  We argue that a clear view on quantum mechanics is obtained by considering
that the unicity of the macroscopic world is a fundamental postulate of
physics, rather than an issue that must be mathematically justified or
demonstrated. This postulate allows a framework in which quantum mechanics can
be constructed, in a complete mathematically consistent way. This is made
possible by using general operator algebras to extend the mathematical
description of the physical world towards macroscopic systems. Such an approach
goes beyond the usual type I operator algebras used in standard textbook
quantum mechanics. This avoids a major pitfall, which is the temptation to make
the usual type I formalism 'universal'. This may also provide a meta-framework
for both classical and quantum physics, shedding a new light on ancient
conceptual antagonisms, and clarifying the status of quantum objects. Beyond
exploring remote corners of quantum physics, we expect these ideas to be
helpful to better understand and develop quantum technologies.
