Page Content (OCR)
105CHAPTER 20 Reality put to the test SPEAKING OF THE CONJUNCTION of the three aspects of science — theory, simulation and experiment — Jean-MarcLévy-Leblond, lecturer at the University of Nice, said: “physicists do noteven begin to cover what we want to know about reality, because speci-fying reality implies a considerable limitation of the scope of this reality,not in the least by the instruments adapted to our visual range….We areabout to witness a change in the nature of scientific knowledge” 36. This author of popular science books testified: “reality is a mental constructrather than a whole of objects.” A mental construct? In other words, weare talking about consciousness! For Emmanuel Marode, director of research at CNRS 37(note: emphasis added by the author), “simulation is based on the idea that reproducibility is a characteristic of reality [note: this is in itself a veryrestrictive and self-justifying axiom!]. In other words, we explain ourobservations by inventing entities with properties. We then visualize their behavior in the reality we try to reproduce in equations. We sub-sequently tryto solve these equations and find stable solutions. Unfor- tunately, there are numerous cases where this is not true! The obtainedsolutions behave randomly and differ greatly if we make even theslightest change to the initial data.” This testimony tells us that repro-ducibility has its limitations. We indeed need to reflect on the scale ofapproximation in which we work and the probability amplitudes ofthe diffusion matrices. The divergences (the appearance of infinities inequations) still cause a problem (except in 3D time). The truth thereforelies in the internal coherence of the theory. When it comes to reality, Klein’s testimony brings up very relevant trick questions: “how real is the reality proposed by physics when the