  The physical foundation of the main mathematical concepts in the nonstandard
analysis theory of turbulence are presented and discussed. The basic fact is
that there does not exist the absolute zero fluid-volume. Therefore, the
corresponding physical object to the absolute point is just the uniform
fluid-particle. The fluid-particle, in general, corresponds to the monad. The
uniform fluid-particle corresponds to the uniform monad, the nonuniform
fluid-particle to the nonuniform monad. There are two kinds of the
differentiations, one based on the absolute point, another based on the monad.
The former is adopted in the Navier-Stokes equations, the latter in the
fundamental equations, the closed forms are the equations (7)-(11) in this
article, in the nonstandard analysis theory of turbulence. The continuity of
fluid is shown by virtue of the concepts of the fluid-particle and
fluid-particle in lower level. The character of the continuity in two cases,
the standard and nonstandard analysis, is presented in the paper. And the
difference in the discretization between the Navier-Stokes equations and the
equations (7)-(11) is pointed out too.
