My dear Professor Odifreddi, (...) I would like to thank you for having tried in great detail to engage with my book and thus with my faith; this is largely what I had intended in my speech to the Roman Curia at Christmas 2009. I must also thank you for the fair manner in which you treated my text, sincerely trying to do it justice.

My judgement of your book as a whole is, however, rather mixed in itself. I read some parts of it with enjoyment and profit. In other parts, however, I marvelled at a certain aggressiveness and recklessness of the argumentation. (...)

Several times, she points out to me that theology would be science fiction. In this regard, I am amazed that you nevertheless consider my book worthy of such detailed discussion. Allow me to propose four points on this matter:

1. Is it correct to say that 'science' in the strictest sense of the word is only mathematics, whereas I learnt from you that here too a distinction should be made between arithmetic and geometry. In all specific subjects, scientificity has its own form each time, depending on the particularity of its object. The essential thing is that it applies a verifiable method, excludes arbitrariness and guarantees rationality in the respective modes.

2. At the very least, it should recognise that, in the historical sphere and in that of philosophical thought, theology has produced lasting results.

3. An important function of theology is to keep religion bound to reason and reason to religion. Both functions are of essential importance to humanity. In my dialogue with Habermas, I showed that there are pathologies of religion and - no less dangerous - pathologies of reason. Both need each other, and keeping them continuously connected is an important task of theology.

4. Science fiction exists, on the other hand, within many sciences. What you expound on the theories about the beginning and end of the world in Heisenberg, Schrödinger, etc., I would designate as science fiction in the good sense: they are visions and anticipations, in order to arrive at true knowledge, but they are, in fact, only imaginations with which we try to approach reality. There is, after all, science fiction in a big way even within the theory of evolution. Richard Dawkins' The Selfish Gene is a classic example of science fiction. The great Jacques Monod wrote some sentences that he himself will surely have included in his work only as science fiction. I quote: 'The appearance of tetrapod vertebrates ... originates precisely from the fact that a primitive fish 'chose' to go and explore the earth, on which it was, however, unable to move except by jumping awkwardly and thus creating, as a consequence of a change in behaviour, the selective pressure thanks to which the robust limbs of the tetrapods would develop. Among the descendants of this daring explorer, this Magellan of evolution, some can run at speeds in excess of 70 kilometres per hour..." (quoted in the Italian edition Il caso e la necessità, Milan 2001, p. 117 ff.). 

In all the issues discussed so far this is a serious dialogue, for which I - as I have already said repeatedly - am grateful. Things are different in the chapter on the priest and Catholic morality, and still differently in the chapters on Jesus. As for what you say about the moral abuse of minors by priests, I can - as you know - only take note of this with deep consternation. I have never tried to disguise these things. That the power of evil should penetrate to such an extent into the inner world of faith is for us a suffering that, on the one hand, we must endure, while, on the other hand, we must at the same time do everything possible to ensure that such cases do not happen again. Nor is it any comfort to know that, according to research by sociologists, the percentage of priests guilty of these crimes is no higher than in other comparable professional categories. In any case, one should not ostentatiously present this deviation as if it were a filth specific to Catholicism.

If it is not permissible to remain silent about evil in the Church, one must not, however, remain silent either about the great luminous wake of goodness and purity that the Christian faith has traced down the centuries. We must remember the great and pure figures that the faith has produced - from Benedict of Norcia and his sister Scholastica, to Francis and Clare of Assisi, to Teresa of Avila and John of the Cross, to the great Saints of charity such as Vincent de Paul and Camillus de Lellis, to Mother Teresa of Calcutta and the great and noble figures of 19th century Turin. It is also true today that faith drives many people to selfless love, service for others, sincerity and justice. (...)

What you say about the figure of Jesus is not worthy of your scientific rank. If you pose the question as if nothing is known about Jesus and nothing can be ascertained about him as a historical figure, then I can only strongly urge you to become a little more historically competent. I recommend to you for this especially the four volumes that Martin Hengel (an exegete from the Protestant Theological Faculty in Tübingen) has published together with Maria Schwemer: it is an excellent example of historical accuracy and extensive historical information. In the face of this, what you say about Jesus is rash talk that you should not repeat. That much has also been written in exegesis that is not very serious is, unfortunately, an indisputable fact. The American seminar on Jesus that you cite on pages 105 ff. only confirms once again what Albert Schweitzer had noted about Leben-Jesu-Forschung (Research on the Life of Jesus), namely that the so-called 'historical Jesus' is mostly a mirror of the ideas of the authors. Such unsuccessful forms of historical work, however, in no way undermine the importance of serious historical research, which has brought us true and reliable knowledge about the proclamation and the figure of Jesus. 

(...) Furthermore, I must emphatically reject your claim (p. 126) that I have presented historical-critical exegesis as a tool of the antichrist. In dealing with the account of Jesus' temptations, I have only taken up Soloviev's thesis that historical-critical exegesis can also be used by the antichrist - which is an indisputable fact. At the same time, however, I have always - and in particular in the preface to the first volume of my book on Jesus of Nazareth - made it abundantly clear that historical-critical exegesis is necessary for a faith that does not propose myths with historical images, but claims true historicity and must therefore also present the historical reality of its claims in a scientific manner. That is why it is not even correct for you to say that I would only be interested in meta-history: on the contrary, all my efforts are aimed at showing that the Jesus described in the Gospels is also the real historical Jesus; that it is history that really happened. (...)

With the 19th chapter of your book we return to the positive aspects of your dialogue with my thinking. (...) Although your interpretation of John 1: 1 is far removed from what the evangelist intended, there is nevertheless a convergence that is important. If you, however, want to replace God with 'Nature', the question remains, who or what this nature is. Nowhere do you define it and it therefore appears as an irrational deity that explains nothing. Above all, however, I would still like to point out that in your religion of mathematics three fundamental themes of human existence remain unconsidered: freedom, love and evil. I am astonished that you with a single mention dismiss freedom, which has been and is the core value of the modern age. Love does not appear in your book and there is no information about evil either. Whatever neurobiology may or may not say about freedom, in the real drama of our history it is present as a determining reality and must be taken into account. But your mathematical religion knows no information about evil. A religion that leaves out these fundamental questions remains empty.

My dear Professor, my criticism of your book is harsh in parts. But frankness is part of dialogue; only in this way can knowledge grow. You have been very frank and so you will accept that I am too. In any case, however, I very much welcome the fact that you, through your confrontation with my Introduction to Christianity, have sought such an open dialogue with the faith of the Catholic Church and that, despite all the contrasts, there is no lack of convergence in the core area.

With cordial greetings and all good wishes for your work.

[Pope Benedict, article in La Repubblica 24/09/2013]