We argue that the non-observability of the spontaneous breakdown of Lorentz
symmetry (SBLS) caused by the vacuum expectation values of vector fields c
ould provide the origin of all internal symmetries observed. Remarkably, th
e application of this principle to the most general relativistically invari
ant Lagrangian, with arbitrary couplings for all the fields involved, leads
by itself to the appearance of a symmetry and, what is more, to the massle
ss vector field(s) gauging this symmetry. A simple model for the SBLS based
on massive vector and real scalar field interactions is considered; it is
found that spontaneously broken gauge symmetries could also appear, when SB
LS happens and is required to be physically unobservable. (C) 2001 Elsevier
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