Review of The Road to Reality

Author: Javier Sánchez Cañizares,
Published in: yearbook Filosófico 41/2 (2008), 501-504
Date of publication: 2008

Roger Penrose, The Road to Reality. Una guide completa a las leyes del universo, discussion, Barcelona 2006, 1471 pp., 15 x 23, ISBN 10 84-8306-681-5

The Spanish translation of The Road to Reality, the most extensive work by the author of The Emperor's New Mind, is now available. On this occasion, the English mathematician does not lead us through the intricate problems of mind-brain relations, but to the exact point of our current reality knowledge based on mathematics and physics.

Penrose is a Platonist, convinced of the existence of mathematical truths independently of their discoverers. In this work he takes a journey from the most basic to the most complex mathematics (chaps. 1-16), to end up showing the subtle and admirable correspondence of this world with the physical theories that try to explain reality from its most fundamental levels (chaps. 17-34). The book will be especially savoured by those familiar with subject, but it is not a work for experts. Any reader interested in the knowledge of physical reality currently provided by the most advanced theories can get a sufficiently solid idea of it after following the author to the end.

From the scientific point of view, Penrose does not allow himself to be influenced by the fashions at research and warns us of their risks. In the final chapters of the book he moves away from superstring theories, considered the mainstream of basic physics today, to show us where a research that aims to unify the perspectives of quantum physics and relativity (twistor theory) should go. Previously (ch. 29), sample masterfully describes the incompleteness of the theories that pretend to give an interpretation of the problem of measurement in quantum mechanics and reminds us of his proposal about the essential role that the gravitational interaction would play in it: "my point of view with respect to the reduction of the quantum state is that it is really a process goal, and that it is always a gravitational phenomenon" (p. 1144). Closely related to this would be the problem of the thermodynamic singularity of the big bang (cf. pp. 975-982), due to the different thermodynamic behaviour of gravity.

The author is critical of a physics conceived as an experimentally accessible theory of reality, guided only by mathematics, with a deficit of experimental confrontation (chap. 34): to what extent does the criterion of mathematical beauty or coherence assure us of the physical relevance of new theories? However, he is also aware of the intrinsic limitations of Popper's falsifiability criterion in the case of contemporary basic science, due to the impossibility internship of carrying out refutation experiments.

From a more philosophical point of view, scattered throughout the book are some comments that reflect the basic vision that has been maturing in the scientist throughout his years at research. It is worth noting accredited specialization how, starting from the objective truth of the world of mathematics, he wonders about the objectivity of the world of beauty and morality. He sample is slightly in favour of such an objective existence, although without entering into the discussion. He recognises, however, that "in today's technological culture, it is more important than ever that scientific questions are not separated from their moral implications" (p. 67).

In line with his earlier works, Penrose is also critical of naive emergentist theories of consciousness and computational functionalism. Consciousness would not be the ultimate manager of the reduction process (R) of the wave function, being itself dependent on the existence of such a process (cf. pp. 1378-1383). Apart from moving away from any shadow of idealism, his position is in our opinion compatible with a spiritual origin of consciousness, as he himself seems to imply in the same epigraph: "it is a physically real process R which is (partially) manager of consciousness itself" (p. 1381).

His discussion of the inadequacy of the theory of evolution and the anthropic principle, from a statistical point of view, to account for the origin of life and the big bang singularity is splendid: "Life on Earth does not directly need the microwave background radiation. In fact, we don't even need Darwinian evolution! It would have been much 'cheaper', in terms of 'probabilities', to produce sentient life from the random union of gas and radiation [...]. All this simply reinforces the argument that it is wrong to look for reasons from subject above, where the right conditions of the universe are assumed to have result from some subject of initial random choice. There was something very special about the starting point of the universe" (pp. 1024-1025). However, his last reflections still seem to be indebted to a certain dialectical conception between scientific attitude and believing attitude: "it seems to me that there are two possible routes to approach this question. The difference between the two is a question of scientific attitude. We could take the position that the initial election was a 'divine act' [...] or we could look for some scientific-mathematical theory to explain the extraordinarily special nature of the big bang" (p. 1025, cf., also, p. 1011). These quotations show the existence of an unresolved basic problem in current science, with clearly metaphysical connotations, while at the same time presenting an artificial dialectic between a (possible) scientific solution and divine action. Why not keep the two attitudes and paths together?

In summary, we find ourselves before a great work, difficult to read, but indispensable for those who want to get a close look at the current status of our scientific knowledge of reality, as well as the fundamental role that mathematics plays in it. Penrose's scientific questions give rise to philosophical reflections that are not always accurate, but tremendously honest. This adds extra motivation for all those who are committed to a close dialogue between science and Philosophy, and who wish to maintain a unified vision of human knowledge.