1. Our aim is not to examine here Heisenberg's philosophical propensity, which was of much service in dealing with the abstract concepts of quantum mechanics. Instead, we shall discuss some of his ideas regarding existence and cognition and the breakthroughs beyond the safe science he dealt with, by reference to the image of the material world, of the whole existence as outlined in the foregoing chapters. As a theory founder and a scientist well acquainted with the quantum world, Heisenberg sought to grasp the profundities of this world down to the unity of the principles of existence. He could not however consider the effects of automata, of neurocybernetics, or of the living beings and the information concept, given that these questions became pre-eminent in contemporary scientific thought only after the foundation of quantum mechanics. While noting Heisenberg's concern for the biologic/atomic connection, which is used as a reference term to inquire into the comprehensive correlations in the world (p. 186), let us observe that, finally, the data furnished by chemists and biologists "flood ... into the wider field of atomic physics" (p. 198). Nevertheless, in the final chapter of his book ("Is physics an ended science ?"), in which he seeks to derive the sole principle at play beyond the elementary particles, the author wonders if the discovery of such a principle would not permit us to cognize the whole world and, hence, physics would no longer have anything to tell us. However, Heisenberg had unexpectedly observed in 1970 that if such a principle were found, it would only cover a part of the world reality. He subsequently approached the implications of such a discovery in the biological and living realms (p. 320). He held that although "all biological objects consist in elementary particles", the concept of life itself "does not appear in this idealization of a unified theory of particles which would be a formula of the Universe". Heisenberg is in search of a more comprehensive theoretical approach that should bring the physical closer to the life phenomenon, to the biological. This explains why he holds that physics cannot end with the unified theory of elementary particles, for mathematics, the information theory and philosophy will conjoin the work of physics: "in the future, it will be frequently difficult to decide whether in the case of a scientific advancement we shall have a progress in physics, in the information theory or in philosophy, whether physics extends in biology or whether biology is making increasing use of the methods and formulation pertinent to physical problems" (p. 321). These lines, written on the last page of his book, are no doubt an intuition of what science will become under the strenuous human search to find its unity. This comes in the aftermath of Heisenberg's other intuitions of the depth of the quantum world and of the profundities of the material world itself, where correlations with the information and life must be at play. In developing his abstract theories, Heisenberg found support in Plato's and Kant's ideas. This may partly explain why he held that in terms of philosophy, the scientist is first interested in problem formulation and only second in the answers (p. 14). The problem formulation in philosophy is worthy, Heisenberg says, inasmuch as it is a fertile ground for the development of the human thought.

However, as Heisenberg righteously observed, a new problem should be posed in philosophy, along the lines he himself intuited. This is exactly what we are trying to do in this book. That is why the concepts and the ideas given in this book and those of Heisenberg's may be subject to confrontation. In so doing, we shall consider the materiality of the whole existence as a safe gain of the human thought. No theoretical, experimental or spiritual grounds could be brought to invalidate the truth of this statement. We have however to employ first philosophical concepts and then the safer exertions of science in order to inquire into the profundities of the world, confident as we are that such an inquiry is possible. Part of our inquiry may turn out to be of a purely experimental nature without necessarily resorting to a scientific department of knowledge, the mathematically rided departments in particular. This will by no means rule out any science, however little developed it may be in the beginning.

2. One of Heisenberg's basic ideas is that a thrust into increasingly deeper strata of matter is mentally associated with abstractions increasingly far from the immediate intuition. This idea is grounded in Plato's and Kant's theories. With Heisenberg, and similarly with Kant, nature must be questioned by means of theoretical concepts, or abstract models built in our mind. The question arises why these highly abstract mathematical concepts comply with nature. Following a discussion he had with Niels Bohr, who, like Faraday, revered the physical, intuitive grasp of phenomena, and given the impossibility to understand quantum physics with the aid of immediate intuitive concepts, Heisenberg confessed: "On this night-starred route^**, I thought of the almost obvious idea that one should perhaps just postulate the fact that nature permits only such experimental situations that might be described against the mathematical scheme of quantum mechanics" (p. 62-63).
According to Heisenberg, the profundities of nature could be grasped by passing form abstraction to abstraction, under its mathematical form, which relies particularly on the harmony of the symmetry forms. With Heisenberg, abstraction is to find the unity of the world. He wonders if Plato is not right in believing that abstraction itself is the ground of the world. Heisenberg declares himself to revere Plato's idealism, to the detriment to Democritus' materialism (p. 243), as modern physics would have indubitably decided in favour of Plato: "Because the smallest units of matter do not actually represent physical objects in the ordinary sense of the word, and are instead forms, structures, or - in the sense of Plato - ideas about which we can speak unambiguously in the mathematical language alone" (p. 240). Heisenberg finds mathematical symmetries in terms of the smallest units of matter. For him, the question is whether the elementary particles in-themselves exist in space and time or whether the question can be raised in these terms (p. 113, 139). "The concepts of space and time must be themselves re-formulated (p. 167); the world is not really as we used to think with the aid of ordinary concepts" (p. 170).

What Physics, Informationand the Living have in Common 24