  We recount the successful long career of classical physics, from Newton to
Einstein, which was based on the philosophy of scientific realism. Special
emphasis is given to the changing status and number of ontological entitities
and arguments for their necessity at any time. Newton, initially, began with
(i) point particles, (ii) aether, (iii) absolute space and (iv) absolute time.
The electromagnetic theory of Maxwell and Faraday introduced `fields' as a new
ontological entity not reducible to earlier ones. Their work also unified
electricity, magnetism and optics. Repeated failure to observe the motion of
earth through aether led Einstein to modify the Newtonian absolute space and
time concepts to a fused Minkowski space-time and the removal of aether from
basic ontological entities in his special theory of relativity. Later Einstein
in his attempts to give a local theory of gravitation was led to further modify
flat Minkowski space-time to the curved Riemannian space time. This reduced
gravitational phenomenon to that of geometry of the space time. Space-time,
matter and fields all became dynamical. We also abstract some general features
of description of nature in classical physics and enquire whether these could
be features of any scientific description?
