1.1 Rationale for religious naturalism

Although RN is characterized by diversity and, to some extent, disunity, it is possible to identify common arguments in favour of this religious option. There are those who argue that the supernaturalism of classical theism has been rendered untenable due to the advancements of modern science (see Theology and Science). A second argument is that RN is better suited in terms of motivating appropriate ecological behaviour and reverence towards the natural world compared to supernaturalism which, according to these critics, devalue nature by attributing ultimate value to a supernatural being/realm.

Loyal Rue encapsulates the sentiment of many religious naturalists in terms of the epistemological shift with the arrival of modern science: ‘[w]hereas we once explained nature in personal terms, we now explain personal reality in natural terms’ (2005: 317). The explanatory arrow has changed direction, as we now seek to explain meaning, values, morality, consciousness, and other higher-level phenomena through the basic categories of the natural and physical sciences. It should be noted, however, that whereas Rue earlier adopted a form of scientific materialism – suggesting that everything that happens is contingent on purely material categories – later writings have moved towards a softer version of emergent naturalism, which more clearly stresses the irreducibility and existence of meaning and morality (cf. 2005: 14–15; 2011: 51–54).

Charley Hardwick is equally adamant about how contemporary science informs his, in this case, physicalized articulation of Christian theology. More specifically, he suggests that the impressive progress of the natural sciences has rendered traditional religion explanatorily obsolete. It is possible to account for all that exists without invoking a supernatural being with intentions and ideas. As Hardwick says, ‘[a]ll existence, all order, and all action can be accounted for without recourse to the operation of intelligent purpose’ (1996: 16).

Gordon Kaufman stresses the incoherence of supernaturalism, and especially the notion of a ‘Creator God’, due to the insights delivered by modern cosmology and evolutionary theory. The notion of a creator God implies a view of a conscious being that brought the natural order into existence; suggesting that mind is prior to matter. Yet, according to evolutionary theory, the opposite is true, given that the organization of matter brought mind and conscious beings into existence over the course of billions of years of evolutionary development (Kaufman 2007: 917). In this sense, an evolutionary view of the world clashes with the fundamental convictions of Christian theology and other theistic traditions.

In his book Religion, Science and Naturalism (1996), Willem Drees outlines three ways in which science significantly impacts Christian theology. First, given that science, and fundamental physics in particular, seems to reveal a world that is constituted by a ‘tightly knit web of processes described by laws’, this renders it difficult to claim that God interacts with humanity and the created order, or performs miracles (Drees 1996: 92). Second, Drees argues that science, due to its impressive success, warrants a metaphysically realist understanding. Yet, when one turns to the domain of theology, there is a lack of progress as there are still significant disagreements regarding the nature of God, divine agency, and so on. Thus, we are not justified in asserting that Christian theology describes an ontologically independent reality. Drees’ third argument centres on the untenability of dualism given what we know about the neurological makeup of human beings and the causal structure of the universe. That is, ‘[a] dualism of matter and non-physical substances is unlikely, since the relation between the mental and the physical is very intimate’ (Drees 1996: 188).

Another common argument for RN considers the current ecological challenges facing humanity: climate change, reduced ozone layer, pollution, loss of biodiversity, ocean acidification, and so on. The reasoning here is that traditional religions have fostered a destructive relationship with the natural order, whereby the earth and its resources are only valuable insofar as they are useful to human beings. On this view, the anthropocentrism of Western Christendom is uniquely responsible for the ecological crisis. Gordon Kaufman suggests, for example, that Christian theology has been too human-centred, and that the human-God relationship has ‘obscure[d] and dilute[d] […] ecological ways of thinking about our human place in the world’ (2004: 41).

Karl Peters traces the problem back to Christianity’s accommodation of Greek philosophy, and especially the posed dualism between spirit and matter (2002: 103). Such a dualism separates good from evil, the transcendent from the natural, and leads to a view of the world according to which the natural world is identified with evil ‘and says that we must escape from or conquer the material world’ (Peters 2002: 102).

Although some religious naturalists maintain that traditional religions may still be able to offer robust and effective responses to the ecological crisis (see Goodenough 2023; 1998), others are more sceptical. Rue, for example, remarks that such a response requires unity, but that the odds are stacked against such efforts given the influence of eco-critical conservative voices that understand the growing ecological concerns as a manifestation of a broadening secular outlook (2005: 354–355). Hence, Rue suggests that a new and naturalistic root metaphor is needed to renew our relationship to nature.

In Sacred Nature, Jerome Stone frames the role of a religious naturalist as a public ecotheologian; a public intellectual ‘who uses recognized images of transcendence, such as “sacred,” “spirit,” or “creation,” in addressing major public issues’ (2017: 133). On this account, then, the naturalistic public theologian uses purely naturalistic images to address ongoing public challenges (see Michael Hogue’s discussion of the ethical orientation of RN in 2010).

In the same volume, Stone outlines a third argument often considered in favour of religious naturalism, namely the pragmatic benefits of a fully naturalistic spirituality/religiosity. Compared to Abrahamic theism, a naturalist does ‘not have to wonder why God is allowing bad things to happen’ or ‘worry about the conflicts about science and religion’ (2017: 3). And living as a ‘religious naturalist means you do not have to live in a totally alien world’ (2017: 3, original emphasis). Karl Peters stresses, in a similar vein, the spiritual benefits of RN, suggesting that if God is understood as a transcendent being, then God will be difficult to relate to. If we, in contrast, take ‘God’ to be a creative process, immanent in the natural order, that we as natural human beings can participate in, then we can relate more closely to God (2002: 39). God would no longer be ‘an absentee landlord’ that left the scene after the initial events of creation, but a partner in the co-creation of the world.

1.2 Historical predecessors

Earlier attempts at developing theories of naturalized spirituality may be found in the work of George Santanaya, Henry Nelson Wieman, and John Dewey (Stone 2008: 4). Santanaya, a Spanish-American philosopher (1863–1953), critiqued an ontological understanding of Christian beliefs regarding the nature of God, but acknowledged their value in the life of human beings (2008: 21). Yet, to consider such value merely in terms of practical usefulness, or by the ‘benefits the populace may derive from it’, would be to misunderstand the nature and function of religious discourse (Ratner 1923: 463). As Willard E. Arnett remarks, religion has a poetic function for Santayana: ‘Whatever ideas, ideals, or figments may be expressed in religion – and poetry – are thoroughly human and must be understood in terms of their genesis and function, even if they cannot be accepted as indicative of the nature of the universe outside man’s experience’ (1956: 775). In this way, religious propositions and beliefs must refer to this world and the challenges facing humanity; an emphasis that bears a strong resemblance to the proposals of many religious naturalists.

Henry Nelson Wieman’s understanding of God as creativity has exerted a notable influence on several religious naturalists – Gordon Kaufman and Karl Peters in particular. According to Wieman, and in a similar vein to Santayana, we must reject ‘the transcendental affirmation in the Jewish Christian tradition of a creative god who not only works in history but resides beyond history’ (2008: 6). A stern critic of Barthian Neo-orthodoxy, Wieman forcefully argued against what he perceived as a ‘deprecation of reason in theological thought’ (Heppler 2018: 50). At the same time, he voiced concerns about the increasing power of science and technology of his time that he considered a real threat to humanity, exemplified most acutely in the development of the atomic bomb. In Wieman’s Creative Naturalism, ‘the only creative God we recognize is the creative event itself’ (2008: 6; Heppler 2018: 53), and his naturalistic soteriology implies that ‘the only things that exist or can accomplish anything are events, relations, and qualities’ (Stone 2008: 85).

In contrast to Wieman’s attempt at locating God in the creativity of the world, Bernard Loomer’s naturalistic theology ‘identified God with the totality of the world’ (Stone 2011: 209). In his essay ‘The Size of God’ (1987), Loomer situates his position in relation to Wieman’s attempt at ‘defining God as one process among others’ and Whitehead’s theology according to which there is an ontological separation between God and creativity. Although Loomer’s proposal departs significantly from Whitehead’s panentheism, it is also greatly indebted to his process metaphysics, whereby ‘becomingness’ is framed in a relational and non-substantive manner and there is ‘nothing beyond processive actualities’ (1987: 27). This emphasis on interdependence and relationships at all levels was central to Loomer’s notion of ‘web of life’ through which God, as the ‘interconnected totality’, operates (1987: 41; see Stone 2008: 96–100).

This disagreement between Wieman and Loomer as to whether nature as a whole should be considered religiously significant will be further explored in light of Donald Crosby’s ‘Religion of Nature’ (2002; section 3.3).

As explored in the previous section, a common argument in favour of a naturalistic spirituality pertains to the seeming practical benefits that this yields for our ecological behaviour and spiritual life. Here we can see the influence of John Dewey’s pragmatic religious naturalism, which sought to separate ‘the religious’ from established religious institutions and metaphysical schema. From this Deweyan perspective, the religious impulse ‘must be liberated from the supernatural commitments of actual historical religions, from dogmas and doctrines’ (Pihlström 2010: 215). According to Dewey, who articulates this standpoint most clearly in A Common Faith (1934), it is not merely possible to distinguish ‘the religious’ from the metaphysical systems of established religious traditions, but it is our duty to do so given that the realist commitments of such religions ‘prevent genuine religious experiences from coming to consciousness’ (Pihlström 2010: 215).

Two other notable predecessors should be mentioned, especially due to their clear monistic and anti-supernaturalist commitments; the Jewish philosopher Baruch Spinoza and the existentialist theologian Paul Tillich.

On Spinozistic pantheism, only God/Nature exists, as a necessarily existing substance, yet there is some disagreement about this religious outlook. For some, Spinoza simply equated God with the natural domain, which would bring this view significantly close to contemporary religious naturalism. For others, however, Spinoza differentiated between the active and passive aspects of nature, that is, between natura naturans (nature nurturing) and natura naturata (nature natured) (Wheeler 2018: 110). It has been argued that Spinoza primarily identified God with natura naturans, namely that which brought the natural world into existence. Such a distinction has similarly been expressed by some religious naturalists, and especially those – including Karl Peters, Gordon Kaufman, and Stuart Kauffman – who understand God to refer to the creative processes of nature. At the same time, the similarities between pantheism and RN should not be overstated given that Spinoza forcefully stated that, in contrast to the conviction of many religious naturalists, nature is not sacred and is not an appropriate object of religious devotion and reverence (see Leidenhag 2021: 12–13).

As with many religious naturalists, Paul Tillich’s ambition was to navigate towards a non-supernaturalist account of God. On this view, God was not a being, existing independently of the cosmos, but the very ground of being itself (see his three-volume systematic theology, 1952; 1957; 1963). Wesley Wildman identifies several significant overlaps between Tillich’s theology and RN (2009: 19–21). For example, he largely agreed with the naturalist critique of supernaturalism, and suggested that it ultimately collapsed into idolatry. Yet, he also took issue with those materialistic understandings of naturalism that seemingly eliminated the religious dimensions of reality entirely. Tillich, furthermore, did not seek to accommodate God’s existence within the categories of the natural/physical sciences, but suggested that ‘God as the ground of being infinitely transcends that of which he is the ground’ (1957: 7, quoted in Stone 2008: 10). Tillich’s religious ontology sought to go beyond both supernaturalism and the naturalism of his time.

Lastly, we should briefly note the significance of Alfred North Whitehead’s process metaphysics for the development and trajectory of religious naturalism, before exploring this in the next section from the perspective of panentheistic proposals. Donald Crosby’s Religion of Nature takes its cue from Whitehead’s philosophy of nature, especially the relational aspect of process metaphysics and the ways in which it grounds values in natural facts (2002: 65–66). Whitehead’s rejection of substance metaphysics with the notion of immutable individual subjects in favour of an ontology of processes, relations, and a creative universe (Zycinski 1989) form, likewise, an important backdrop against which to understand the proposals of several religious naturalists. In particular, Whitehead’s notion of ‘creativity’ is an important precursor to the religious proposals of Peters (2002), Kaufman (2004), and Kauffman (2008).

1.3 Neighbouring perspectives

Let us pick up where section 1.2 left off, with process theology. Process theologians typically self-identify as naturalists, and thus see themselves as bridging naturalism and religion. David Ray Griffin, in Two Great Truths (2004), seeks to show how a moderate, non-materialistic naturalism can be reconciled with the panentheistic vision of Alfred North Whitehead. On this panentheism, which seeks to emphasize the immanence of God, divine activity is framed in a naturalistic manner, such that whatever God accomplishes in the natural order occurs solely through the configuration of natural/physical processes. Some panentheists picture the universe as the body of God, ‘through with God lives his or her life, as we live our lives through our bodies’ (Stenmark 2013: 513; see Peacocke 2004). According to the physicist-theologian Arthur Peacocke (not a process theist per se), the world is in some sense ‘in God’, while God is more than the totality of the world. God’s interaction with the world, then, is framed in accordance with systems theory:

Thus, it is proposed, mediated by such whole-part influences on the world-as-a-whole (as a System-of-systems) and thereby on its constituents, God could cause particular events and patterns of events to occur that express God’s intentions. (Peacocke 2007: 45, original emphasis)

Given its opposition to supernaturalism, would it be possible to understand process theism, and panentheism more generally, as a genus of religious naturalism? The religious naturalist Jerome Stone answers negatively: ‘Immanentist yes, naturalist no’ (2008: 8; cf. 2017: 11). Given that process theism and similar panentheistic outlooks still take God to be ontologically distinct from the universe, while being immanently present in it, it seems difficult to frame such views as subsets of religious naturalism.

Religious naturalists, as opposed to process theists, emphasize the primacy of the physical. Whatever exists arose from a physical substrate, whether this be framed in a purely reductive or emergentist fashion. Here it is worth considering another neighbouring perspective, namely Samuel Alexander’s emergent theism which preserves the primacy of the physical while acknowledging the reality of God (1920). That is, God, like any other thing in the inventory of what exists, emerged naturally through the order and disorder of physical reality. God is, thus, both transcendent and completely dependent on the physical universe. However, given the ontological reality of God, this would perhaps push religious naturalism too far in the direction of theism, which would threaten the naturalist conviction that the world is constituted by a causal web, governed by and describable in terms of natural laws.

Another demarcation issue arises when we consider religious humanism. Take, for example, William Murry’s book Reason and Reverence: Religious Humanism for the 21st Century (2007). In a similar vein to religious naturalists, Murry seeks to show how values, meaning, morality, and reverence for the workings of the natural realm are possible without invoking a transcendent or supernatural realm. In this way, Murry’s articulation of humanism differs from secular humanism, as it encourages positive responses to issues of ultimate meaning and the ‘cosmic question’ (see Stenmark’s discussion, 2013: 543). Jerome Stone previously drew a sharp line between RN and humanism but recognizes that a Murry-type religious humanism can appropriately be considered as belonging to the wider family of religious naturalism (Stone 2008: 8; cf. Stone 1999). One could make the argument that given Murry’s reluctance to employ God-language it differs from RN, but as was noted earlier, not all proponents of religious naturalism seek to retain theistic language.

In Black Lives and Sacred Humanity (2016; see also Wayne White 2018), Carol Wayne White explores the interconnection between religious naturalism and humanism in her attempt to offer an account of ‘sacred humanity’ within the context of African American religiosity. This anthropological notion, which draws heavily on the work of Rue, Goodenough, and Kauffman, emphasizes, through a communal ontology (2016: 35), human beings as ‘social organisms’. White recognizes the seeming strangeness of ‘deriving an African American religiosity based on an understanding of humans as natural processes’ (2016: 37), but suggests that such a view, rather than inviting a reductionist anthropology, allows us to sacralize human existence and ‘honor our finite, stubborn materiality’ (2016: 45). Following Loyal Rue’s functionalist interpretation of religion (2005), White demonstrates the emancipatory function of ‘sacred humanity’ by allowing African Americans to humanize ‘their existence in the face of dehumanizing gestures and tactics by dominant white culture’ (2016: 34). When considering White’s project, we can see more clearly how the line is blurred between religious naturalism and humanism in the way that she develops humanism against the background of a naturalistic ontology.

As noted in section 1.1, a common argument in favour of religious naturalism is that it is better situated to provide effective responses to the ecological crisis. If God is brought all the way down to the natural domain, we are more likely to value nature and act in ways that would benefit our fragile eco-systems. Given the nature-centredness of RN, what about ‘nature religions’? The term ‘nature religions’ connotes the idea that nature is sacred and worthy of reverent care. This notion is a core part ‘to the identities of a number of groups whose participants consider themselves to be engaged in what they also sometimes call nature religion’ (Taylor 2006: 598). The term covers a wide range of perspectives, such as Indigenous traditions, paganism, and New Age spirituality. Indeed, in a similar way to religious naturalists, practitioners of nature religions argue or suggest that an eco-ethical orientation flows from placing nature at the centre of one’s spiritual focus (Leidenhag 2021: 15). Despite the obvious overlaps between religious naturalism and nature religions, it remains the case that the latter typically involves beliefs in gods, spirits, and a wide range of animist ideas. Thus, despite both being strongly committed to increased ecological awareness, RN is also more clearly concerned with harmonizing religion/spirituality with the major theories of the natural sciences (as naturalistically conceived).

2.1 Physicalism and emergent naturalism

Let us start with Willem Drees’ physicalist stance. Drees has objected to being labelled a ‘religious naturalist’, or a philosophical naturalist for that matter, preferring instead the softer notion of a ‘science-inspired naturalism’, which recognizes our intellectual and moral obligation to ‘draw upon the best available knowledge to serve each other and counter unnecessary suffering’ (2020: 32). A science-inspired naturalist could be a philosophical naturalist, or religious naturalist, ‘but need not be’ (Drees 2020: 34). Nevertheless, his articulation of physicalism is most helpful in terms of fleshing out the ontological commitments of this framework. Drees concedes that his position goes beyond the deliverances of the sciences, but he insists nevertheless that he offers a ‘low-level metaphysics’ because it stays close to the insights offered by the sciences (1996: 11). The ontology and epistemology of Drees’ physicalism are summed up in two main claims: first, that ‘all entities are made up of the same constituents’ (constitutive reductionism), and second that ‘physics offers us the best available description of these constituents’ (physics postulate) (1996: 14). Yet, while suggesting that physics is best placed to describe reality at its finest level of analysis, Drees is careful to stress that some questions ultimately escape the reach of science, and that some phenomena may require concepts and vocabulary beyond that of the language of fundamental physics.

The Christian naturalism of Charley Hardwick espouses something quite similar. In several writings (1996; 2001; 2003), Hardwick has emphasized how physicalism places ‘constraints’ on any articulation of religious naturalism. Drawing on the philosopher John Post’s book The Faces of Existence (2007, first published 1987), Hardwick has formulated a ‘physicalist version of naturalism because it is naturalism’s most austere form and thereby articulates the constraints imposed on religion and theology with the fullest explicitness’ (Hardwick 2001: 194). According to this physicalism, ‘only the basic objects of mathematical physics exists and […] everything at a higher or more complex level can occur only if there is corresponding occurrence at the level of physics’ (1996: 33). Thus, Hardwick claims in a similar vein to Drees that ‘all truth is determined at the level of physics’ (1996: 36), but adds a deterministic element to his ontology that renders all higher-level phenomena causally determined by lower-level physical events.

We will now turn to emergence theory, which can be considered a neighbouring but ontologically less restrictive perspective than the physicalism of Drees and Hardwick. Emergence theory, although it can be construed in multiple ways, typically encompasses some of the following claims about nature and physical phenomena. First, reality, as opposed to the reductive efforts of physicalism, is layered, such that ‘reality is divided into a number of distinct levels of order’ (Kauffman 2006: 503). Higher-level properties – such as meaning, normativity, values, consciousness, free will, etc. – emerge due to the interactions between constituents found at lower levels. Ursula Goodenough suggests this when she writes that the interaction between physical properties generates ‘Something Else from Nothing But’: a water molecule is nothing but an oxygen atom and two hydrogen atoms bonded together, but under freezing conditions they can generate ‘the something-else called the snowflake’ (Goodenough 2023: 25; cf. 2003: 802). Second, these higher-level properties are epistemologically irreducible to lower-level constituents, or to the level of fundamental physics. Loyal Rue has suggested that meaning itself is one such irreducible feature of reality (2011), which is rendered intelligible by the fact that teleological language is indispensable to make sense of evolution; natural selection offers excellent insights into specific modifications in living systems, but it does not provide a sufficient explanation of life itself. That is, ‘[e]volutionary theory assumes the teleological nature of living systems’ (2011: 58, original emphasis). Gordon Kaufman echoes the view that we encounter an epistemological limit regarding emergent phenomena when he writes, ‘We do not (and may never be able to?) understand the mystery of how greater and more complex things can come out of simpler and lesser things’ (2004: 92).

The first two statements sum up what is often referred to as weak emergence (see Chalmers 2006). However, a third statement takes us towards strong emergence, according to which novel properties enter reality through the creativity of nature. According to Donald Crosby, ‘[n]ew levels of organization bring into existence new kinds of being’ (2010: 198). Such novelty is often framed in terms of causal effectiveness. Typically, thinkers who are inclined towards strong emergence maintain that an emergent property must play some sort of causal role in order to be considered a genuine feature of reality, and such a causal role is often understood in terms of downward causation. This notion suggests that a higher-level entity or emergent phenomenon (say consciousness) manifests causal powers so that it affects its constituents, or the whole causally affects its parts (the body). This goes contrary to Hardwick’s determinism whereby all causal work is ultimately reducible to the laws of fundamental physics.

This short discussion serves to highlight the general backdrop against which Christian religious naturalists articulate their views on God, soteriology, and Christology, discussed in more detail below.

2.2 The nature of God

Here we will begin with Charley Hardwick’s Christian physicalism, and then explore the emergentist theologies of Karl Peters and Gordon Kaufman. The ‘constraints’ of Christian physicalism become evident when we look at Hardwick’s theological endeavour to understand the nature of God. Hardwick is clear about the implications of his wider metaphysical commitments; namely that ‘“God” is nowhere to be found in a physicalist inventory of what exists’ (1996: 51). If the term ‘God’ lacks objective reference, if we take the background to be theological realism (Trigg 1998; Moore 2003), then what is the purpose of God-language within the context of Christian theology? Is ‘God’ simply superfluous? Hardwick answers in the negative by asserting that the statement ‘God exists’ can still be objectively true on a physicalist reading of Christian discourse (1996: 115). Hardwick’s solution lies in the resources of existentialism.

First, he turns to the ‘empirical theology’ of Henry Nelson Wieman (discussed in section 1.2), according to which the question of God is not about whether a being, with certain omni-attributes, exists. Instead this question concerns ‘our orientation to “the source of human good”’ (1996: 116). Hence, Wieman interprets theological statements existentially; as statements about our self-understanding and orientation to the world. This view, however, does not necessarily force us down the relativist route, given that it is still possible to critique and falsify such self-understandings and ‘valuational stances’ (1996: 116).

A second crucial interlocutor for Hardwick is Rudolf Bultmann and his ambition to link existential assertions about God to grace (we will return to this in section 2.3). Bultmann’s project of demythologization and existentialist understanding entail that ‘[t]heology’s task is the interpretation of faith, and faith is nothing other than existential self-understanding’ (Hardwick 1996: 83). According to Bultmann, the enemy of real faith is ‘myth’, which he understands as distorting faith by viewing faith as an objective state of affairs that can be either true or false. Instead, ‘faith is a mode of existing’ (Hardwick 1996: 86) and the statement ‘God exists’ expresses an existentially grounded valuational stance; or a ‘seeing-as’ (Hardwick 1996: 158–206).

Drawing together Wieman and Bultmann, Hardwick’s soteriology centres on the notion of Christianity as a seeing-as; that is, as a transformative event (Wieman) enabled by a faith that is constituted by an ‘openness to the future’ (Bultmann). Hence, a physicalist re-interpretation of Christianity, based on a thoroughgoing valuation theism, ‘becomes possible when Rudolf Bultmann’s […] method of existentialist interpretation is wedded to Henry Nelson Wieman’s naturalist conception of God’ (Hardwick 2003: 111).

Both Gordon Kaufman and Karl Peters retain a form of religious realism but construe the religious reference as the inherent creativity of the natural order. However, they both agree with Hardwick that the statement ‘God exists’ can no longer, due to the advancements of the natural sciences, be understood as referring to a transcendent being. Kaufman’s earlier work – including The Theological Imagination: Constructing the Concept of God (1981) and In Face of Mystery (1993) – was heavily influenced by the philosophical scepticism of Immanuel Kant, whereby a direct and immediate experience of reality is impossible. Inspired by Kant, Kaufman arrived at the conclusion that ‘talk about experience of God involves what philosophers call a “category mistake”’ (Kaufman 2001: 9, original emphasis). God is not the sort of thing that can be directly experienced and, following the Kantian logic, God can only be understood as an imaginative construct of the mind. Adopting Kant’s epistemology, Kaufman makes a distinction between the ‘available referent’ and the ‘real referent’. The former refers to ‘a particular imaginative construct […] that bears significantly on human life’ (1972: 85), whereas the latter refers to God in God-self, which lies beyond the limitations of our cognitive faculties (another notable employment of this distinction can be found in Hick 2004).

Whereas this earlier work of Kaufman can be considered a form of apophatic theology, it is with the book In the beginning…Creativity (2004) that he takes a decisive step in the direction of naturalistic metaphysics. Kant, although still important, is no longer forming the theoretical background to Kaufman’s theological project. Instead, it is the evolutionary narrative that takes centre stage and sets the boundaries for God-talk. This ‘biohistorical’ framework considers the long evolutionary history of human nature, and provides new opportunities for reimagining the function of the symbol of ‘God’, breaking away from those Western religious traditions that have used the symbol of God to sanction an anthropocentric view of reality (Kaufman 2003).

We employ the symbol of God to remind ourselves to more fully participate in the mystery that is continuously being manifested in the world (Kaufman 2004: 76, 85, 100). Hence, ‘God’ signifies the novel and mysterious phenomena that are brought into existence through the complex workings of the evolutionary process. This mystery is also referred to as ‘serendipitous creativity’, which designates that the universe is not a static or ‘permanent structure, but rather as constituted by (a) ongoing cosmic serendipitous creativity that (b) manifests itself through trajectories of various sorts working themselves out in longer and shorter stretches of time’ (2004: 45–46).

In a similar way to Kaufman, Karl Peters is committed to transforming the Christian tradition from within by utilizing naturalistic insights regarding the natural order, ecology, and the function of religion. Peters, furthermore, follows the tradition of ‘empirical theology’, which states that the adequacy of religious beliefs must be tested against human experience. Thus, given this epistemological principle, supernaturalistic depictions of God and the Divine must be rejected as they do not fall within the purview of human experiences. This line of reasoning is greatly influenced by Ralph Wendel Burhoe, who sought to show how God can be ‘understood in terms of function and systems’ (Peters 1998: 314). Indeed, Burhoe made it possible for Peters to ‘formulate a theology that was in accord with scientific theories, scientific methods, and a scientific view of the world’ (1998: 318).

What notion, then, of God is viable within the emerging scientific worldview? Peters, employing Kaufman’s idea of serendipitous creativity, suggests that this concept ‘points to a system, the parts of which work together in unpredictable ways to create such things as new life, new truth, and new community’ (Peters 2002: 35). By understanding God as the universal creative process, we can gain a deeper appreciation of our place in the cosmos. Here Peter adds another interlocutor to his project: Charles Sanders Pierce. The pragmatism of Pierce suggests that we judge a ‘concept’s effectiveness in shaping behaviours that help people to ever-greater richness of experienced value’ (Peters 1997: 483). It is the practical efficacy of a theory or concept that determines its relative truth-value, and given that Peters elevates ecological stability to the desired pragmatic goal, our God-concepts are regulated and shaped by this goal.

2.3 Soteriology and Christology

Having outlined Charley Hardwick’s physicalist ontology and his construal of Christian faith as a ‘seeing-as’, we are in a better position to describe the soteriological and christological implications of an existentialist reading of the grammar of theology. Here Hardwick consults a fellow existentialist thinker, Schubert Ogden, who defined the content of salvation as our ‘original possibility of authentic existence’ (Hardwick 1996: 116). This focus on ‘authentic experience’ necessarily invokes accompanying theological ideas of sin and grace, given that our current condition is a ‘“fallen one” in which this possibility [of authentic experience] cannot be grasped directly’ (1996: 117). But how do we understand ‘fallenness’ without introducing concepts and ideas that would be foreign or antithetical to physicalism? Hardwick turns again to Bultmann, and especially his multifaceted hermeneutical engagement with the New Testament. Briefly put, Bultmann interprets Paul’s condition of sinfulness as ‘wilfulness’, namely the human orientation to seize control over the final conditions of one’s life, clearly expressed in Paul’s condemnation of the Gnostic pursuit of wisdom. As the human condition, or being-in-the-world, is plagued by anxiety and thrownness (the feeling of being thrown into existence), it is possible for Bultmann to make sense of wilfulness as constitutive of our fallen state. Moving from wilfulness to experiencing reality authentically means understanding existence as a gift, as exemplified by Paul’s question to the Corinthians (Hardwick 1996: 120): ‘What have you that you did not receive? If then you received it, why do you boast, as if it were not a gift?’ (1 Cor 4:7). Thus, existentially understood, ‘“receiving one’s life as a gift” is identical with radically opening oneself to the future, and the latter is the existential content of God’ (Hardwick 1996: 121). God-language is not necessary to attain this disposition of openness to the future, ‘but does provide the best account of it’ (Stone 2008: 146).

Where does Christ figure in this physicalist-existentialist accommodation of Christian faith? Here Hardwick builds on Ogden’s The Point of Christology (1982) and its attempt to sidestep concerns of both traditional and revisionist accounts of Christology by focusing on, as the title reveals, the function or point of christological theories. Traditional and revisionist accounts, despite their obvious differences, are united in their effort to understand who Jesus is, but Hardwick through Ogden’s existentialist-historical approach suggests a shift in concern towards the meaning of Jesus for us: ‘In effect, the question about Jesus is about Jesus’s meaning or significance for us’ (Hardwick 1996: 216). According to an existentialist reading, the life of Jesus demonstrates existence in freedom and liberated existence (Hardwick 1996: 233). Although Hardwick, in line with Ogden’s approach, downplays the historical pursuit of the real Jesus Christ, he nevertheless emphasizes the historicity and necessity of the crucifixion, which he deems ‘crucial for the release of this process’ (1996: 247); that is, as a pointer towards the possibility of an openness towards the future.

Kaufman shares Hardwick’s sentiment that salvation pertains to the here and now. More specifically, on his proposed biohistorical naturalism, salvation ‘is that which makes possible escape from or overcoming the powers of evil’ (Kaufman 1981: 167), whereby evil refers to those forces that inhibit human well-being and threaten the survival and flourishing of ecosystems. Moreover, the creativity of nature – the mysterious coming into being of novel realities – gives us reason to hope, according to Kaufman:

It is a creativity manifest on all sides around us and present in and with our own human creativity. We humans are deeply indebted to this creativity that – through a long, precarious passage – has brought our human trajectory (and us along with it) into being. This realization gives a basis for the hope that our trajectory – despite all failures in past and present – might continue on toward a more humane and ecologically sustainable world. (Kaufman 2010: 90)

Christology plays a key part in this soteriological schema. Kaufman acknowledges that a rethinking of Christ is necessary in light of the view of God as serendipitous creativity, as opposed to the traditional attributes of Lord, Father, and Creator. On Kaufman’s reading of New Testament texts (2 Cor 5:17; Col 1:13, 1:15–16; John 1:14), Jesus is portrayed as the ‘image […] of what we have spoken of as the mysterious serendipitous creativity at work throughout the world’ (Kaufman 1993: 384). As part of this christological rearticulation, Kaufman seeks to show how the incarnation does not connote God’s unique presence in the man Jesus, but that Jesus expresses the divine creativity that is unfolding throughout the cosmological, biological, and cultural domains – referring to 1 Pet 1:20. This ‘wider Christology’ – drawing on Gal 3:28 – places emphasis, not on the supernatural and specific presence of God in Christ, but on how the life of Jesus imaged the possibility of an ‘inclusive egalitarian community’ (Kaufman 1993: 396).

The book Jesus and Creativity (2010) pursues this theological motif, but situates it explicitly within a naturalistic metaphysics, showing, again, how Kaufman moved from an apophatic theology to accommodating theological doctrines within a biohistorical naturalism. Jesus provides a challenging norm for what it means to be human, providing a ‘defining paradigm’ for how humans can participate in ‘the new communal order of reconciliation, peace, and love’ (2010: 33, 25), thereby exemplifying the creativity of the world. Yet, this paradigm is not sanctioned by supernatural authority as we need to decide as to whether we want to employ this Jesus-model in our own lives (here Kaufman’s reasoning bears some resemblance to the existentialism of Hardwick). Kaufman emphasizes that not only does Jesus exemplify the mysterious, unpredictable, creativity of the universe, but his life can shed light on and inform our understanding of God as creativity (Kaufman 2010: 50–56).

As mentioned earlier, Peters’ Christian naturalism is deeply influenced by the work of Kaufman. Taking an evolutionary approach, he depicts salvation as the process of ‘restoring and maintaining well-being or functioning well’ (Peters 2012: 843). On a systems-relational approach (inspired by Burhoe), which assumes a view of humans as social creatures, Peters suggests that the ‘saving transformation is from poorer function in a less harmonious manner to more harmonious and mutually enhancing relationships’, thus enabling the emergence of mutually supportive communities that can further human wholeness in a natural world (2007: 55, 56).

In Christian Naturalism (2022), Peters unpacks his view of Jesus and atonement theory in more detail. He briefly elaborates on the substitutionary theory of atonement, but suggests (a) that it assumes a view of God as a personal being that is difficult to maintain in a scientific-naturalist worldview; (b) that the sacrificial theme was surprisingly absent – for example in Christian art – until the ninth century when Charlemagne conquered the Saxons in northern Germany (2022: 83). Instead, Peters finds inspiration in Abelard’s moral influence theory of the atonement, suggesting both its compatibility with a naturalistic and emergentist view of nature and its ability to ground Christian practices (more on this in the next section). The Jesus Seminar member and New Testament scholar Marcus Borg (1942–2015) exerted significant influence on Peters’ understanding of salvation and of Jesus as a social revolutionary (Peters 2012: 834; 2022: 92–93).

2.4 Community and practices

This section will briefly point towards communities and distinctive practices within religious and Christian naturalism, a relatively understudied research area. Although religious/Christian naturalism may not be definable as a separate denomination, some denominational contexts seem especially hospitable to this religious perspective. This was remarked by Demian Wheeler in an address to the First Unitarian Society (2017), in which he sought to enforce the links between Unitarian Universalism and religious naturalism. Indeed, he noted that such links already exist, as demonstrated by the UURN – The Unitarian Universalist Religious Naturalists – founded in 2004. These links should not come as a surprise given that many of the key themes of both Unitarian Universalism and religious naturalism can be traced back to the emergence of American theological liberalism. As pointed out by Todd Macalister, given the sheer limit in number of naturalist organizations, many religious naturalists are active members of Christian, Jewish, Buddhist, and other established groups (2021: 1035).

Religious naturalists have also formed online communities, such as the Religious Naturalist Association, established in 2014 by Michael Cavanaugh. The goals are (1) ‘to create a worldwide “home” for those of us who self-identify as religious naturalists’ and (2) ‘to encourage the development and spread the awareness of a religious naturalist orientation’ (Goodenough 2018: 310). The association hosts a separate Facebook group, a Google Groups discussion forum, and a specific group for practicing and non-practicing clergy in traditional theological milieus. The association intentionally opted for religious naturalists instead of naturalism as the latter may communicate the idea of clearly definable and set doctrines, which may contradict the big-tent ambition of this group. Another notable group is the Spiritual Naturalist Society (https://www.snsociety.org/), which seeks to raise awareness about spiritual naturalist thought and practice. It publishes articles and supports local chapters that host in-person discussion groups and events relating to the spiritual potential of a naturalistic outlook. Its advisory board features influential thinkers, such as Donald Crosby and Jerome Stone.

What sort of practices are available to the religious naturalists? Eric Steinhart has suggested several strategies for how religious naturalists ‘can adopt the practices of theistic religions by naturalizing them’ (2018: 342). Given the nature-centeredness of this religious perspective, one may wonder if ‘ecological rituals’ – as practised by Wiccans, Druids, and Catholic Green Sisters – may be seen as attractive and appropriate forms of religious expression. As Steinhart remarks, religious naturalists have seemingly shown fairly little interest in this. This may be due to the differences in ontologies – recall section 1.3 and the supernaturalist and animist ideas of ‘nature religions’. One may also wonder whether the recent resurgence in Stoic philosophy and rituals can provide additional resources to religious naturalism given that Stoicism seems to mediate a materialist view of the human body (Steinhart 2018: 345). Mindfulness meditation seems close at hand for a religious naturalist, due to the ways in which it can ‘help to facilitate ethical self-realization’ (Steinhart 2018: 346; see Macalister 2021: 1032–1033). Following Macalister, we can see how a number of naturalists have proposed different practices to orient the mind towards more spiritual perspectives (2021: 1028–1032), including mindfulness meditation, spending time in nature, gardening, and developing attitudes of appreciation and recognition that life is precious. Another form of activity involves ‘putting values into practice’ which, in light of the religious naturalist emphasis on ecological sustainability, might entail personal actions to support more sustainable relationships with the environment, such as ‘recycling, reusing, reducing’, or participating in awareness-raising eco-focused events.

In Naturalizing God? (2021: 32, 34–35), Mikael Leidenhag discusses, in a similar way to Steinhart and Macalister, how ecological mindfulness plays a significant part in the epistemology of religious naturalism; an orientation especially evident in Ursula Goodenough’s emphasis on the necessity of a mindful appreciation of the findings of biology, psychology, and anthropology. Goodenough urges religious naturalists to be mindful of how life has evolved, the fragility of life and its ecosystems, that all of life is interconnected, of human creativity, and our natural need for personal wholeness and social coherence (2001: 588). Mindfulness is no longer just about ‘breathing and walking [but] we are now able to contemplate […] the molecular and genetic underpinnings of the body and its evolution from simpler forms’ (2001: 588). Lastly, some have explored whether transformational festivals (such as rave), ayahuasca ceremonies, and psilocybin ceremonies may afford further avenues for religious expression (Steinhart 2018: 346–349).

3.1 Is Christian naturalism religiously relevant?

Christian naturalism seeks to place traditional theological doctrines on a naturalistic footing, showing how soteriology, Christology, human nature, morality, etc. can be rendered compatible with an ontology that affirms the primacy of the natural order – construed in a physicalist or emergentist manner. Given the revisionist implications of this worldview, one may wonder if the end-product, as it were, is religiously relevant. The process theist David Ray Griffin (discussed in section 1.3) has argued in relation to Willem Drees’ religious naturalism ‘that the religious beliefs are so minimal as to be virtually nonexistent’ (Griffin 1997: 595). We could relate this critique to Charley Hardwick’s physicalism, according to which belief in God is interpreted in a non-realist manner; as a way of viewing the world or a ‘theistic seeing-as’. The religious naturalist could respond in several ways. They might say, ‘who gets to determine what’s religiously relevant?’, suggesting that the critique may, in fact, be question-begging by assuming a metaphysically realist conception of religious relevance, whereby a religious proposition has to refer to an objective, independent reality. They might also, in the spirit of Jerome Stone, concede that religious naturalism is unable to offer the whole package but that it, nevertheless, ‘suffices magnificently’ (2017: 4).

It is worth quoting Stone in full:

Is nature enough? Hardly! Nature is not self-explanatory. Nature is not completely meaningful. Nature does not provide for complete and final fulfillment of our deepest desires and longings. Nature does not provide answers to our moral queries. Nature does not provide a foundation for our epistemological, metaphysical, and axiological searches. In short, nature is not enough. But it’s all we have, and it will have to do. (Stone 2003: 783)

3.2 Can religious/Christian naturalism be demarcated?

In ‘Religious Naturalism and its Rivals’ (2013), Mikael Stenmark discusses both ‘God-talking’ (Kaufman) and ‘no-God-talking' (Crosby) religious naturalists and the challenges that these two camps face. First, Richard Dawkins, ‘a well-known advocate of non-religious naturalism or atheism’ has (2013: 542), in a similar way to some religious naturalists, expressed reverence and awe in light of scientific depictions of the natural order. Should Dawkins, then, be included within the wider camp of religious naturalism when his more aggressive anti-religious stance and secular outlook may be seen as incompatible with the broader sentiment of religious naturalism? As Stenmark observes, ‘religious naturalists have work to do here to distinguish their view from non-religious naturalism’ (2013: 543). A religious naturalist may, moreover, express a reluctance in doing so as a neat definition of this religious outlook may imply that it becomes an ism – an unattractive implication for many religious naturalists (see section 2.4).

A challenge facing the God-talking naturalist, such as Gordon Kaufman, is that it is not obvious why naturalism should be preferred over, say, Paul Draper’s religious agnosticism (2002); someone who hopes and lives his life as if there is a God but does not feel confident enough to exclude the possibility that naturalism/atheism is true. The apophatic work of Kaufman expresses something quite similar (1993). Many religious naturalists would simply retort by saying that, while agnosticism cannot be excluded, they feel sufficiently confident in the truth of naturalism. As Stone says, while naturalism has not been proven, ‘it does make more sense to many of us than alternate views’ (2008: 14).

3.3 The problem of evil and suffering

It is correct as Michael Raposa notes that many thinkers have moved to religious naturalism from classical theism due to the problem of evil (Raposa 2018). Donald Crosby has in several writings argued how religious naturalism, or a religion of nature, can respond to the problem of evil and suffering, most clearly articulated in Living With Ambiguity: Religious Naturalism and the Menace of Evil (2008). Crosby is aware that there is a problem of evil for religious naturalism but maintains that it has the resources to respond to it and is better equipped to do so compared to the traditions of Western classical theism. However, Leidenhag has responded to Crosby’s arguments, suggesting that Crosby is forced to give up the contention that all of nature is worthy of reverence and adopt a qualified religion of nature whereby our reverence should only focus on the life-promoting and sustaining forces of nature (2021: 133–134). Perhaps, then, those forms of religious naturalism that consider particular aspects of nature to be worthy of reverence, rather than nature in its totality, are better able to mount a defence in light of evil and suffering. Or, perhaps a religious naturalist, in a similar way to a theistic invocation of the divine hiddenness argument, can retort by saying that humans are not cognitively equipped to answer this pressing issue due to the complexity and mysteriousness of nature (as expressed by Karl Peters and Gordon Kaufman in particular).

3.4 The philosophical challenges to naturalism

As described previously in this article, religious naturalists have articulated their religious views through two distinctive ontologies: physicalism and emergence theory. It should be noted that both ways of understanding nature raise critical issues and have been critiqued from multiple perspectives.

Willem Drees, for example, has been critiqued by David Ray Griffin for too quickly assuming the truth of ‘materialistic naturalism’ and that this position is unable to account for freedom and subjectivity (1997). Griffin argues that:

Drees’s concept of scientific explanation as reductionist explanation entails that our “manifest image” of ourselves as persons having an inner life, with its emotions and apparent freedom, must be ontologically reducible, meaning explainable in principle […] in terms of the entities and forces of physics. (Griffin 1997: 609)

The problem, however, is that even Drees’ position presupposes the reality of freedom, speaking of ‘moral effort’, ‘self-determination’, and ‘rational reflection’ (Griffin 1997: 610–611). Those religious naturalists that espouse a more restrictive ontology need to show how the manifest image can be retained, so as to avoid what looks like a contradiction. Leidenhag remarks on a similar tension in Hardwick’s Christian physicalism (see Leidenhag 2021: 109–133).

Emergent naturalism, despite being ontologically less restrictive, faces its own share of potential problems. As we have seen, emergence theory features in the proposals of Stuart Kauffman (2008), Ursula Goodenough (1998; 2023), Gordon Kaufman (2004; 2010), and Karl Peters (2002). Scot Yoder (2015) and Mikael Leidenhag (2013) have both suggested that emergence theory, despite its non-reductive ambitions, seemingly fails in upholding the causal effectiveness of higher-level properties, thus it may not hold the key to ‘reconcile the manifest and scientific images in such a way as to make talk of agency, value, and meaning consistent with naturalism’ (Yoder 2015: 162). Both Leidenhag and Yoder draw on the influential work of Jaegwon Kim (1993; 1995; 1999; 2006) in demonstrating the tension between emergent properties and the monist requirements of a naturalistic worldview. Indeed, Leidenhag argues that for ‘downward causation to make sense, the causal powers of emergent properties […] must be located in something nonphysical’, which renders strong emergence (recall section 2.1) incompatible with naturalism (Leidenhag 2021: 72). Yoder echoes this reasoning as well, ‘Though emergentism is intended to be fully naturalistic, it is ultimately unable to close the door to supernaturalism’ (Yoder 2015: 167). In this way, a religious naturalism based on emergence theory may face significant challenges when it comes to reconciling the core ingredients of a religious worldview with the fundamental principles of metaphysical naturalism.