Davison, Andrew. Astrobiology and Christian Doctrine: Exploring the Implications of Life in the Universe. Cambridge University Press, 2023. Hardback, 407pp; $40; digital $40; paperback: $28.

The author of this book is also a guest on The Sed Contra Podcast, “Aliens and Soteriology,” hosted and produced by members of The Sacra Doctrina Project.

Introduction

For those who grew up reading and watching fantasy and science fiction, the imagination leaps to the existence of extra-terrestrial intelligent life as if to something per se notum. The scientist, philosopher, and theologian proceed at a more deliberate pace in such questions—if they make such ventures at all—and with good reason. Here, the ancient observation of Aristotle is apt: “On these questions, I say, it is well that we should seek to increase our understanding, though we have but little to go upon, and are placed at so great a distance from the facts in question.” (De Caelo, II.12) St. Thomas, commenting on this passage, says that “if what we shall say enables us to contemplate the truth of these doubtful matters, then what seemed to be doubtful at the beginning of our inquiry will be seen not to be devoid of all explanation.” (In De Caelo, lib. II, lect. 17, n. 457)

Such a spirit of inquiry pervades the insightful explorations and gentlemanly prose of Andrew Davison’s Astrobiology and Christian Doctrine. Davison, formerly the Starbridge Professor of Theology and Natural Sciences at Corpus Christi College and recently appointed Regius Professor of Divinity at Oxford, has succeeded in a theological trek where few have gone before. Drawing on the range of the Christian theological tradition, his inquiry proceeds at two mutually reinforcing levels: a natural theology of creation that informs arguments about the fittingness and possibility of rational life beyond the human domain as well as a strictly theological speculation about the implications of such a possibility for our understanding of the Trinity, the Incarnation and the person of Christ, and eschatology.

Davison writes primarily to “members of the Christian churches” (368; all parenthetical numbers refer to Astrobiology and Christian Doctrine). He states that

one of the principal aims behind this book has been to move the discussion of theology and astrobiology beyond the relatively restricted number of standard historical texts deployed in writing on the subject, to others that were not directly addressed to, or occasioned by, thoughts of life elsewhere in the universe, but which nevertheless could bear directly upon the topic. (232)

Indeed, from among the various Christian churches and their authorities and thinkers, Davison shows that, despite a host of reactions to the very worth of pursuing such a topic, there is precedent even pre-dating Galileo’s telescope for the necessity and benefits of such properly theological speculations. The inquiry itself calls for deepening our insights and appreciation for the plenitude of God’s creative wisdom and the scope of His redemptive love. In what follows, I will review some of the book’s more striking and salient points and then offers some concluding reflections.

Astro-Theological Investigations

Davison’s book is divided into five parts: on creation, revelation and theological knowledge, the imago Dei, soteriology, and eschatology. Part I discusses the possibility of life—intelligent or otherwise—on worlds other than our own, all within the modality of the theology of creation. Are there other such worlds to begin with? The first chapter reviews theological perspectives on the answer to this question, from the ancient Greeks to pre-Big Bang astronomy. That Christian thinkers countenance intelligent life other than our own is explored in the second chapter’s discussion of angels. The third chapter treat of the nature of life, in particular how the term is used analogously. The fourth and final chapter of the first part of the book considers arguments from fittingness that the cosmos is not empty of biological life. The theme of what befits or what is “behovely” (204–205) recurs throughout the book. For instance, St. Albertus Magnus considers the possibility of other worlds but rejects them on such grounds,

since it would set up a plurality of places or communities between which exchange would not be possible, yet the good of the whole is constituted by the interrelation of its parts. In writing this, Albert appears to assume that any other worlds would be inhabited, since isolation would stand particularly against ‘civic interchange’ (commercione civium). (25; see St. Albertus Magnus, Commentary on De Caelo et Mundo, book 1, tr. III, ch. 6, p. 81)

Arguments for and against the “plurality of worlds” abounded in the history of theological encounters with astronomical discoveries, especially if proponents added heretical claims about Christological implications (32). However, “as Jacques Arnould has written, ‘the plurality of worlds passed from a status of heresy to that of a powerful argument for the rhetoric of natural theology’.” (37) Davison uses this history to lay his defense of the plenitude of the cosmos. Many are his allies here; for instance, Johannes Kepler considers the plenitude of life on our planet and asks if God has

“then used up all His skill on the globe of the Earth so that He could not, or all His goodness, so that He would not wish to adorn with suitable creatures other globes also?” Kepler thought not, and in that way, just as the idea of living stars and planets was waning the prospect of life on other astronomical bodies began to be taken seriously. (58)

Crucially, it is the analogical character of life which undergirds what some might see as mere arguments about possibilities. That biological life, which Davison analyses in broadly hylomorphic terms, consists in self-preservation or intentional self-movement does not limit the term. As he notes, God is most of all alive (73) and other things alive by participation. Here, one might consult Davison’s other work on analogy (“Machine Learning and Theological Traditions of Analogy”) and divine exemplarity (“‘He Fathers-Forth Whose Beauty Is Past Change,’ but ‘Who Knows How?’: Evolution and Divine Exemplarity”).

One must also be careful in thinking of life in the cosmos to the detriment of the inorganic realm. Against the quips of some that human life as a perfection in the universe would be a statue on too large a plinth, Davison responds in various ways, not only by suggesting plenitude as an answer, but also that “inanimate matter is not without form, beauty, or value.” (79) Indeed,

The emergence of life within the realm of the non-living is a shift of the highest significance. It is so profound, on a qualitative level, as to render quantitative comparisons otiose, such as contrasting the size or mass of what lives in the cosmos to the size or mass of what does not. (81)

Nonetheless, the size, age, and constitution of the cosmos are necessary conditions for life (92, et passim), and one might question, with Davison, whether nature that is habitable would be in vain without inhabitants.

Part II moves the discussion into more properly theological territory. If there is intelligent life elsewhere in the universe, why do the Sacred Scriptures make no mention of it? Furthermore, would there be limits to God’s revelation to other intelligent life? Is our revelation “contingent and terrestrial in expression” (98)? Davison does not think so. In particular, as the sixth chapter discusses, Trinitarian “language of Father, Son, and Holy Spirit . . . is not simply a matter of certain earthly categories being pressed into somewhat arbitrary service.” (98) Here again, he turns to the Thomistic doctrine of analogy to defend the non-arbitrary cogency of traditional trinitarian terminology. He even defends the idea of a sort of “convergence” in the form intelligent life would take such that the Augustinian psychological analogy of memory, intellect, and will could take root in an otherwordly revelation as well (124; and see 169–73). As to a lack of aliens in the Bible, in the fifth chapter (and elsewhere), Davison turns to the idea of divine accomodationism. God, the finest of teachers, adapts revelation to fit our capacities as well as what is necessary for salvation (104–109).

Davison focuses particularly on the topic of intelligent life and the imago Dei, especially as regards human uniqueness in creation, in Part III. This part engages, then, the various “masks” between man and the cosmos which theologians, philosophers, and scientists have cast. Chapter seven argues, for instance, that the discovery of heliocentrism is not a moral or ontological “demotion,” as it rather is a promotion of the lowly terrestrial (“the rubbish dump of the cosmos”) to the celestial (141). Furthermore, as the eighth chapter discusses, is it the case that the existence of the imago elsewhere would entail that the Bible “[misrepresents] entirely man’s relaton to God and the universe”? “But why should that be so? Why should human value be diminished just because other creatures share that upon which it rests?” (152) Davison discusses interpretations of the imago in what human beings are (a constitution view), in what we do (a role-based view), and in our relationships. Davison favors a position that accepts and harmonizes all three (156). The eighth chapter also discusses the similitude of creatures to God, traces (vestigia) of the Trinity in creation, and the distinction of imago from these: “Creation’s homage to plenitude is its multiplicity, and I would stress the same variety in the realisation of the imago dei” (166) and “Christian theology has nothing to lose in accepting that other creatures could bear the image of God” since “likeness is of its nature not a competitive matter.” (167)

In the ninth chapter, Davison considers in more philosophical and biological terms what it means for intelligence to be embodied. This includes a consideration of St. Thomas’s view “that there could only be one sort of rational animal such as ourselves.” (169) The teleological reasoning behind such a view places the Angelic Doctor’s thinking “surprisingly close to contemporary accounts of embodiment in cognition and convergence in evolution” (ibid.). Davison notes that converging lines of evolution producing similar functions or the contingency of possible forms of intelligent embodiment are curtailed in a certain way from a hylomorphic perspective, where matter is for the sake of form. At the same time,

we could justifiably say that the powers of rationality and consciousness are ‘formal’, and are therefore underdetermined as to the ways in which they are physically realised . . . . Or, to put it differently, the same powers of rationality, as formal qualities, could be realised in different material ways. (175)

Davison then turns to Aquinas’s discussions of a body fit for an intellect in ScG, II.90, ST Ia, q. 76, a. 5, and Q. Disp. De Anima, q. 8. He notes that the teleological and hylomorphic “fit” of intellectual soul to body can be read as tantamount to a maximal point of evolutionary convergence—if a biological organism is to support mind, there is an ontological bottleneck where this can occur, namely the human species. Davison suggests, however, that the force of Aquinas’s argument can be redirected: “Aquinas does not so much deny that there could be other rational animals as deny that any such creatures would be fundamentally different from us.” (179) They would, for instance, be under natural law (184). Basing himself on one of the only accurate presentations of Charles De Koninck’s idea of philosophical species that I have seen in print (179n28), Davison suggests that taking “‘species’ here in a philosophical rather than biological sense” is possible (179). This allows him to push back gently on Aquinas’s maximalism. There could be other “bridges” between the angelic realms of created intelligence and the physical cosmos: “the import [of Aquinas’s arguments] may be more to define all rational animals as being of the same fundamental bridging kind, rather than to deny that there could be multiple biological examples.” (181)

Parts I–III fall more under the “Astrobiology” half of the title—Parts IV and V turn to “Christian Doctrine” more explicitly. Part IV, “Christology, Salvation, and Grace,” is the book’s heart. The scope of inquiry Davison maps out as follows. Suppose that there are intelligent alien species; they are either fallen or unfallen. Fallen species, assuming they are not damned outright, might be redeemed through the Incarnation of Christ in human nature, through an additional incarnation in their own species, or redeemed in some other way. An unfallen species, by comparison, might receive an “additional ‘incarnation anyway’,” or be joined in some manner to Christ.

The main assumptions and options from this conceptual map are then explored. For instance, in discussing sin and fallen natures in Chapter 10, Davison notes, following St. Augustine, that the “wider world [is] not changed by sin as to its nature: what changes is the human being.” (199) The real possibility of fallen races elsewhere in the cosmos is considered in view of the fragility of biological constitutions or as tied to the fall of the angels or as falling within the overarching purposes of God. Nor does Davison conclude that a fall is inevitable, as likely as it might appear given “the pressures of nature—of matter and its frailty, and of evolution and the propensities it bakes in.” (207) The possibility of an unfallen state is, indeed, as real for other species as it was for our own.

Another example is in Chapter 17, the consideration of God’s dealings with unfallen races. Is not the entirety of creation “for the sake of the glory of Jesus Christ”? Did he not atone for the sins “of the whole world” (1 John 2:2)? Why is the Incarnation needed or suitable at all?

Behind these various questions lies a divide in emphasis between ‘Incarnation’ and ‘the Incarnation’: whether Incarnation is the central feature of the history and destiny of the cosmos, recurring as a pattern of God coming to dwell with his people wherever they are, hypostatically uniting their nature to himself, or the Incarnation—that God became human in Jesus of Nazareth. In one sense, there may be theological merit in choosing a Person (namely Jesus Christ) rather than something more abstract (a potentially vague ‘Incarnational principle’) as the more elevated emphasis. On the other hand, speaking about the importance of Incarnation (as a principle) turns out to serve the purpose that an emphasis on ‘the Incarnation’ might be taken to stress: it underlines that it would be fitting for all of God's creatures, and not just humans, to be able to turn to a person, rather than an abstract or foreign idea. Beyond that, given that I think there are other reasons for being open to the idea of many Incarnations, . . . it may be possible to uphold ‘the priority of Christ’, but broaden it by saying that the Universe exists for the sake of the full range of Incarnations that God brings about by hypostatic unions, and that the highest good of the Cosmos lies in that. (327–37)

The tentative and probing character of the above argumentation is characteristic of the book. In such hypothetical territory, this is to be counted as a virtue.

Another of the virtues of the discussion in Part IV, especially in Chapters 12–16, is Davison’s exploration of the relationships between categories of necessity, possibility, and suitability (the convenientia of Aquinas or the “behooveliness” of Julian of Norwich). In regard to the topic of multiple incarnations, for instance, Davison notes that “typically, matters of plausibility are set out in the language of possibility, while matters of likelihood are set out in terms of necessity.” (234) Or, when discussing the sufficiency of Christ’s incarnation, Davison is clear, following Aquinas, that it was not absolutely necessary and, once elected, was sufficient for the salvation of many worlds: “The grace of Christ is sufficient not merely for the salvation of some men, but for all the people of the entire world: he is the offering for our sins; and not for ours only, but also for those of the entire world (1 John 2:2), and even for many worlds, if they existed.” (Super Iohan., ch. 3, lect. 6, n. 544) Davison comments in light of this passage as follows:

Speaking of the topic of other Incarnations in terms of suitability relieves us of any need to say what God would or would not do in concrete detail. We do not know what divine dealings with any other life would look like. That need not involve complete agnosticism, however, and in what has just been discussed I have set out what I take to be three characteristics of divine convenientia that we might expect to characterise God's dealings elsewhere, even if we know nothing of the details: that they will be supremely representative of the character of who God is, that they will be artfully accommodated to the created natures involved, and that there will be an equally artful going beyond mere instrumental means, such that the manner by which God deals with things becomes part of the glory of the ends achieved, or indeed part of the end itself. . . . No other Incarnation is necessary. I take this both to be true, but also not to preclude other Incarnations, since there is a largess to the acts of God that goes beyond the minimum necessary to the gloriously fitting. (310, 311)

The possibility of multiple incarnations, then, is defended by distinguishing the person or hypostasis assuming from the nature assumed. (A multitude of incarnations would present no metaphysical impossibility on the part of the Person assuming, I take it, since there is no limit to the mode of union on the part of that Person’s divine nature arising with respect to the nature being assumed.) Throughout, while making his case, Davison navigates theological literature both recent (e.g., Hebblethwaite’s “The Impossibility of Multiple Incarnations”) as well as classic (from the Roman Catholic, Anglican, Calvinist, and Lutheran traditions, alongside the Church Fathers).

The final part of the book, Part V, “Eschatology,” concludes the discussion with questions about the final state of things and the end of the world. What sort of community would be had in such as state? Is the description of paradise as a beatific vision too anthropocentric? How is the end of the world to be understood with respect to many species living in disparate eons and galactic quadrants? Would God, “at some stage, in fact, interrupt and call time on the proceedings”? (358) Well, what would be most fitting? most behoovely?

In one sense, then, Christian theology has the resources it needs to respond to the idea of a cosmos whose end may not come in the history of the Earth. Nonetheless, that would call us to think through something not often considered by theology in its more traditional forms, namely the prospect of a post-human story for the Earth, and for the universe more widely. The Earth will not endure forever, even if time is allowed to roll on. The sun would eventually fail, and expand, destroying our planet. Indeed, there is reason to suppose that humanity would eventually pass away sooner than that, either in outright extinction, or by continuing evolution (or self-adaptation) leading to a species other than human. Some of those options raise significant theological questions, especially for Christology and soteriology. Although provoked by thinking about theology alongside astrobiology, I leave them to be pursued elsewhere, since the consequences are not about astrobiology in themselves, but an Earth, and a Cosmos, after a time of the humans. (359)

An Expanding Theological Universe?

Davison’s treatment of the subject in Astrobiology and Christian Doctrine, while not encyclopedic, is certainly far-ranging and complete in various registers; for instance, in terms of topics and questions, interlocutors across the Christian theologican tradition, and arguments and objections considered, and considerations of science, philosophy, and theology. The book is highly recommended. I propose two topics for readers’ consideration.

First, there are objections on Thomistic grounds to certain points of Davison’s investigation. On the one hand, the book shines as an example of engagement with contemporary issues while learning from the Angelic Doctor (I especially appreciated learning from it about E. L. Mascall’s work). For instance, Davison balances to good effect the principle that theology must be guided by what is “revealed in the Sacred Scripture, in which the Divine Will is made known to us” with the recognition that the categories of what is necessary, possible, or suitable that “the power of God is not limited” to a certain means of action, as “even had sin not existed, God could have become incarnate.” (ST, Ia, q. 1, a. 3, c.) 

On the other hand, one need not be a Thomist of the strict observance to have questions at certain points. For instance, consider the topic of the soul as form. Davison maintains that, in non-human cases of composite substances, there is only a “notional distinction between form and matter” (178), presumably in contrast to a non-notional or real distinction between them. This is not exactly “straightforward hylomorphism” but merely one interpretation of it. Or consider the immateriality of the rational soul. Aquinas holds that rational capacities as such—those arising from the intellect and not, say, the vis cogitativa or the imagination or corporeal memory—cannot be brought into existence by way of material changes or generation. Thus, Davison states that “Aquinas would deny that these capacties are, or could be, the result of a natural process. I am reluctant to go down that road unnecessarily.” (170n5) This reluctance is ambiguous. Is this due to concerns over evolution of the human body as the disposed subject for the human intellect? This seems unlikely. More narrowly, is the reluctance due to Aquinas’s position that “it is impossible for an active power existing in matter to extend its action to the production of an immaterial effect.” (ST, Ia, q. 118, a. 2, c.; see also De Potentia, q. 3, a. 9) Davison also notes that “many theologians today would not agree with Aquinas that reason belongs to the soul operating independently of the brain: that at the apex of rationality, the mind may reason about things supplied to it by the body, but not by means of anything bodily.” (179) Yet not to rebut such a view surely endangers others. Even granting the multiple-realizability of rational animality in diverse biological substructures as necessary conditions, the hesitation on this issue is unnecessary. For Aquinas’s theses about the creation of the immaterial human soul as well as the immaterial operation and subsistence of the human soul are philosophical praeambula central to his theology and stand upon sound principles. Unless, of course, there is some conflict between the immateriality of the soul and such multiple-realizability. Would one have to add the possibility of diverse species of intellectual souls?

Second, there are objections on Catholic grounds to certain points of Davison’s investigation. On the one hand, the book throughout is a model of irenic ecumenical theology that does not avoid taking principled stands. On the other hand, among us separated brethren, can there be a via media on all issues? Are there not certain topics which do not admit of such amelioration? For instance, in his consideration of eschatology, Davison notes that “we find occasional comment that the role that has been attributed to some of the saints in the future state, at least within some varieties of Christian theology and piety, may need to be revisited if the cosmos is widely populated with life: Mary as the Queen of Heaven, for instance, or St. Peter as its gatekeeper.” (346) He continues shortly after:

Turning to Mary, we may do well to set the language of queenship aside, since it is a relative latecomer in Mariology, and not shared even by all Christian traditions that accord the Mother of Jesus particularly high honour. If we were to retain it, we could again stress particularity, with Mary as Queen of redeemed humanity. Queenship, or monarchy more generally, is inherently particular: Elizabeth II was my Queen, and no less so because the USA is a Republic, or because someone in the Netherlands or Norway has a monarch of her own. Other Marian roles and honours are squarely grounded in Mary's role in the economy of salvation. To call her Theotokos, the God-bearer or Mother of God, is an absolute claim, and again not diminished if God also took a different sort of flesh elsewhere. She remains the one who represented humanity at the Annunciation, the one from whom God took human flesh, the chief human agent, alongside Christ, in the drama of redemption. She would remain Madonna: Our Lady. Indeed, that title may be ideally suited for use in a cosmic setting. The shift, if there are other Incarnations, would simply be to say that Mary's response and role belong within the Earthly story, even if there are others. (347)

There is much to say about such a suggestion. First, it is true that Mary as Queen is not embraced by all Christian traditions. However, it must be so embraced by Catholics (see Pius XII, Ad Caeli Reginam). While it is true that monarchy has human particularites about it, to draw on a strategy which Davison employs throughout his book, authority among species of rational animals would seem a universal candidate—would not all such species be political in their own mode, if they also are capable of communication, subject to the moral law, and ordered to God? That is, that role and honor presents no particularity such that it cannot be extended or explicable elsewhere. Furthermore, why is not the case that Mary’s title as queen is squarely grounded in her role in the economy of salvation? Fr. Édouard Hugon argues that “the divine maternity confers an inalienable right to the eternal inheritance, and even to the dominion over all things.” (Mary, Full of Grace, 62) Indeed, is she not queen because she is Christ’s mother, and is not Christ King of the Universe both by natural right and right of conquest through the cross? (See, Pius XI, Quas Primas, n. 13: “A thought that must give us even greater joy and consolation is this that Christ is our King by acquired, as well as by natural right, for he is our Redeemer.”) Fr. George Kirwin, O.M.I., argues that Mary’s queenship is a fulfilment of the Old Testament type of queen-mother, or ‘Gebirah’, the mother of the new king with role, among others, of intercessor. Edward Sri extends this claim into the New Testament. What is more, if Mary’s role as queen is due precisely to her divine maternity—and, granting, for the sake of argument, that just as the uniqueness of Christ as telos of the cosmos accommodates multiple incarnations, so too the uniqueness of Mary as his Mother attains to that same hypostatic order in the plan of divine providence and in the same mode of accommodation—then an honorific of like magnitude would be not merely fitting for but due to the biological mothers of other incarnations in the universe. For it is not inconceivable for there to be multiple queens of the realm in the divine regime. Indeed, such a title and role may be most ideal for the setting of the cosmos, as it would bring supremely unify all species brought to the heavenly homeland.

But the ways of God infinitely exceed what seems fitting to me.

Conclusion

Aquinas, in the Catena on Matthew (ch. 18, lect. 3; as well as on Luke, ch. 15, lect. 1), notes comments of Hilary and Gregory that the ninety-nine sheep of Our Lord’s parable represent angels, while the one lost sheep represents humanity. (See also In Matt., ch. 18, lect. 2, nn. 1511–12) Elsewhere, Aquinas argues that angels exceed in multitude even material substances, “since it is the perfection of the universe that God chiefly intends in the creation of things, the more perfect some things are, in so much greater an excess are they created by God.” (ST, Ia, q. 50, a. 3, c.) Why is it not the case the arguments about such divine largess and redemptive concern may be reapplied, as it were in fractal, to the physical cosmos? For embodied intellectual creatures are also perfections of the cosmos. The speculative leisure of sapiential theology ought to revel in its contemplation of the Creator’s largess, to marvel at the divine fittingness of things, even while grounded in the intelligibility of the necessary and the possible. Such is the spirit of Prof. Andrew Davison’s excellent book, and such is my reason for recommending it.