In Science and Theology, John Polkinghorne presents a vision of science and theology that allows them to interact with one another faithfully. While both have different objects of study and different methods of study, he believes they are cousins, specifically because of a similar philosophical approach to their study which he calls “critical realism” (20). He believes both are incapable of arriving at absolute truth (16, 20). Yet both are capable of coming closer to the truth, always refining their understanding in a community of people studying the same subject (16-17, 20). He also describes both as “circular”. He says of science: “If entities behave in the way that theory supposes, then that is what is happening in this experiment; if this is what is happening, then this is the appropriate theory to describe what is going on” (17). He says of them both: “Both disciplines are concerned with the search for motivated belief and their understandings originate in interpreted experience. The necessary circularity involved in this process is no surprise or embarrassment to theology” (20). Because both describe complex subjects with increasing accuracy, but never fully arriving at absolute knowledge, they both must be explained through “selective simplification” through models, metaphors, and symbols (22-24).

Polkinghorne continues in his second chapter to explain recent scientific developments. He begins by describing quantum theory and compares it to classical physics. The key difference between the two is the principle of superposition. Superposition is demonstrated by the classic double split experiment. In it, particles are thrown at a barrier containing two slits. The particles strike a screen behind the slits and they form a wave pattern across the screen backdrop (26 – 27). The experiment shows the effect measurement has on reality. The question scientists continue to grapple with is whether or not the measurement affects the particles, shows one possible outcome in this universe, or describes reality (28 – 29). Polkinghorne continues with the field of cosmology. Specifically, he walks the reader through the anthropic principle. “A universe capable of evolving carbon-based life is a very particular universe indeed, ‘finely tuned' in the character of its basic physical processes, one might say” (36). Cosmology also describes evolution as a process of both chance and necessity in order to create a finely tuned universe ready for life (39 – 40). Chaos theory explains that the universe is "sensitive to small disturbances” (41). Complexity explains that the world steadily becomes more and more complex (44).

Polkinghorne then turns to a key intersection between science and theology: humanity. He describes several scientific attempts to explain consciousness. The first he calls “functionalism" (58). Functionalism supposes “the essence of the matter to lie in the processing of information, turning the input of signals from the environment in the output of motor activity of various kinds” (58). However, functionalism fails to explain who programs this biological computer or why consciousness is important to survive (59 – 60). Another proposal is called emergence. Emergence suggests "that consciousness is an emergent property of biological systems of a sufficient degree of complexity” (60). However, this “fails to face the huge gap between physical talk of neural networks, however sophisticated such talk may become, and the simplest mental experience, say of seeing red” (61). Others suggest that quantum physics can help explain the workings of the brain, but the brain is not an atomic system. Rather, it is "like an immensely complicated integrated macroscopic system” (62). All in all, Polkinghorne demonstrates that while science explains some functions of the brain, it is unable to fully explain consciousness or humanity's existence as psychosomatic unities (62). He then turns to Christianity's explanation of humanity as fallen. He interprets Genesis 3 as a myth because scientific evidence suggests “earthquakes, volcanoes, hurricanes, animal death – all antedate the appearance of humanity on earth by hundreds of millions of years” (64). Such an interpretation has by no means been the majority Christian interpretation. Polkinghorne, however, believes his understanding of Genesis 3 and scientific evidence for evolution fit the view of St. Iraneaus, which saw “ primeval innocence as the innocence of childhood and it told the story of human development in terms of a growing up into a not-yet-attained maturity. In these terms, the fall is more like the stormy times of adolescence” (64).

In the following chapter, Polkinghorne explores the limit of scientific inquiry and explains what relationship God could have to recent scientific inquiries. He begins with a common definition of God as “a person, omnipotent, omniscient, and perfectly free” (66). However, in describing God we are dealing with a top–down definition, while science is a bottom–up process (68). What evidence is there for a God like this? Polkinghorne continues with a description of Christian natural theology. While natural theology has had various forms, most recently, it has been interested in the question “why is there something rather than nothing?” (71). This question contains two further questions, namely, “why are we able to study unintelligible world?” and “why is the universe so special?” (72). There are two possible explanations to the second question. Either there are many disconnected worlds or there is a creator (75). Of all scientific fields, biology is, perhaps, the least open to a creator, namely, because they deal with mechanistic biological processes (77). Yet, the dynamic of chance and necessity still leaves room for a creator. "Necessity is seen as the Creator’s endowment of creation with the potential for fruitful development. The laws of nature are so designed that they will lead to the coming-to-be of self–conscious and God–conscious beings” (79). Polkinghorne concludes by pointing out a theological ignorance among scientists. Creation is not an explanation of how things came to be, but the “ontological origin” of creation, namely that God is the cause of creation and continues to work through creation (79 – 80).

Here, Polkinghorne comes to a weakness in his thought. He himself notes this when he says, “the idea should amount to more than merely a pious gloss imposed on a fundamentally natural evolutionary story" (84). However, as he attempts to explore various views of divine action, he finds flaws in them all and never seems to settle on one. From a theological perspective, the subject of divine action is already complex, but Polkinghorne also adds his scientific considerations. His discussion on miracles illustrates the complexities on both sides hie tries to navigate. He believes miracles are difficult for both science and theology. In science, it is impossible to observe a one-time occurrence, but years of observation limits the possibility of such occurrences (92). However, he also believes theology struggles with miracles. God cannot be seen as a "celestial conjurer”, but miracles must show more of how the divine interacts with creation (92). Polkinghorne tries to present a view of the world that sees God as both the divine cause, but also leave freedom for creation's own act (94), but he does not propose how these two sides should be held together.

Polkinghorne then applies his critical realist interpretation to Christian theology. He says about the Bible: “the Bible certainly contains truth about God; it certainly has moved many people to lives of spiritual depth and the deeds of great generosity; it certainly is an indispensable symbolic resource of Christian discourse. Yet it also contains unedifying material concerned with acts of genocide trade as divine commands, ventral curses upon enemies, sadistic symbols of everlasting torture. Any adequate and honest approach the Bible will have to take account of all these features” (99). He also applies his approach to the resurrection of Christ. He believes that all of the evidence points up to the resurrection, namely the change in the disciples, the early accounts of the resurrection, the common theme of the empty tomb, and the worship practices of the Christian church (105 – 106 ). He performs a similar method with Christology. He argues that Chalcedonian Christianity explains common features of Christian faith. Jesus must be divine and human because in his death and resurrection he identifies with humanity and with the power of God. He is also "the meeting place between the life of God and the life of humankind, the bridge by which creator and creation are joined together” (111).

Polkinghorne then applies his critical realist method to inter-religious dialogue. He affirms a view of inclusivism. He says: “inclusivism is naturally allied to critical realist understanding of theology: acknowledging the universal presence of encounter with the sacred ; seeking to understand its different modes of expression and description, while recognizing that each tradition and community must view reality from a cultural perspective; knowing that interpretation and experience intertwine, yet believing that behind it all is an actual Reality of which we may hope to gain verisimilitudinous understanding; trusting of this Reality is such that an understanding of it is, at least to some degree, attainable by humankind" (125). Finally, Polkinghorne suggests science could be the common denominator religions use for interfaith dialogue (125).

Polkinghorne concludes his work with a brief discussion of ethics. Ethics seeks to put limits on scientific inquiry (129) to protect just practices and the sustainability of creation (133). Religion plays a key role in ethics. "The religious believer…can offer ground for their adoption which explains the origin of these moral institutions. The Earth's resources are not there to be grasped for our present satisfaction, heedless of the needs of others present or future, because the Earth itself is not ours but God’s. We are creatures who receive nothing that is not given to us. Creation exists solely because of divine generosity, for creatures to share and to enjoy and to hand on. Human beings are the stewards of terrestrial creation, not its owners. The most significant aspect of the interaction between science and theology is the latter's provision of the grounds for the ethical guidelines within which the great endeavor of science and technology can only rightly be pursued" (133).

All in all, Polkinghorne provides a helpful integration of science and theology based on a model of critical realism. However, at the end of the book, the reader is left wondering, “who determines the standards of critical realism?” At times, particularly in regards to interpreting Old Testament passages, Polkinghorne make suggestions outside of traditional interpretation without giving clear reasons other than that he is a critical realist. At times, the reader is left feeling that Polkinghorne is the authority without other grounds for some of his conclusions. While Polkinghorne leaves questions regarding the foundations of critical realism, he effectively demonstrates how this model can foster dialogue between science and theology.