If we say yes there are four forces; that gravity is the first force;
then in order to unify those four forces; and create a working
model; of everything we must identify the cause and origin of the
motion of gravitation. Unification is the key to relativity; or
simply put; the answer as to why Newton and Einstein and really
everybody is stuck on mathematical speculation and unable to
create a working model of every-thing, including the role of the
quantum.

Once that understanding is reached; then the forces are automatically linked; through a new understanding of everything. Based on the knowledge of the origin, and cause of creation or gravitational assembly of matter:

Light is the creator; spin is the mechanism of the photonic
motion; of creation; and gravitation.

Matter thus is the expression that change or time has been created and has passed.