La fe de un físico reflexiona sobre el contenido fundamental de nuestro credo cristiano –tal como se formuló en los concilios de Nicea y Constantinopla–, haciéndolo razonable para una mentalidad actual, científica “ascendente” (que asciende desde la base fenomenológica de los datos experimentales a las más novedosas consideraciones teóricas).
Como nos dirá John Polkinghorne, esto supone tejer un tapiz en el que “si la urdimbre es el compromiso con el registro de la tradición cristiana, la trama es el compromiso con la comprensión contemporánea de nosotros mismos y del universo que habitamos”. En ese tapiz van apareciendo diversos temas de interés: nuestro ser humano con sus conocimientos y creencias, Dios y la creación, Jesucristo en la crítica histórica, en su muerte y resurrección y en la profundización cristológica, el Espíritu Santo y la Iglesia y la escatología. El conjunto es de gran valor, tanto para el teólogo que desee dialogar con nuestra actual mentalidad científica, como para el científico que desee una comprensión razonable de la fe cristiana.
Acerca del autor:
He was born in Weston-super-Mare and was educated initially in Street and then at The Perse School, Cambridge, where his contemporaries included Peter Hall. Following National Service in the Royal Army Educational Corps from 1948 to 1949, John Polkinghorne read Mathematics at Trinity College, Cambridge (alongside Michael Atiyah and James MacKay), graduated in 1952 and then earned his PhD in physics in 1955, supervised by Abdus Salam in the group led by Paul Dirac. In 1955 he married Ruth Martin, a fellow mathematician and went to CalTech as a Harkness Fellow to work with Murray Gell-Mann. After 2 years as a Lecturer at the University of Edinburgh he returned to Cambridge in 1958, and in 1968 was elected Professor of Mathematical Physics. His students included Brian Josephson and Martin Rees.
For 25 years, Polkinghorne was a theoretical physicist working on theories of elementary particles and played a significant role in the discovery of the quark. From 1968 to 1979 he was Professor of Mathematical Physics at Cambridge University, and he was elected a Fellow of the Royal Society (FRS) in 1974. He was Chairman of the Governors of The Perse School from 1972 to 1981.
He resigned his professorial chair to study for the Church of England ministry at Westcott House, Cambridge, becoming an ordained Anglican priest on Trinity Sunday 1982 in Trinity College, Cambridge by Bishop John A. T. Robinson. After five years in parochial ministry, Polkinghorne returned to Cambridge to be Dean of Chapel at Trinity Hall, 1986-1989. He then became the President of Queens' College, Cambridge, a position from which he retired in 1996. In 1997 he was made a Knight Commander of the Order of the British Empire (KBE); in 1998 he was made an Honorary Fellow of St Chad's College, Durham, and was awarded an honorary doctorate by the University of Durham; in 2002 was awarded the Templeton Prize for his contributions to research at the interface between science and religion.
Polkinghorne has been a member of the BMA Medical Ethics Committee, the General Synod of the Church of England, the Doctrine Commission, and the Human Genetics Commission. He is a current Fellow of Queens' College, Cambridge and was for 10 years a Canon Theologian of Liverpool Cathedral. He is a founding member of the Society of Ordained Scientists and also of the International Society for Science and Religion, of which he was the first President. Polkinghorne was selected to give the prestigious Gifford Lectures in 1993-4, which he later published as The Faith of a Physicist. He has an official website including a questions-and-answers page where people from all over the world send him questions on science and religion.
In 2006 he was awarded an Honorary Doctorate by the Hong Kong Baptist University as part of their 50-year celebrations. This included a public lecture on "The Dialogue between Science and Religion and Its Significance for the Academy" and an "East-West Dialogue" with Yang Chen-ning, a Nobel Laureate in Physics.
He describes his view of the world as Critical Realism and believes strongly that there is One World, with science and religion both addressing aspects of the same reality. Because scientific experiments work very hard to eliminate extraneous influences, he believes that they are thus highly atypical of what goes on in nature. He suggests that the mechanistic explanations of the world which have continued from Laplace to Richard Dawkins should be replaced by an understanding that most of nature is cloud-like rather than clock-like. He also regards the mind, soul and body as different aspects of the same underlying reality - "dual aspect monism" - "there is only one stuff in the world (not two - the material and the mental) but it can occur in two contrasting states (material and mental phases, a physicist might say) which explain our perception of the difference between mind and matter." He believes that standard physical causation cannot adequately describe the manifold ways in which things and people interact, and uses the phrase "active information" to indicate his belief that when, energetically, many possible outcomes are possible, there may be higher levels of causation that choose which occurs.
He does not have a totally untroubled faith. Sometimes Christianity seems to him to be just too good to be true, but when this sort of doubt arises he says to himself, 'All right then, deny it' and he knows this is something he could never do.
On the existence of God
Polkinghorne considers that "the question of the existence of God is the single most important question we face about the nature of reality" and quotes with approval Anthony Kenny: "After all, if there is no God, then God is incalculably the greatest single creation of the human imagination." He addresses the questions of "Does the concept of God make sense? If so, do we have reason for believing in such a thing?"
Polkinghorne is "cautious about our powers to assess coherence," pointing out that in 1900 a "competent ... undergraduate could have demonstrated the 'incoherence'" of quantum ideas. He suggests that "the nearest analogy in the physical world [to God] would be ... the Quantum Vacuum."
He suggests that God is the ultimate answer to Leibniz's great question "why is there something rather than nothing?" The atheist's "plain assertion of the world's existence" is a "grossly impoverished view of reality," he says, arguing that "theism explains more than a reductionist atheism can ever address." He is very doubtful about St Anselm's "breathtaking" Ontological Argument. "If we cannot prove the consistency of arithmetic it seems a bit much to hope that God's existence is easier to deal with," concluding that God is "ontologically necessary, but not logically necessary."
He "does not assert that God's existence can be demonstrated in a logically coercive way (any more than God's non-existence can) but that theism makes more sense of the world, and of human experience, than does atheism." He cites in particular:
The intelligibility of the universe: One would anticipate that evolutionary selection would produce hominid minds apt for coping with everyday experience, but that these minds should also be able to understand the subatomic world and general relativity goes far beyond anything of relevance to survival fitness. The mystery deepens when one recognises the proven fruitfulness of mathematical beauty as a guide to successful theory choice.
The anthropic fine tuning of the universe: He quotes with approval Freeman Dyson, who said "the more I examine the universe and the details of its architecture, the more evidence I find that the universe in some sense must have known we were coming" and suggests there is a wide consensus amongst physicists that either there are a very large number of other universes in the Multiverse or that "there is just one universe which is the way it is in its anthropic fruitfulness because it is the expression of the purposive design of a Creator, who has endowed it with the finely tuned potentialty for life. 
A wider humane reality: He considers that theism offers a more persuasive account of ethical and aesthetic perceptions. He argues that it is difficult to accommodate the idea that "we have real moral knowledge" and that "statements such as 'torturing children is wrong' are more than "simply social conventions of the societies within which they are uttered" within an atheistic or naturalistic world view. He also believes such a world view finds it hard to explain how "Something of lasting significance is glimpsed in the beauty of the natural world and the beauty of the fruits of human creativity."
On freewill and free process
Polkinghorne regards the problem of evil as the most serious intellectual objection to the existence of God. He believes that "The well-known free will defence in relation to moral evil asserts that a world with a possibility of sinful people is better than one with perfectly programmed machines. The tale of human evil is such that one cannot make that assertion without a quiver, but I believe that it is true nevertheless. I have added to it the free-process defence, that a world allowed to make itself is better than a puppet theatre with a Cosmic Tyrant. I think that these two defences are opposite sides of the same coin, that our nature is inextricably linked with that of the physical world which has given us birth."
 On kinship between science and religion
It is a consistent theme of Polkinghorne's work that when he "turned his collar around" he did not stop seeking for truth. Many of his books explore the analogies between the truth-seeking enterprises of science and religion, with a unifying philosophical outlook of Critical realism. He believes that the philosopher of science who has most helpfully struck the balance between the "critical" and "realism" aspects of this is Michael Polanyi.
He suggests that there is a cousinly relationship between the ways in which science and theology each pursue truth within the proper domains of their interpreted experience and drawing on his experience of the development of Quantum physics suggests that, in both disciplines, there are five points of cousinly relationship between these two great human struggles with the surprising and counterintuitive character of our encounter with reality:
Moments of enforced radical revision
A period of unresolved confusion
New synthesis and understanding
Continued wrestling with unresolved problems
 Criticism of Polkinghorne
The atheist philosopher Simon Blackburn published a critical review of Polkinghorne's The God of Hope and the End of the World, in which he suggested that Polkinghorne's books show "supreme contempt for philosophical reasoning and historical thinking". Richard Dawkins has said of Polkinghorne that he is one of a number of "good scientists who are sincerely religious", but says "I remain baffled ... by their belief in the details of the Christian religion."