  We present a derivation of Born's rule and unitary transforms in Quantum
Mechanics, from a simple set of axioms built upon a physical phenomenology of
quantization. Combined to Gleason's theorem, this approach naturally leads to
the usual quantum formalism, within a new conceptual framework that is
discussed heuristically in details. The structure of Quantum Mechanics, from
its probabilistic nature to its mathematical expression, appears as a result of
the interplay between the quantized number of "modalities" accessible to a
quantum system, and the continuum of "contexts" that are required to define
these modalities.
