In this paper we use the framework of generalized probabilistic theories to
present two sets of basic assumptions, called axioms, for which we show that
they lead to the Hilbert space formulation of quantum mechanics. The key
results in this derivation are the co-ordinatization of generalized geometries
and a theorem of Sol\'er which characterizes Hilbert spaces among the
orthomodular spaces. A generalized Wigner theorem is applied to reduce some of
the assumptions of the theorem of Sol\'er to the theory of symmetry in quantum
mechanics. Since this reduction is only partial we also point out the remaining
open questions.Comment: 39 page