  Einstein action of gravity is obtained from a gauge theory, if our spacetime
was once in two folds with a double Lorentz symmetry. After the dual symmetry
breaks spontaneously, Lorentz symmetry absorbs gauge symmetry, while the gauge
field begins to drive the vierbein and the spin connection. This gauge model of
gravity has many bosons and fermions with negative norms, which will be
undetectable. The consistency of these particles with the Copenhagen
interpretation of wave functions, and their relation to the presence of dark
matter as well as the absence of antimatter in the universe are discussed.
