Scientific Revolutions
Now, what is the relationship among these
three pictures? It is clear that the
CopernicanGalileanKeplerianNewtonian revolution overthrew the Ptolemaic
system, in the sense that Ptolemy is only taught as history and never as
science. But I predict that Newton will
always be taught, because Newton’s picture is basically right  on the scale of the solar system. The scientific revolution that led to the
modern cosmos, including the early 20^{th} century contributions of
Relativity and Quantum Mechanics, have encompassed Newtonian physics with
physics that works at astronomical scales and velocities. But Modern cosmology reduces to the
Newtonian treatment for the solar system, for normal sized things on Earth, and
generally for conditions where speeds are not too high and gravitational forces
are not too great. So, we can really
only say we know that a theory is right when we know where it is wrong. Inside the boundary where the theory begins
to fail, the theory is correct (to some prearranged accuracy). Modern cosmology is undergoing an
encompassing revolution as opposed to an overthrowing revolution.
Table 1. Three Cosmologies:
Medieval, Newtonian, and Modern.
Size: R
Age: T
Center

Composition

Unifying
Ideas

God’s
role?


Medieval
Cosmos

Finite R
Finite T
Geocentric

Sublunary: Earth, Water, Air, Fire
Heavens: Ether

Circular motion
Great Chain of Being

Prime mover,
Hierarch,
Saviour


Newtonian
Cosmos

Infinite R?
Infinite T?
No center

Atoms, Void
Ether?

Deterministic mechanics
Universal gravitation

Clockmaker


Modern
Cosmos

R = 10^{28} cm
T = 10^{10} yr
Homogeneous & Isotropic

Atoms
quarks, electrons
Radiation
Dark Matter
Vacuum

Gravity = space curvature
Nondeterministic quantum theory
Evolution

Before the Big Bang?
Immanent?

Contributed by: Joel Primack and Nancy Abrams
