Mathematics of energy and 1800s decisions

What is light?  No one knows, yet the "laws" of mathematics and physics treat all energy as equivalent.  It originates with the "conservation of momentum" which appears to be a valid "law".

All mathematical formulas describing energy derive from Newton's kinetic formula kg*m/s^2.  Was it not presumptuous to rewrite the rules of mathematics based on mid-1800s science?  "Conservation of energy" was a mid-1800s assumption on an extension of momentum.  Today, physicists are still arguing over Maxwell, Poisson, and Einstein.

Why is the solar constant expressed in W/m^2 and not in newtons? Watts is an expression of joules which is an expression of newtons with meters, so why is that not mathematically normalized?

Further, why were all the rules of mathematics governing energy rewritten in the mid-1800s?