic or a drug that eliminates our susceptibility to future viruses—each of these qualifies as a technology contributing to our human flourishing, particularly the parts of our being that aim for health and for truth. But, again, in a theology of natural law, it is rarely as simple as reflecting on our basic desires to know what we ought to do. We cannot navigate life by mere reflection on our nature or relying on our inclinations, but rather must incorporate the insights of reason and communal wisdom. So, for example, even if our bodies are constructed for reproduction, the faith community might argue that the ability to genetically design our offspring may in some ways be destructive of our flourishing; or, if a particular enhancement required a tradeoff sacrificing longevity for increased memory and rationality, some might appeal to higher spiritual goals in order to choose such a technology in spite of their natural inclinations toward health.8 Ultimately, a natural law ethic does not take nature to be overriding in our moral reasoning, but it always incorporates material reality into that reasoning.

2.1. Eberl and the Virtuous Human

This understanding of natural law can benefit our ethical reasoning in particular cases, including emerging discussions over moral enhancement. Throughout history, there have been many strategies for moral improvement; most of these, falling under the umbrella of moral education, are familiar practices, like enacting policies and legislation, undergoing spiritual disciplines, and infusing children with familial values. Yet some have argued that something more radical is needed: using technology for moral enhancement (see Persson and Savulescu 2012). This can take the form of something like pharmaceuticals or brain implants, anything that could help us become more ethical. The idea is that moral enhancement technology that aims at cognitive and emotive enhancement—technology that could affect certain dispositions like altruism, fairness, or temperance—may be our best option for slowing climate change, ending racial conflict, or bringing about global peace.

Taking seriously the possibility of moral enhancement, Jason Eberl offers a critical assessment of the technology. Whereas other enhancement technologies, those used for physical or cognitive improvement, can more easily be understood to directly aid in our human flourishing (keeping us healthy, better equipping us to pursue truth), moral enhancements could potentially endanger crucial elements of our lives as rational animals (Eberl 2014, pp. 289–310). In particular, certain forms of bioenhancement may threaten our ability to make our own, self-directed decisions. To use such a technology is to threaten one’s agency and thus choose action that does not follow from one’s nature as a human being. Eberl maintains that, in order to retain our moral autonomy, moral enhancements should only rightfully be used to align our will with our second-order desires (our desires regarding our desires) and not to simply override those second-order desires. And even then, this leaves our moral telos up to us, and the possibility remains that our ethical framework may be fundamentally misguided (Eberl 2019, p. 522).

Even as he recognizes the dangers and limitations of improvement, Eberl argues that the possibility for moral bioenhancements to help us align our first-order desires with our second-order desires is a clear good and that technology may provide us the means necessary to overcome our “moral weakness of will” (Eberl 2019, p. 509). Thus, for moral bioenhancements to be legitimate, they must work in accordance with our prudence, the central virtue by which we shape our desires and transform them into volition. Within a Thomistic framework that sees the body’s instrumental role in developing virtue, Eberl identifies that prudence is open to enhancement through environmental and physiological change. He follows Aquinas in recognizing that fostering perception and the health of the body—things that can clearly be augmented with technology—is crucial for developing virtue and that the various elements of prudence—memory, understanding, shrewdness, reasoning, and docility; foresight, circumspection, and caution—could all theoretically be enhanced. Therefore, on multiple fronts, the virtue of prudence seems open to technological improvement and, thereby, our moral lives.

Still, Eberl’s worry that moral enhancements would lack authenticity and effectiveness dominates his discussion of the technology. He explains that moral enhancement would likely work by limiting or promoting certain emotional tendencies—for example, they might temper our aggression or incline us to tell the truth. To illustrate this, he describes a mother who is prone to impatience but wishes to better herself. In a stressful situation (say, one with an aggravating child), she may choose to respond by leaving the room, closing her eyes, and counting to ten as she takes deep, purposeful breaths—or she might choose to take an as-yet-uninvented pill that alters her neurochemistry to calm her down and help her be slow to anger in that moment. Eberl contends that both of these potential actions stem from a choice on the mother’s part and thus reflect some sort of “moral merit”. Yet, the option to pop a pill still seems different; he worries that it may not lead to the “agent’s authentic and stable change of character to become a more patient person” (Eberl 2014, p. 205)—though he acknowledges that research would need to be done on the lasting effects on the agent’s neurochemistry—and that a pill runs the same risk as all drugs of being taken at improper times and in improper conditions.

But how is any of this qualitatively different from the traditional practice of taking a breath and counting to ten? We are inclined to think that repeated practices will build internal habits, but we are also each familiar with individuals who seem to be getting worse as they try to develop their discipline or whose anger actually builds as they count to ten through clinched teeth. There’s simply no guarantee. Moreover, the choice to step out and take a breath is a choice that requires prudence in exactly the same way as the choice to consume a drug—there is no moral merit for a mother who steps away from a crying baby that needs tending to, whether she is counting to ten or not. The decision to practice a discipline is just as much a “laudable desire” (Eberl 2014, p. 305) as the prudent decision to take medication. And in addition to right desire, the acts themselves show a similar level of agency. It might be said that in using an enhancement, it is good that the mother acts patiently, but there is no moral act going on—whereas the practice of breathing and counting requires active participation by the agent, in the other scenario, a pill is doing all the work. But crucially, by taking the hypothetical drug, the mother both accomplishes the good of showing patience in an aggravating situation and makes the moral choice of choosing to encourage particular neuropathways in a particular situation.

Eberl continues his concern over agency in reference to the proposed interdisciplinary Genetic Virtue Project. This work would investigate the potential for moral enhancement through genetic science and engineering to “complement, not replace, the Aristotelian model for virtue acquisition” (Eberl 2014, p. 306), so as “not to make persons virtuous but to make them better equipped to learn how to be virtuous” (Walker 2009; quoted in Eberl 2014). This attitude would seem to align with Eberl’s concerns that virtue is developed by individuals in their formation of habits and that this process has a physiological dimension. Nonetheless, he remains unconvinced. All of the concerns already expressed still linger, and specifically, he fears that we can never be sure—from an objective vantage or subjectively—whether genetic manipulation is really complementing the cultivation of virtue or is creating a “mere simulacrum of true moral virtue” (Eberl 2014, p. 306). But again, what is the difference here between virtue and “virtue”?9 Undoubtedly, virtuous habits reflect some activity of the brain, so there should be no contradiction in affecting the composition of the brain for the development of virtue. For instance, suppose it takes 21 days to cultivate a helpful habit, and over those three weeks, we expect real physiological changes to occur in the brain as that habit is formed. If a person received treatment that made it easier for them to learn a habit—maybe in 14 days—would their new disposition become somehow less legitimate? It seems that Eberl’s worry ultimately boils down to fears regarding our free-will: that by using the powers of genetic engineering, we might accidentally (or purposefully) short-circuit our autonomy and produce some sort of well-behaved zombie. Eberl does not pursue this line of questioning, and understandably so. Yet while circumventing our free-will is a theoretical possibility, it does not seem to be taking seriously the potential of the proposed science, the legitimacy of the subjective claim that “I feel like I am making these decisions of my own accord”, and the fact that cultivating virtue is always a natural phenomenon.

In these examples, Eberl helps us get at what moral decision making and the cultivation of virtue look like in the Thomistic tradition. It becomes clear how our inclinations and forms of life guide our actions. (I need to take care of this baby, but I also need to keep my sanity). More than this, Eberl brings out the complexities of our choices and how our inclinations are always filtered through our moral reasoning. (Doing X may help with the baby and my sanity, but will it help in the future? Will I give up my free-will?) Still, his fears that moral enhancements would depart substantially from traditional forms of moral improvement seem overblown. Following an ethic from nature, we could reasonably hope to accommodate such technologies into our lives.

2.2. Green and the Future of Nature

Another way in which a theory of natural law helps us think about transhumanism is by affirming the goodness of nature while recognizing its malleability. This insight is crucial as we speculate about the future of humanity and what moral reasoning will look like as technology transforms nature. Brian Green describes the malleability of human nature by drawing on Aquinas’s conception of first (universal, biological) nature and second (individual, cultural) nature. While in previous times only the latter was mutable, now too the former is subject to shaping by our will. This is clear for Green because, “If action follows being, and our capacity for action has changed, then this implies that our being may have changed as well” (Green 2015, pp. 203–6). He thus recognizes that what we call human demonstrates some level of fluidity, that we are not human in the same way our ancestors were humans, and that we should not expect our descendants to be either. Following this argument that the scope of our action reflects our ontology, the radical open-endedness of our ability to act out our will by the powers of technology suggests that we are moving toward an entirely new nature, or, in Aristotelian terms, toward “pure potency” (Green 2015, pp. 206–8, 211).10

Moreover, changing our nature is not something we should expect to avoid by following the natural law—for even as we pursue our natural telos of human flourishing, we may at times find ourselves disrupting our current nature. This could happen in small ways, as a technology achieves some good even as it transforms our ordinary ways of living in the world (for example, brain-computer interfaces may foster our flourishing through increased social connection even as they produce totally new ways of blessing and harming others we encounter in the world), or it could be more radical as enhancements perfect and eliminate elements of our nature—if technology can facilitate procreation, social bonding, and intense pleasure, what need is there for the often hazardous practices of sexual intercourse and biological reproduction?

This potential for change leads Green to suggest, “If transhumans obtain new powers for action, we might have to classify them as possessing different natures from current humans and as having different ethical expectations” (Green 2015, p. 206). He worries that, along with new bodies and new ways of engaging the world, a new nature brings with it new moral requirements, that much of what we currently take to be good will no longer apply. Reflecting on Aquinas’s inclinations from human nature (to survive, reproduce, educate the young, live in society, and seek truth), Green outlines some of the repercussions for transhuman beings:

For example, they may not need to reproduce biologically. They may just need to copy themselves electronically, thereby eliminating the need for education as well. Would their lack of need to fulfill this basic human inclination be “evil” or just unnecessary? Because they could have different natures, these inclinations might simply no longer apply to them. Whether transhumans would live in society is an open question. If they did not, then survival and truth seeking might be the only inclinations transhumanists have in common with regular humans.

(Green 2015, p. 210)

At some level, this is indisputable. What is ethically demanded of us is contingent on our material potential; that much is affirmed by the natural law tradition. Yet already, Green is too quick to let certain moral norms fly out the window. For example, he suggests that persons might not need to live in a society, presumably because they stay in some virtual environment or because they do not need others to meet their bodily needs. But does this follow? If we are still rational creatures in this scenario, then our need to interact with, to love and be loved, to support and to be checked by others all still remain; just because a being can live without others does not mean it would be good for them to do so.11 Again, this is not to disagree with Green that transhumans may have different moral requirements than current humans and that there may come a day that the five inclinations Aquinas identifies would no longer apply—but it is to suggest that Green’s static understanding of the natural law, specifically of the relationship between nature and telos and what our inclinations are actually telling us about what it means to flourish, may be stifling of a natural law ethic.

The mutability of our moral requirements leads to a wider concern for Green: that the natural law lacks ongoing relevance for ethical decision making in a transhuman future. While he is able to affirm that the natural law as an approach to ethics “remains immutable [because] action will always follow being”, he argues that such an approach loses viability on account of how “indeterminate nature may become or how relatively useless (given that indeterminacy) the method may become” (Green 2015, p. 213). That is, as potency surpasses actuality and as our wills direct us more than our biological nature,12 the guidance that natural law offers will become increasingly less useful. Green is going beyond merely arguing that posthumans would have different values—that much is beyond dispute (see Bostrom 2003, p. 495)—and makes the more radical claim that our way of getting at those values would need to change. Because whatever we may become would be in such a state of flux, constantly changing along with our whims, an ethical framework based on reflecting upon ourselves and our origins would be unable to hook on to anything, unable to make any sort of normative claim. Green can thus speculate, “Kantian and utilitarian ethics might actually be more appropriate for transhumans than virtue ethics or natural law would, since under conditions of radical will and indeterminacy, habits of action and nature might become reduced” (Green 2015, p. 210).

To be fair, the penultimate section of Green’s chapter is concerned with how to best respond to or even avoid this fate—a “dynamic ethic for a dynamic nature”—but it is unclear that there is any need for such a response. The worry that being would cease to be a helpful guide in a world of indeterminacy seems to misconstrue the natural law. Green’s clearest articulation of the natural law runs as follows:

For natural law to work, the entelechies (the built-in natural purposes, or telei) of creatures must be known. Being determines action because natural being is intrinsically teleological—nature aims toward something. If we can determine that transhumans still have a natural entelechy, then their ethics could be read from their natures, not their wills.

(Green 2015, p. 209)

While this description is open to interpretation, Green’s concerns over natural law’s ongoing relevance seem to suggest that by identifying ends with entelechies, he is treating telos like something that extends from nature—rather than as something objective that God’s provident wisdom has directed nature toward. Moreover, his understanding implies that the telos of any given thing is discrete, independent of all other goods, so that a changing nature has no teleological holdover from one nature to another or that a being could potentially not “still have a natural entelechy”. But this is not scholastic natural law. The Thomistic vision of teleology is like a tree: all of creation finds its end in God, the trunk of the tree.13 Other ends branch-off of this so that, for example, all things share a common limb in their desire to preserve their being. But there are also more proximate ends—smaller branches—such as the rational creature’s desire to live in society. All of what it means to flourish is related, and all of creation (that is, all that exists, organic or silicon) participates in this ordering toward God.

Therefore, the natural law remains a guiding ethic, first, because being—the way something is—always has a way that is best suited to it, a way that will lead it along the tree of reality closer to its flourishing and to God. Whether or not a posthuman is better off than a modern person, the being of a posthuman still lends itself to a form of flourishing. Second, the natural law guides us through its appreciation of the external world, so even as our environment rapidly changes by humans’ manipulation of nature, the natural law guides our eyes from the world to its telos. As participants in the community of creation, we witness how all being gestures towards a way of living, towards the telos of creation, towards the flourishing of God’s handiwork, and towards divine communion. And because there is always some sort of being (nature) to reflect on, a natural law ethic will always recognize this gesturing. Reasoning from reality toward the good will never be obsolete.

So, yes, virtue ethics may be less efficient compared to other ethical theories because of our changing relation to habit; yes, if our definition of a helpful ethical framework is simplicity or consistent admonitions, then the natural law will always be less helpful than Kantianism or utilitarianism. But the natural law nonetheless remains relevant because of its insistence that creation, that our modes of existence in all their complexity, are not only value-laden but providentially ordered. And such an ethic should lead to noticeably different reasoning and results than, for instance, a utilitarian approach. If one’s aim is to maximize pleasure and minimize pain, then autonomy and agency may be expendable elements of the human person in our pursuit of a more just and pleasing world. Similarly, differences from a Kantian position prone to absolutist perspectives should be obvious. Whereas such an approach might ignore the moral nuances of situations, a natural law ethic, oriented by prudential reasoning, recognizes how enhancement technologies can offer legitimate goods or evils and can reason regarding their final contribution toward flourishing in any situation. Again, utilitarian and Kantian ethics will be simpler. Formulas for moral calculus and the categorical imperative provide ready-at-hand ethical tools to be applied in a variety of situations—and these tools may at times be helpful or even complementary to a virtue ethic rooted in nature—but because action always follows from being, the ability to reason from nature is always before us.

Of course, it should not be surprising that a Thomistic approach to ethics would be different from other approaches and does little to suggest if it is actually superior to those approaches. But hopefully, in tracing the ways natural law can continue to speak to transhumanist concerns, it has become clear that it offers a unique and robust mode of moral reasoning, reasoning that directs our attention toward God’s creation, its goodness, and its implications for our flourishing.

3. Looking Forward, with Synthetic Blood as an Example

In pressuring Eberl and Green, my intention has been to further develop the under-explored relevance of natural law to transhumanism, improving along the way our ability to reason by nature. By rehearsing the similarities between ordinary moral improvement and moral bioenhancements in dialogue with Eberl, we begin not only to see a Thomistic approach to transhumanism but also the openness of such an approach to new technologies. Green, for his part, helps us recognize from a natural law perspective how we can expect our values and moral imperatives to shift with a changing nature, even as I might reassert the utility of natural law to guide us amidst those changes. Tracing these contours of a natural law theology demonstrates that a Thomistic approach, rooted in creation, is precisely the ethic needed for thinking about bioenhancements.

Two key features highlighted in this examination should remain central for our moral reflection according to the natural law: First, action follows being. This is, again, the core insight of natural law, that because the cosmos is directed, we learn much about how we ought to live by reflecting on our nature and our material reality. Second, reasoning from our human nature does not commend definite moral actions but, rather, is opened up to prudential living. As Celia Deane-Drummond puts it, “The first principle of natural law, to do good, is not simply a matter of following one’s inclinations, but of fulfilling them in a certain way through the virtues” (Deane-Drummond 2003, p. 306).14 The habits of virtue are those that best navigate the natural order of creation, and foremost among these virtues is prudence, which is necessary for navigating the complexities and ambiguity of life in the world. Because nature in all its connotations is not enough to guide the moral life—because the inclinations of our human nature can be misinterpreted and the path toward good can be unclear—the natural law is thus a starting point and a confirmation of our moral choices, but it is left incomplete without supplementation from theology, philosophy, and the wisdom of communities that give direction to our inclinations and practical reasoning. In this way, the natural and the conventional are mutually interpreting and enforcing.

Though he does not explicitly appeal to the natural law tradition, Gerald McKenny outlines a framework for how this sort of ethic would work. Answering whether “malleability and indeterminacy render obsolete the notion that we look to our nature to determine what our good is”, he attempts to find a third way for conceiving of nature’s relevance, somewhere between preserving our being at the expense of technological growth and embracing our natural indeterminacy as a mandate for complete acceptance of bioenhancements (McKenny 2019, p. 240). Drawing on Aristotle (and citing Porter as well), he puts forward a method for incrementally assessing technologies; he suggests that we can imagine ways based on our nature that our nature might be made better through enhancement, which we can then pursue and incorporate into our reflection. He recognizes that we can make mistakes in this process, and so we must proceed carefully and dialectically. This sort of slow process in which one reflects on their being—what does my nature incline me toward? what would it look like to flourish? would a particular change be transforming or transgressing my nature?—and proceeds incrementally is the exact approach a natural law ethic lends itself to in the context of transhumanism.

A brief example might be helpful. Consider the development of a transhumanist technology like synthetic blood. At a very basic level, one might be initially skeptical of infusing foreign substances into their bloodstream—perhaps drawing on Christian wisdom, Levitical prohibitions, and that sort of thing. But reflection on the natural inclination for self-preservation, rational analysis of existing medical procedures, and better interpretive strategies would likely prevail. Next, one might worry specifically about the blood being synthetic, contrary to nature and outside of God’s created order. But again, such a fear is eclipsed by the recognition that human convention and ingenuity are often used to supplement and aid our natural prospering. Still, while some forms of synthetic blood might be deemed acceptable, such as those that help fight off common diseases, other more radical forms may appear off-limits, such as a future blood substitute that slows the aging process to a halt. When one looks to religious tradition and communal wisdoms, there seems to be conflicting messages on immortality: some suppose death is a beautiful part of the human condition that Christians approach boldly, while others point to it as the shadow of sin, the final enemy to be triumphed over. Can we find clarity by reflecting on the physical world or our natural inclinations? Again, there seems to be tension: we desire to preserve life, but there is also legitimate cause for concern that such radical enhancement might pull at the thread of a healthy society. Much of what our natural inclinations impress upon us—procreation, education, the need for others—assumes the cycle of generations and that one day we give what we have back to the earth. These possibilities are not meant as an exhaustive response to synthetic blood or immortality but hopefully demonstrate and affirm a dialectical way of reflecting on our material forms of life.

Part of my goal in this article has been to argue for the ways that a natural law ethic can be open to potential enhancement technologies and to gesture at an ethical guide beyond what those doing the best work on this question have supposed. But at this point, I want to affirm, along with Eberl and Green, that limitations still exist. Even as we remember that the natural law does not prohibit the nonnatural, there are countless ways that technologies can represent and foster the unnatural, ways of being that take us further away from flourishing and communion with God. Of course, what was considered natural or unnatural may shift—what was morally obvious before will change—but this is only part of nature’s further unfolding, requiring our on-going reassessment and reevaluation. We can never grow complacent in our singular understanding of nature, for even now, the ways in which reality directs us toward its telos are never static in any given moment but rather continuously manifesting. There is not a single path toward the goal of creation but, more often than not, a plurality of virtuous choices aimed toward that ultimate good. And it is an ethical framework centered on the natural law that is best positioned to mark out those paths, centering us on nature and the eternal truth that action follows being.