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Science and Religion, Ian Barbour's Legacy


I. Introduction – II. Status Quæstionis in Science and Religion before Barbour – III. Four-fold Typology – VI. The Essential Role of Philosophy – V. Evaluation – VI. Influence on other Scholars. 1. Arthur Peacocke. 2. John Polkinghorne. 3. Robert John Russell. – VII. Conclusion and Perspectives.  

I. Introduction

One of the most influential figures in the field of science and religion in the twentieth century was undoubtedly Ian Graeme Barbour (1923-2013). Trained both as an experimental physicist (PhD University of Chicago), and a Christian theologian (BDiv Yale Divinity School), Barbour was well positioned to explore the potential interaction of the two fields. Over the course of his academic career, he made contributions to natural science, theology, and the methodology of the burgeoning interdisciplinary field in the Anglophonic world (Russell, 2004). While some of his Protestant confrères had embraced the “conflict hypothesis” between religion and science, Barbour’s upbringing and intellectual formation led him to explore other possibilities. Early in his career he proposed three other modalities of interaction: 1) that the two fields could be viewed as independent of one another, 2) that a dialogue was possible acknowledging conceptual and methodological parallels, and 3) that integration was achievable with a common philosophical foundation. 

Barbour also appreciated the essential role of epistemology and metaphysics in this interdisciplinary space. Through his application of Whiteheadian process thought and critical realism, he built a bridge between religion and science that would inspire other scholars to take up the important task of relating the two fields. Barbour demonstrated the relevance of ontology, identity and change, causality, as well as necessity and contingency in theology and science. He also affirmed the human person’s ability to come to know objective truth. This entry explores Barbour’s marvelous legacy in science and religion, even while raising a few critical questions about his methodology.

II. Status Quæstionis in Science and Religion before Barbour

Ian Graeme Barbour came of age at a liminal moment in the Anglophonic, Protestant world. The “conflict hypothesis” between science and Christianity had already gained wide acceptance among some Protestants. In the UK, a major instigator of the so-called “war between religion and science” was Thomas Henry Huxley (1825-1895), an influential figure in the nascent anti-theism movement (Gilley and Loades, 1981). Huxley was vehemently opposed to “organized religion” in general, and the Catholic Church in particular. For example, Huxley asserted that the Catholic Church “carefully calculated for the destruction of all that is highest in the moral nature, in the intellectual freedom, and in the political freedom of mankind” (Bibby, 1959, p.155). In the USA, John William Draper’s 1874 book, History of the Conflict between Religion and Science and Andrew Dickson White’s 1896 book, A History of the Warfare of Science with Theology in Christendom gained popularity. White’s book was eventually translated into German, French, Italian, Swedish, and Japanese.

The American religious context of the first half of the twentieth century was undoubtedly formative for Barbour, so it is necessary to mention some of the major events and movements. In the early 1900s theological modernism began to greatly influence the Protestant mainline churches (Fosdick, 1922). Against this rising tide, the Christian fundamentalist movement responded with great fervor. Lyman and Milton Stewart of Union Oil commissioned a set of ninety essays which would become The Fundamentals: A Testimony to the Truth in 1915. The Presbyterian pastor James Orr wrote the article “Science and the Christian Faith,” promoting progressive creationism, i.e., a form of “Old Earth” creationism which accepts the mainstream geological and cosmological estimates for the age of the Earth and the universe as well as some tenets of biology such as microevolution (Torrey and Dixon, 2003). In 1925, the infamous Scopes Monkey Trial occurred in the State of Tennessee (Moran, 2002). Meanwhile, at Yale Divinity School, Union Theological Seminary, and elsewhere, Neo-Orthodoxy began to take a definitive form in the US in 1930s, especially with the writings of Reinhold Niebuhr. While rejecting many of the developments in nineteenth century liberal theology, Neo-Orthodoxy is distinct from fundamentalism in many ways, including the general acceptance of Biblical criticism. The 1950s saw a boom in the (sometimes non/inter-denominational) Evangelical movement with figures such as Billy Graham, Bob Jones Sr., and John R. Rice.

Born in 1923 in Peking, China, to a Scottish Presbyterian father and an American Episcopalian mother who were both lay missionaries, Ian Barbour was raised in a devout Christian home. George Brown Barbour, Ian’s father, was a professor of geology and his mother, Dorothy, taught in the Department of Religious Education at Yenching University (West, 1976, pp. 34-39). After the family moved to the United States, Ian would go on to earn a BS in Physics from Swarthmore, an MS from Duke, and in 1950 a PhD from the University of Chicago (Barbour, 2017, p. 6). Barbour received a faculty appointment to Kalamazoo College and in 1953 obtained a Ford Foundation Fellowship to support his sabbatical at Yale Divinity School. This experience studying theology and ultimately earning a BDiv degree in 1956 would be transformational for Barbour. After his sabbatical experience, he went on to take a teaching position at Carleton College, which would become his academic home (Laracy, 2021, p. 25). Barbour then set out on a life-long quest to explore other typologies of interaction between science and religion, beyond the conflict approach. This constitutes a substantial aspect of his legacy in the field.

III. Four-fold Typology

Among his many accolades, Barbour was invited to deliver the esteemed Gifford Lectures in Scotland (1989-1991). The first series of lectures, which would eventually be published as Religion in an Age of Science, introduced Barbour’s now famous four-fold typology of interaction: conflict, independence, dialogue, and integration. The conflict hypothesis that he attempted to confront was held by both atheists and some of his fellow Christians. Barbour observed that whether recalling regrettable incidents in Church history, or commenting on current events, the attention of the popular media was often directed to advancing the conflict hypothesis (Barbour, 2000, p. 2).

The promoters of the conflict hypothesis assert that religion in general, and Christianity in particular, make truth claims that are irreconcilable with modern, empirical science. The only logically consistent option for an individual is either to choose Christian faith and suspend reason or choose reason and science, thereby rejecting God and the Church. Barbour, on the other hand, argues persuasively that science and religion can also be considered independent of each other, in dialogue with each other, or even integrated.

The independence hypothesis allows religion and science to coexist in peace. The two fields remain in distinct domains. Theological language is clearly different from scientific language and serves a unique function. Science and religion can be seen to offer complementary views of reality that do not conflict, perhaps analogous to the wave-particle duality in quantum mechanics. However, Barbour observes that “compartmentalization avoids conflict, but at the price of preventing any constructive interaction” (Barbour, 2000, p. 2). Barbour views this “complementary view” approach as generally useful, and certainly superior to conflict, as it “underscores the abstractive and symbolic character of concepts, the indirectness of their relation to observable phenomenon, the limitations of models, and the inadequacy of attempts to visualize reality in terms of the categories of everyday experience” (Barbour, 1966a, p. 294).

However, Barbour does not remain satisfied with the independence view. His intuition and experience led him to explore richer forms of interaction between science and religion. The approach of dialogue is established upon the fact that there are similarities in principles and methods between theology and science. For example, both disciplines make extensive use of conceptual models and analogy. A dialogue can also begin when science reaches “limit questions.” According to Barbour, these are “ontological questions raised by the scientific enterprise as a whole but not answered by the methods of science” (Barbour, 1997, p. 90). For example, Why is there a universe? or Why is it intelligible? For many, these are religious questions that are best answered by the discipline of theology. Dialogue can also be promoted when scientific concepts stimulate theological reflection. For example, if one adopts a “Copenhagen-type interpretation” of quantum mechanics (Wimmel, 1992) which asserts that physical processes at the quantum scale are intrinsically indeterministic, one may ask if God is the “Great Determiner” (Barbour, 2000, p. 3)? 

Ultimately, Barbour’s quest is to rigorously integrate science and religion. His integration approach is initially inspired in part by the Catholic Church’s tradition of natural theology, especially Thomas Aquinas’ Five Ways. These arguments support the rationality of belief in God based on motion, causation, contingency, degree, and finality. Barbour notes how the discoveries of modern science can lend a new degree of sophistication to natural theology. He points out how fine-tuned phenomena such as an expansion rate of the universe that allows galaxies to form, the relative strength of the strong nuclear force that enables the formation of elements larger than hydrogen, as well as the asymmetry of the particle/antiparticle ratio that allows for ordinary matter, can all contribute to a modern natural theology rooted in cosmology (Barbour, 2000, pp. 57-58).

However, in the final analysis, likely as a result of the Barthian influence at Yale Divinity School, Barbour does not endorse a program of renewing natural theology. In 1966, Barbour wrote, “There is little interest today in looking to nature for support for religious beliefs; the once-popular arguments of ‘natural theology’—such as the claim that evidences of design prove the existence of a Designer—appear dubious logically and, more significantly, reflect a speculative approach very different from the attitudes characteristic of religion itself” (Barbour 1966a, p. 2). Almost forty years later, he wrote, “Even if the argument [for the existence of God from natural theology] is accepted, it leads only to the distant God of deism…not the God of theism actively involved with the world and human life” (Barbour, 2002, p. 3). 

No doubt influenced by the life and work of Teilhard de Chardin, SJ, a close friend of his father, Barbour prefers to promote the integration of science and religion through “theologies of nature.” In this approach, one begins in one’s own theological tradition. Doctrines are then reformulated in light of the discoveries of contemporary natural science to bring religious belief into greater harmony with mature science. As examples, Barbour suggests revisiting Christian doctrines on creation, providence, and human nature (Barbour, 1997, pp. 100-102). 

The highest degree of integration is only possible, according to Barbour, when a common epistemology and metaphysics are utilized to support both theology and science. Always a realist in his work as an experimental physicist, Barbour develops a philosophy of knowledge called “critical realism” to support the two fields (Barbour, 1966b, p. 29). He also adopts, and in many ways simplifies, the elaborate philosophy of being of Alfred North Whitehead known as “process thought.” Barbour views process philosophy (and theology) as “applicable to experience” and “coherent” for religion and science (Barbour, 1966a, pp. 129-130). Barbour’s epistemology and metaphysics will be discussed in greater detail in the next section.

Barbour’s work formulating an interaction typology for science and religion has stimulated other scholars to engage in a similar quest. Some of these systems are revisions of Barbour’s, while others are completely novel. Examples include the typologies of John Haught, Ted Peters, Willem B. Drees, Mikael Stenmark, Christopher Southgate, and Graham Buxton (Laracy, 2021, pp. 36-37). In any case, the impact of Barbour’s typology is very extensive.

IV. The Essential Role of Philosophy

As alluded to in the previous section, a substantial aspect of Ian Barbour’s legacy is his appreciation of the role of philosophy to serve as a “bridge” that connects the academic disciplines of science and theology. Like Thomas Aquinas in the thirteenth century, and Thomists of the twenty-first century, Barbour realizes the importance of epistemology and metaphysics in both the theological and scientific enterprises. In this section, we explore Barbour’s legacy with respect to critical realism and process thought.

Kees van Kooten Niekerk describes critical realism (Kritischer Realismus) as “those positions which take account of Kant’s critical epistemology but deny that the subjectivity of our experience makes it impossible to acquire valid knowledge of the external world as it is in itself” (van Kooten Niekerk, 1998, p. 51). The eighteenth century Prussian philosopher, Immanuel Kant, is famous for his assertion that man cannot know things in themselves, i.e., the noumenon, but only the impressions that they make in one’s mind, i.e., the phenomenon (Kant, 2007 part I, bk. II, chap. 3). He further argued for an “empirical realism” alongside a “transcendental idealism”; Kant claimed that his transcendental idealism could support a form of realism at the empirical level (Eisler, 1929, p. 623). 

Andreas Losch and Joseph R. Laracy have surveyed the variety of contemporary forms of critical realism (Losch, 2009; Laracy, 2021, pp. 75-85). Scholars such as Roy Wood Sellars, Jacques Maritain, Bernard Lonergan, SJ, Roy Bhaskar, Ernan McMullin, N.T. Wright, Jacobus Wentzel van Huyssteen, Alister McGrath, and others all employ the term “critical realism” but often with very different meanings. Barbour’s critical realism comes from his background as a physicist and the actual practice of experimental science.

Barbour first introduced his notion of critical realism in 1966 with the inaugural issue of Zygon: Journal of Religion and Science (Barbour, 1966b, p. 29) and greatly popularized it with his now-classic text, Issues in Science and Religion (Barbour, 1966a, pp. 164-165). He specifies this epistemology by contrasting it with other popular philosophies of knowledge from the mid-twentieth century: what he calls “naïve” realism, positivism, instrumentalism, and (full blown) idealism. True naïve realism posits that human perceptions are direct registers of reality. It ignores the immateriality of form, the relationship of the concept to the thing, and the abstraction of essences from substances. Barbour regards the positivistic view of scientific theories as simply summaries of data, or “mental devices for classifying observations,” (Barbour, 1966a, p. 162) as grossly inadequate. He also strongly criticizes the instrumentalists who deny the real correspondence of theories to physical objects in the world. What use is an epistemology that cannot adjudicate between two contradictory theories that both claim to explain the same data? As an experimental physicist with a realist perspective, Barbour believes that the Neo-Kantian idealist position is utterly absurd. He points out the senselessness of Henry Margenau’s assertion that “reality does change as discovery proceeds” (Margenau, 1950, p. 295) when he refers to Margenau’s claim that the neutron did not exist until it was “invented” in 1932 (Barbour, 1966a, p. 168).

It is important to note that some twentieth century Thomists, e.g., Étienne Gilson, were wrongly accused of naïve realism for not accepting the epistemological starting point of Cartesian doubt or the Kantian critique of knowledge. On this issue, Frederick D. Wilhelmsen astutely points out that "when man apprehends being he is no longer in the order of essence, quod quid erat esse, but of the act of existence. Thus, Thomism transcends the critical problem. Once it is understood that the knowing subject is in direct, living communion with beings that are in act, the supposed problem of bridging the gap between an abstract mind and an equally abstract being is seen in all its poverty, resting in the last analysis on an essentialist notion of being" (Gilson, 2012, p. 19).

Furthermore, the distinguished professor of physics, Stanley L. Jaki, OSB, writes, "that even the fact, let alone the nature, of external reality, however ordinary, cannot be proven by mere logic or mathematical formulas does not make one’s immediate registering of external reality a less than fully rational process. To know the existence of things is in fact the very first step in reasoning. Any critical knowledge or philosophy which does not accept this will remain a mere criticism of criticism and not a criticism of the external reality one registers, and not even one’s own registering it" (Jaki, 1993, pp. 108-109).

Nonetheless, Barbour attempts to construct a via media between classical, metaphysical realism, exemplified by St. Thomas and the idealism of Kant. 

Following Whitehead, Barbour places significant emphasis on human subjectivity in the process of knowing. He posits that

    1. reality consists not of things but of events occurring in networks of relations which included both the knower and the   known; 
    2. knowledge arises not from either subject or object alone but from a situation of mutual interaction;
    3. scientific language is symbolic, deriving from the subject’s selective abstraction from the total situation (Barbour, 1966a, p. 171).

Barbour’s introduction to Whitehead’s process thought came through Daniel Day Williams and Gordon D. Kaufman in the early 1960s. These experiences led him to read extensively the works of process philosophers and theologians such as Charles Hartshorne, John B. Cobb, and David Ray Griffin. Whitehead’s metaphysics postulates that “nature is a structure of evolving processes” (Whitehead, 1931, p. 106). In an effort to overcome the Cartesian duality of physical and spiritual substances, Whitehead eliminates the category of substance from his ontology. He theorizes a “philosophy of organism” based on four fundamental concepts: actual entities/occasions, prehension, nexus, and the ontological principle. Actual entities/occasions include subatomic particles, plants, animals, humans, and God. They may interact with each other through their mutual prehensions, i.e., feelings of things, thus giving rise to nexūs (plural of nexus), i.e., particular acts of togetherness. Whitehead writes that “the ontological principle can be summarized as: no actual entity, then no reason” (Whitehead, 1969, p. 23).

Ian Barbour simplifies and applies Whitehead’s novel, complex metaphysics for his work in the science and religion field. He sees Whitehead’s system as consistent with the modern scientific worldview which takes a multi-level view of nature and places great emphasis on dynamicity, e.g., evolutionary processes. Four aspects of Whitehead’s philosophy are particularly appealing to Barbour: the primacy of time, the interconnection of events, reality as an organic process, and the “self-creation” of every entity.

“Becoming” is more important than “being” in the process perspective. Barbour shares Whitehead’s view that “transition and activity are more fundamental than permanence and substance” (Barbour, 1997, p. 285), hence the primacy of time. Barbour also appreciates the emphasis in Whitehead’s thought on entities being defined by their interactions, hence the prominence of the interconnection of events. The notion of reality as an organic process thus flows from the previous two principles. The principle of the self-creation of every entity is rooted in Whitehead’s belief that allentities, regardless of their complexity, are experiencing subjects (Whitehead, 1969, p. 23). Furthermore, events are not only instances of potential interactions, but entities in their own right and thus enjoy “individuality.”

Barbour’s process perspective is a dynamic network of particular “moments of experience,” corresponding to Whitehead’s “actual entities” or “actual occasions.” Barbour changes the language slightly by referring to them at times as “entities” (to highlight their integration) and at other times as “events” (to highlight their temporality). Whiteheadian causality is nicely simplified by Barbour in three steps: 

    1. Every new entity is in part the product of efficient causation, which refers to the influence of previous entities on it. Objective “data” from the past are given to each present entity, to which it must conform, but it can do so in alternative ways. 
    2. There is thus an element of self-causation or self-creation, for an entity unifies its “data” in its own manner from its unique perspective on the universe.    Every entity contributes something of its own in the way it appropriates its past, relates itself to various possibilities, and produces a novel synthesis that is not strictly deducible from its antecedents. 
    3. Thus a creative selection occurs from among alternative possibilities in terms of goals and aims, which is final causation (Barbour, 1997, p. 286).

In summary, Barbour suggests that each novel occurrence in the universe is to be understood as a “present response (self-cause) to past entities (efficient cause) in terms of potentialities grasped (final cause)” (Barbour, 1997, p. 286).

V. Evaluation

Regrettably, Barbour’s critical realism does not give an adequate account of the significant metaphysical fact that the simple actuality of being precedes the knowing of any particular human subject. He also excludes the possibility of certain knowledge in theology (Laracy, 2021, pp. 175-183). Barbour’s philosophy does not account for esse simplex—the simple “to be,” the act of existing. In addition, his process metaphysics does not acknowledge God as completely perfect actuality. There is also a detrimental elevation of activity over substance. Esse simplex, properly understood, involves total stability in God. In God’s creation, it is the foundational stability of a nature/essence with the possibility of the actuality of potencies. 

There are in fact numerous theological consequences to Barbour’s process thought which put him at odds with the broader Christian tradition. His early writings flatly reject the Christian doctrine of creatioex nihilo, stating that “it is not a Biblical concept,” (Barbour, 1966a, p. 384) despite the fact that it is supported by Genesis 1:1, Isaiah 45:18, Psalm 33:6-9, Judith 13:18b, Sirach 43:33, 2 Maccabees 7:28, Romans 4:17, Colossians 1:16, Hebrews 1:1-2, Hebrews 11:3, and Revelation 4:11. In his later writings, Barbour seems to try to retain a notion of ex nihilo, but reinterprets its meaning (Barbour, 1990, chap. 5). 

In addition, his theological anthropology which denies that the immaterial soul is the substantial form of the human person, his implicit panentheism, his denial of the perfection of God (e.g., God’s omnipotence and omniscience), and the numerous consequences of neglecting substances and essences place him seriously in conflict with most forms of Christian doctrine. Whitehead and Barbour depart radically from Nicene-Constantinopolitan Symbol of Faith when they allow their metaphysics to “overwhelm” Divine revelation (Laracy, 2021, p. 183). One evident problem with his approach to developing a theology of nature, i.e., revising religious doctrines based on scientific developments, is that public, Divine revelation (which ended with the death of John the Evangelist) is made subservient to a discipline which is never definitively settled and always reforming its theories-natural science. 

All things considered, Barbour’s insistence on realism in science and theology, tied to his integration modality of a systematic synthesis of the two disciplines, is a substantial contribution to the field. In a time when many philosophers of science were promoting instrumentalism, positivism, and idealism, Barbour always affirmed the ability of the human mind to come to know truth, albeit partially and imperfectly. Despite these fundamental theological issues in his process thought, Barbour’s engagement with metaphysics shows the relevance of ontology, identity and change, causality, as well as necessity and contingency. Postmodern thinkers critically engaged him for his foundationalism (McFague, 1996, p. 25), but he never wavered. Barbour’s appreciation for, and engagement with, a realist metaphysics for theology and science provides vital support for religious doctrines “to be universal, perduring, self-same, and normative” (to borrow a phrase from Guarino, 2005, p. 25). 

VI. Influence on other Scholars

Finally, a substantial aspect of Ian Barbour’s legacy in religion and science is his direct impact on other scholars in the field. In his endorsement of Barbour’s book, When Science Meets Religion: Enemies, Strangers, or Partners, theoretical physicist and Anglican theologian, John Polkinghorne, describes Ian Barbour as the “doyen of contemporary writers on science and theology” (Barbour, 2000, i). The Lutheran theologian, Hans Schwarz, refers to Barbour as the “Grand Senior of the Dialogue” between science and religion (Schwarz, 2014, p. 108). While an entire book could be written on Ian Barbour’s influence on other scholars, we shall look very briefly at three major researchers in the religion and science field on whom Barbour had a substantial effect: Arthur Peacocke, the aforementioned John Polkinghorne, and Robert John Russell.

1. Arthur Peacocke. Arthur Peacocke earned a DPhil from Oxford in 1948 under the Nobel Prize winning chemist, Sir Cyril Hinshelwood. In 1971, he earned the BDiv degree from the University of Birmingham and was ordained a presbyter in the Church of England. He then went to Clare College, Cambridge, as fellow and dean, teaching both theology and biochemistry. Oxford brought Peacocke back in 1984 to serve as director of the newly founded Ian Ramsey Centre for Science and Religion. He would ultimately be awarded the ScD and DD degrees from Oxford, named an honorary canon of Christ Church Cathedral, deliver the Gifford Lectures 1992-93, and win the Templeton Prize in 2001 (Polkinghorne, 2006).

In his 1971 book, Science and the Christian Experiment, Peacocke acknowledges Barbour’s legacy in the field. Peacocke writes, "An attempt of this kind cannot hope to deal at all fairly and comprehensively with the many issues on which there should be at least a dialogue between those involved in the scientific and theological enterprises. These have been magisterially surveyed by I.G. Barbour in his Issues in Science and Religionand I willingly refer the reader to that systematic and documented account (Peacocke, 1971, vi)". Later, in Creation and the World of Science, as well as Intimations of Reality: Critical Realism in Science and Religion, Peacocke advocates for Barbour’s epistemology. He also supports a number of ideas from Barbour’s book Myths, Models, and Paradigms. In 2000, Peacocke stated that “no surer and fairer guide to the proliferating literature on the relation of science and religion can be found than Ian Barbour” (Barbour 2000, i). Barbour and Peacocke are very much in agreement with their views on evolution, emergence, top-down causality, and creatio continua. Peacocke also follows Barbour with his preference for theologies of nature, dipolar concepts of God, and an open-ended universe, i.e., unknowable even to God (Barbour, 2008, p. 91). One way that Peacocke however differs from Barbour and other process theologians is in his “emergent monism.” Peacocke rejects panpsychism and therefore does not suppose that low-level entities have any interiority or subjectivity (Peacocke and Clayton, 2007, pp. 12-16).

2. John Polkinghorne. John Polkinghorne was also greatly influenced by Barbour. Polkinghorne earned a PhD in theoretical physics from Cambridge in 1955. He studied under the Nobel Prize winners, Paul Adrien Maurice Dirac and Abdus Salam. Polkinghorne eventually returned to teach mathematical physics at Cambridge and earned the ScD degree. In 1979, he resigned from the faculty to enter the Anglican seminary at Westcott House. He was ordained in 1982 and four years later was named President of Queens’ College, Cambridge. Like Barbour and Peacocke, Polkinghorne delivered the Gifford Lectures (1993-94) and won the Templeton Prize in 2002.

Polkinghorne acknowledges the extensive legacy of Ian Barbour in the religion and science field. He writes, “There is no doubt that [the publication of Barbour’s 1966 book, Issues in Science and Religion,] was indeed a seminal event in terms of its wide influence in the academic world” (Polkinghorne, 2004, p. 4). Similar to Peacocke, Polkinghorne also endorses Barbour’s critical realism (Polkinghorne 2008, p. 150). Polkinghorne emphasizes the “realism” in critical realism through his notion of verisimilitude in theological and scientific inquiry (Polkinghorne, 1998, p. 104). As Paul Allen points out, Polkinghorne’s critical realism aligns closely with Barbour’s correspondence theory of truth, “an epistemological verisimilitude in arriving at a fact for ontological categorization” (Allen, 2006, p. 34). Polkinghorne’s epistemology was also influenced by Bernard Lonergan (Polkinghorne, 1991, pp. 5-17). Metaphysically, Polkinghorne follows Barbour in proposing dipolar monism. However, he also critically engages Whiteheadian thought. Polkinghorne argues that process philosophy is irreconcilable with the theoretical foundations of quantum mechanics. He further engages Whitehead and Barbour for deviating from the foundations of Christian doctrine, especially in the Biblical teachings of Christology and Trinity (Polkinghorne, 2004, pp. 18-19). 

3. Robert John Russell. Barbour’s influence on Robert John Russell is another substantial aspect of his legacy. As an undergraduate at Stanford University, Russell was impacted by Barbour’s ideas after reading Issues in Science and Religion. He went on to earn a MS in physics at UCLA, a BDiv and MA in theology at the Pacific School of Religion at Berkeley, and a PhD in physics in 1978 at UC Santa Cruz. He was also ordained a minister in the United Church of Christ that year. Russell’s first faculty position in physics was at Carleton College, Barbour’s intellectual home. He later returned to California and founded the Center for Theology and the Natural Sciences. Russell eventually joined the faculty of the Graduate Theological Union as the Ian G. Barbour Professor of Theology and Science (Russell, 2009).

Russell regards Barbour’s 1966 book as a “turning point in the constructive relations between science and religion” (Russell, 2017a, p.1). He enthusiastically embraces Barbour’s critical realism as the most fitting epistemological bridge between religion and science (Russell, 2003, pp. 1-3). Russell points out that even after fifty years Barbour’s epistemology continues to be “defended, deployed, and diversified widely in theology and science, and continues to be presupposed by most working scientists, by many theologians, and in much of the public discourse about both science and religion” (Russell, 2017b, p. 36). Russell also supports Barbour’s integration paradigm of developing theologies of nature. He uses the metaphor of a “bridge” to moves philosophical themes such as contingency and finitude, as found in Big Bang Cosmology and the Christian doctrine of creation ex nihilo, from one community to the other. Similar to Barbour, Russell believes that there can be “traffic” in both directions, i.e., from theology to science and science to theology. He refers to his approach as the method of “Creative Mutual Interaction” (CMI) (Russell, 2008; 2012). In light of his substantial contribution to the science and religion field, Barbour and others contributed to a festschrift in honor of Russell entitled God’s Action in Nature’s World: Essays in Honour of Robert John Russell. (Hallanger and Peters, 2006). 

Russell differs with Barbour when it comes to process theology. Barbour adopts Whitehead’s approach of “organicism,” described as panexperientialism by David Griffin (Griffin, 1977). According to Barbour, this philosophy of mind and being “attributes experience in progressively more attenuated forms to persons, animals, lower organisms, and cells (and even, in principle, to atoms, though at that level it is effectively negligible), but not to stones or plants or other unintegrated entities” (Barbour, 2002, p. 95). In contrast, Russell is not a process theologian and tends to work with non-foundationalist epistemologies. Russell does express a metaphysical preference for a theory of ontological emergence in which “the new properties and processes that emerge at higher levels of organization indicate the ontology of the world, though monistic, cannot be reduced to that described by physics alone.” (Russell and Wegter-McNelly, 2007, p. 517). Russell’s approach moves in the direction of Paul Tillich’s multidimensional unity of life perspective (Tillich, 1963, p. 3: III/IV/I/A).

VII. Conclusion and Perspectives 

The science and religion field certainly has a strategic relevance in contemporary culture. A 2015 Pew Research Center study showed that 59% of Americans surveyed believed that science and religion are often at odds. The research indicated that respondents who were not affiliated with any religious tradition were especially likely (76%) to think that science and religion conflict (Funk and Alper, 2015). A 2016 Pew survey showed that among those who indicated that they abandoned religion all together, many mentioned “science” as their reason. One person’s reason for non-belief was: “I’m a scientist now, and I don’t believe in miracles.” Pew also found that “common sense,” “logic,” and “lack of evidence” were common reasons for abandoning religious faith (Lipka, 2016). Barbour’s legacy of showing the compatibility of reason and revelation, science and theology, experiential knowledge and faith, has a felicitous relevance, perhaps now more than ever.

Many of the issues in science and religion that Barbour engaged during his prolific scholarly career which began in the 1940s remain apposite today. Barbour understood well that while science is a tool for understanding the world, religion is an invaluable companion for our own self-understanding in the world. He recognized the fact that science is always enculturated and can be utilized as a tool for power. The rise and appreciation of the social studies of science and technology was, in many ways, anticipated by Barbour. He was also truly ahead of his time in realizing that interdisciplinary scholarship is rarely binary, i.e., involving only two fields. In his lifelong work to place natural science and theology in a mutually beneficial relationship, Barbour employed disciplines such as history, epistemology, and metaphysics. While issues of concern to Barbour like the limits of science and the importance of ethics in scientific, engineering, and medical research remain extremely relevant (Barbour, 1992), new issues have also emerged. 

Early on, much of the research in science and religion engaged physics as the scientific reference field. This is understandable considering that the physical sciences were the first ones to achieve maturity in the modern period, and that physics clearly is the most fundamental natural scientific field, embracing the full breadth of the material world. However, recent developments in biology, medicine, psychology, and anthropology are impressive, and merit similar attention. Here, the issues at stake are not limited to evolutionary biology, but also include viewing organisms as teleological systems, ecology as a science of relations between organisms and their environment, and the mind-brain relationship in light of developments in neuroscience. Scholars in science and religion today are also exploring questions around sex / gender and theological anthropology (Finley, 2015), climate science and the care of the planet (Haffner, 2008), as well as ethics in computing related to artificial intelligence and privacy (Anderson, Laracy and Marlowe, 2020). 

While Barbour ultimately favored process thought, this is by no means the only viable ontological framework. Recent developments in Neo-Thomist philosophy of nature and metaphysics (e.g., Dodds, 2012; Feser, 2019; Tabaczek, 2021) offer a very promising approach to engaging the current scientific panorama. Of course, contemporary science and the philosophy of science face challenges unknown in the Middle Ages. Hence, contemporary Neo-Thomists wrestle with open questions around emergence, complexity, non-locality, top-down causality, holism, and systems theory. 

The science and religion field would likely benefit from a ressourcement based on the insightful philosophical and theological reflection on creation by earlier Christian thinkers such as St. Basil of Cæsarea, St. Augustine of Hippo, St. Gregory of Nyssa, St. Maximus the Confessor, St. Bonaventure, Hugh of St. Victor, Bl. Duns Scotus, Nicholas of Cusa, and others. This expansion of sources and styles would complement Barbour’s understanding of the possible relations between science and religion (see Sec. III). Barbour’s work represents a crucial reference point, but does not exhaust the possible relationships between religion and science.    

Contributing to the field of science and religion requires in-depth, specialization in a discipline complemented by a broader philosophical, theological, and scientific education. Interdisciplinary teaching and research can be difficult to pursue in the modern academy for a variety of reasons. However, initiatives like the Project for Science and Religion at the Thomistic Institute affiliated with the Angelicum in Rome, as well as the Center for Theology and the Natural Sciences at Graduate Theological Union in the USA are very promising. Clear encouragements in this direction have come in recent decades from Popes John Paul II, Benedict XVI, and Francis, both directly addressing the science and religion field in particular, and more widely promoting integral approaches to knowledge and culture

The legacy of Ian G. Barbour is deep and wide. His typology of interaction for religion and science, his emphasis on epistemology and metaphysics, and his impact on other scholars have greatly advanced the field. While it is in no way apparent how Whiteheadian ontological principles and notions of Divine action can be reconciled with Christianity, Barbour’s lifelong quest in religion and science has generally benefitted scientists and theologians alike.


The author is grateful for the conversations and feedback related to this research from Monsignor Thomas G. Guarino, John P. Slattery, Robert J. Russell, Ivan Colage, Father Christian Irdi, Father Paweł Tomczyk, John T. Laracy, and the INTERS editorial board.


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