Besides two fundamental postulates, (i) the principle of relativity and (ii
) the constancy of the speed of light in all inertial frames of reference,
the special theory of relativity uses another assumption. This other assump
tion concerns the Euclidean structure of gravity-free space and the homogen
eity of gravity-free time in the usual inertial coordinate system. Introduc
ing the primed inertial coordinate system, in addition to the usual inertia
l coordinate system, for each inertial frame of reference, we assume the Eu
clidean structures of gravity-free space and time in the primed inertial co
ordinate system and their generalized Finslerian structures in the usual in
ertial coordinate system. We combine the alternative assumption with the tw
o postulates (i) and (ii) to modify the special theory of relativity. The m
odified special relativity theory involves two versions of the light speed,
infinite c' in the primed inertial coordinate system and finite c in the u
sual inertial coordinate system. It also involves the c'-type Galilean tran
sformation between any two primed inertial coordinate systems and the local
ized Lorentz transformation between two corresponding usual inertial coordi
nate systems. Since all our experimental data are collected and expressed i
n the usual inertial coordinate system, the physical principle is: the c'-t
ype Galilean invariance in the primed inertial coordinate system plus the t
ransformation from the primed inertial coordinate system to the usual inert
ial coordinate system. This principle is applied to a reformulation of mech
anics, field theory and quantum field theory. Relativistic mechanics in the
usual inertial coordinate system is unchanged, while field theory is devel
oped and divergence-free. Any c'-type Galilean-invariant field system can b
e quantized by using the canonical quantization method in the primed inerti
al coordinate system. We establish a transformation law for quantized field
systems as they are transformed from the primed to the usual inertial coor
dinate system. It is shown that the modified special relativity theory, tog
ether with quantum mechanics, leads to a convergent and invariant quantum f
ield theory, in full agreement with experimental facts. The formulation of
this quantum field theory does not demand departures from the concepts such
as local Lorentz invariance in the usual inertial coordinate system, local
ity of interactions, and local or global gauge symmetries. (C) 2001 Elsevie
r Science Ltd. All rights reserved.