It is said that on one occasion, when the French astronomer, physicist and mathematician Pierre-Simon Laplace gave a copy of one of his works to Napoleon, the latter commented: "I have been told that in this great book you have written on the system of the world there is no mention of God, its creator". To which Laplace replied: "I have not needed that hypothesis".

For centuries, scientific discoveries seemed to run counter to the belief in God. Science was pushing back religion and the technological development made useless the need to turn to a God to explain and solve human problems. Those who held a believing position experienced a certain inferiority complex with respect to rationalism. Materialism became intellectually dominant.

The book God. Science. The evidence. The dawn of a new revolution. A bestseller in France with more than 250 000 copies sold. Its authors, Michel Yves Bolloré and Olivier Bonnassies, argue that materialism is a belief like any other and that the current state of science does not disprove the existence of God, but rather test.

According to these authors, despite the remaining uncertainty about the nature of the subject and dark energy, the coherent data currently available to us, if the laws of nature do not change with time, show that the only possible end of the universe is its thermal death, a consequence of the application of the second principle of thermodynamics.

The hypothesis that today gathers the widest consensus is that the Universe is in an accelerated expansion. According to this, in about 10¹⁰⁰ years the complete thermal death of the universe will take place, extremely dilated in a maximum expansion in which it will reach the maximum entropy and will be the end of all thermodynamic activity.

What they call the "Dark Era" will begin, in which there will be only photons in a gigantic space that will tend to absolute zero. The universe, therefore, is neither static nor eternal and is in evolution.

And if it has an end, it must have had a beginning. The standard Big Bang model , an expanding universe with a concrete beginning 13.8 billion years ago, has been repeatedly verified and confirmed despite failed attempts to develop other models.

The universe, therefore, is not something fortuitous, disordered and random, but emerges from an adjusted process in which each element appears progressively. Everything emerges from a "primitive atom". Before there was no time, no space, no subject. There was nothing.

Time, space and subject arise at a specific moment. Infinity, therefore, is only a concept. The "before" would be outside experimental science. This hypothesis, the most coherent and the one that currently enjoys the greatest consensus, generates other questions: if the universe is not eternal, what was there before? Nothingness, no time? How does something arise from nothing? And, above all, why does it arise? For the authors this is a test of the existence of a creator God.

Although there are other interpretations or hypotheses -such as cosmic inflation, the universe without edges, superstring theory, inflationary models, an eternal and cyclic multiverse with ten or more dimensions arising from pre-existing laws...- they are extremely complex, highly speculative and unlikely to be verified, although they are an interesting intellectual and scientific exercise.

The book also includes a thought-provoking chapter on the ideological persecution of Big Bang scientists.

In cosmology, fine-tuning the universe means that the conditions that allow life in the universe can only occur when certain fundamental constants are in a very narrow range of values. Thus, if any of these constants were slightly different, the universe, subject and life would not be possible.

The universe appears as a "whole assembly", a mechanics with incredible precision in which each stage depends on improbable adjustments and complex, indispensable gears that fit together to allow the existence and functioning of the whole. It is what some have called the anthropic principle, that seemingly incredible series of coincidences that allow our presence in a universe that seems to have been perfectly prepared to guarantee our existence. From the force of gravity, the electromagnetic force, the speed of light, Planck's constant, the charge and mass of the electron and proton...

According to this, it is difficult to argue that the universe, the subject and the leap from the inert to the living have arisen from chaos, or that chance and probability are the only cause. Materialism and chance remain a challenge and alone cannot explain all of reality.

In my opinion, all these arguments are not demonstrations of the existence of God. Science can no more prove the existence of God than it can prove that God does not exist. It is not necessary for science to support faith.

To explain the world around us it is not necessary a direct intervention of God, what is usually called the "God of the gaps". When there is a "gap", something I do not understand or for which I have no scientific explanation, I call upon God who with his magic finger fills the gap. A very attractive "hypothesis" but perhaps not essential. It is good to remember here the quotation "the Bible does not tell us what heaven is like, but how to go to heaven".

But what the authors do show is that science does not necessarily distance us from God and that believing in God is something "reasonable", that for a man or woman of science in plenary session of the Executive Council it makes sense to be a believer. Faith is not irrational, it is not an "add-on": it is also a consistent way of understanding reality.

Science and faith complement each other in their ultimate goal, which is the knowledge of the truth of the world and of the human being. Science will question us and give us answers (or at least it will try to) about how things are. And faith will give some of us the reason, the meaning, the why. But they are not independent territories, but complementary.

For those of us who have faith, it is a stimulus to continue investigating passionately, because the more we know about the world around us, the more we know about God. What if there is a contradiction between what science tells me and what faith suggests to me, subject ? The reality is one, those apparent contradictions are a stimulus to continue studying and investigating more.

As Robert W. Wilson (award Nobel Prize in Physics 1978) writes in the prologue of the book: "A superior being could be at the origin of the universe; although this general thesis does not seem to me to be a sufficient explanation, I accept its coherence". The statement "science does not disprove the existence of God, but rather test" proposes an essential discussion without insults, degradations or cancellations. Thinking things through does not have to mean discarding "the hypothesis of God".