Parameter free Mathematical Models: Einstein's Ideal + Kant's a priori

A mathematical model/equation without parameters, like viscosity in Navier-Stokes equations for incompressible fluid flow, can be used to make a priori predictions of physical reality without relying on some measurement of any parameter like viscosity. This is the ideal model of physics according to Einstein, which fulfils Kant's idea of a priori knowledge, as knowledge from pure reason without need of observation. A parameter-free model allows computational ab initio prediction.  

Here are examples of mathematical models which are parameter-free in suitable units:

1. Newton's Law of gravitation.
2. Maxwell's equations for electromagnetics.
3. Euler's equations for incompressible flow with vanishingly small viscosity.
4. Schrödinger's equations for atoms and molecules.

Newton's Law allows prediction of the motion of celestial objects. 

Maxwell's equations predicts existence of electro-magnetic waves traveling at constant velocity. 

Computational solution of Euler's equations allows prediction of drag of a body from shape alone.

RealQM computational solution of Schrödinger's equations allows prediction of spatial configurations of molecules formed by atoms. 

We see that a large part of the physical world is open to ab initio a priori investigation by pure reason in the form of computation. Not bad! Go ahead and Calculate!