"That one body may act upon another at a distance
through a vacuum without the mediation of anything else,
is to me so great an absurdity that,
I believe,

Every massive particle in the universe
attracts every other massive particle.
Force directly proportional to the product of their masses,
inversely proportional to the square of the
distance
between them.

Spherically-symmetrical masses attract and
are attracted as if all
their mass were concentrated
at their centers

There is no immediate prospect of identifying the mediator of gravity.
Attempts by physicists to identify the relationship between
gravitational force
and other known fundamental forces are not yet resolved.
Many attempts were made to understand the phenomena,
but there was nothing more that scientists could do at the time.

no man who has in philosophic matters
a competent faculty of thinking
could ever fall into it."