  Maintaining the relativity of all motion, especially rotational motion, Mach
denied the existence of absolute motion and absolute space. He maintained the
equivalence of the Ptolemaic and the Copernican systems and the equivalence of
a fixed bucket in a rotating universe with the converse. An analysis of the
Foucault pendulum shows that there cannot be a fixed bucket in a rotating
universe. Also, Mach's views violate the physics he espoused: non-inertial
experiments, e.g. stellar aberration and electromagnetic effects, distinguish
between a rotating bucket in a fixed universe and the converse, between the
Copernican and the Ptolemaic systems, and establish that one cannot ascribe all
observations solely to relative motion between a system and the universe.
