Rumors of transcendency in astrophysics

by Hubert Reeves, Astrophysicist, Director of research

A cautious but insightful article on the question of meaning in astrophysics.

The scientific methodology was initiated two thousand years ago in Ancient Greece and elaborated in its present form during the Renaissance. It is founded on the definite will to look for answers on questions about nature in the frame of nature itself. To abstain from the intervention of transcendent, supernatural or religious elements. we ask : could the results of an activity based on this methodology paradoxically lead us out of the field of science and open the doors to some kind of trancendency ? The problem is not new. The developments of biological sciences in the 18th and 19th centuries have brought to light a certain number of intriguing “coincidences”. For instance the sensibility of the eye precisely adjusted to the maximum of intensity of the solar luminous spectrum. Or the length of the trunks of butterflies well adjusted to the depth of the corollas of the flowers they pollenate. For many decades such coincidences were seen as manifestations of a “project” in nature. The study of the clock would haverevealed the existence of a clockmaker. Science would have discovered God in its nets. However this phase of “concordance” between science and religion did not last long. In the second part of the 19th century, thanks to the work of Charles Darwin, these coincidences were shown to be no miracle but explainable in terms of biological evolution involving selection processes.

A new chapter in relation with this problem is presently being written in the field of astrophysics. The combined investigations of physics and astronomy have uncovered a number of coincidences at least as intriguing as those of biology in the past centuries. I will describe a few, but there are many more. The numerical values of the coupling constants of the physical interactions are particularly important examples. It can be shown that different values (ever so slightly different) would have given rise and led to the evolution of sterile universes – universes without complexity, and without life. Another example is the ratio of the mean number of photons to protons well adjusted to the formation of long lasting galaxies and stars. Yet another one is the numerical value of the energy (and spin and parity) of the second excited state of the carbon nucleus in comparison to the mass of three helium nuclei. Without this happy coincidence, the carbon atoms – that are crucially important for the construction of biological structure – would have been extremely rare. (more on this in the book “Before the Beginning” by Martin Rees).

Various attempts have been made to interpret these coincidences in a synthetic frame of thought usually called the “anthropic principle”. (I personally prefer the less anthropocentric appellation “principle of complexity) . Each author has his own formulation of this principle which are usually regrouped in a weak and a strong version. The weak version simply states that ” the universe is ruled by laws which are well suited for the appearance of life and consciousness”. In the strong version, with a philosophical connotation , these coincidences are the manifestation of a “project ” in the universe. “Somewhere the universe knew that we were coming” (Freeman Dyson).

Again the possibility of “transcendency ” is a very moot problem in the field of science. Its exclusion has been fundamental in the progress of scientific knowledge. Here, just as in the pre-Darwinian times, we face its possible reintroduction. Inspired, without doubt, by the success of the Darwinian approach, some authors have tried to explain these various coincidences in terms of selective processes occurring in the first moments of the universe. So far the results are not very convincing. More interesting is the “multiverse” hypothesis. There would exist a large number of universes, similar to ours, but where the numerical values of many properties of matter would differ from one universe to another. Only those universes which have values closely similar to ours would have given rise to complexity, intelligence and conscience. The other remained sterile and nobody there asks any questions.

We note first that the hypothesis of the existence of such universes is nowhere in conflict with our present knowledge of physics. In fact it would seem to emerge quite naturally from the present theory of elementary particles. The fact that in this theory many physical parameters acquire their numerical values during early events called “phase transitions” (implying spontaneous breaking of various symetries) introduce an essential element of contingency in the determination of these values. There is no known reason why they should be the same everywhere. It would seem that the only weak point of this argumentation is that we have no observational proof of the existence of such universes. It is based on purely theoretical arguments.

But, after all, is this point so weak ? Historical examples of objects which were first proposed on the basis of theoretical arguments and later observed are numerous. Neutrinos and black holes are probably the best known. Other presumed objects are still lacking : for instance the Higgs bosons ( in relation with the electroweak unification) and the tachions (particles traveling faster than light). The Higgs bosons may soon be discovered, but for the tachions no one can tell. Nevertheless, few physicists would go to the extreme of stating that any object allowed by the laws of physics should necessarily exist. Especially if we do remember that physics is unfinished and , in fact, a rapidly evolving body of knowledge. In a nutshell, the multiverse hypothesis avoids the ghost of transcendency by assuming the existence of sextillions of unobserved universes. How good is the exchange ?

I have , in many occasions , discussed these points with scientific colleagues. I have tried to obtain their personal reaction in relation with the anthropic principle and, in particular, in relation with the multiverse hypothesis. The reactions are astonishingly varied. On one extreme we find an enthousiastic acceptation of the anthropic principles in its strongest version, often, quite expectedly, amongst religiously bent scientists. Here we are reminded of an event taking place in Vatican some decades ago when Georges Lemaître warned the Pope Pius XII against simplistic religious interpretation of the theory of the Big Bang.

On the other end of the spectrum we find from many scientists a despising reject of even the weak version seen as an empty statement , tautological and devoid of interest. These opponents , often at the fringe of irritation , are found amongst people prone toward materialistic philosophy but also ,curiously enough amongst devout believers of various religious persuasions. “Religion is a matter of faith ; we do not need science to believe” . In my opinion this wide diversity of reactions amongst competent scientists illustrates the important component of personal sensibility affecting judgement in such a matter. Ideas have “taste”. It important for a scientist to recognize the component of subjectivity in the choice of his opinions and options in domains which are not devoid of potential metaphysical implications. In particular those neihboring the problems of origins ( of the universe, of life, of consciousness). His lucidity consists in asking himself why does he prefer that interpretation over an other one.

One should keep an open mind and leave interesting questions unanswered until a satisfactory answer has emerged (perhaps never…) ,such as the darwininan answer for biology. Perhaps the multiverse answer is the correct interpretation of the anthropic principle. Perhaps not. We must keep open the possibility that this principle could lead us to unknown territories, far richer than the conventional debates on the existence or not of a clockmaker. “There are more things in the world than all your philosophies” wrote Shakespeare . We should not neglect any chance to discover them. Personnally , and I recognize it is only a matter of taste, I would be disappointed if the present rumors of transcendancies turned out to be just rumors.