FOUNDATION FOR FISHER-INFORMATION-BASED DERIVATIONS OF PHYSICAL LAWS

principle of extreme physical information (EPI) places physics on an i nformation-theoretic footing. It yields many of the fundamental wave e quations of physics (of Klein-Gordon, Dirac, etc.). EPI is based upon the measurement of particle four-vectors theta(n) with random errors x (n), n = 1,...,N. This leads to an additive Fisher information form wh ose extremization provides the derivations. However, the model measure ment procedure was, in the past, overly restrictive: the real and imag inary parts q(n)(x), n = 1,...,N of the probability amplitude function s for the fluctuations were required to have nonoverlapping support re gions. Here we rederive the requisite information form without this re striction. Our model measurement procedure is simply the efficient col lection of four-data, that is, N independent measurements of four-coor dinates of particles of the field. In effect, each measurement defines a different degree of freedom q(n)(x) of the scenario.