Deep in this post Arctic Sea Ice Volume: PIOMAS, Prediction, and the Perils of Extrapolation at RealClimate we see
Model calibration is of course necessary. We need to determine parameters that are not well known, deal with inadequately modeled physics, and address significant biases in the forcing fields.
I find this characterization to be somewhat in contrast to this characterization 
The models encapsulate our understanding of the basic science of the climate system, including for example, Newton’s laws of motion, the laws of thermodynamics and the quantum theory of radiation.
For more info on Newton’s Laws relative to fluid motions, check this out. Sir Isaac dealt almost exclusively with point mass situations and actions outside, on the boundaries of, the materials of interest. He was successful in analyses of the interactions between two point masses, and failed for three. Decades of additional work were required to bring to fruition concepts relating to actions, and consequent deformations, within the materials of interest. Some of those who contributed to this work included mainly Euler and the Bernoulli boys, and additionally Lagrange, D’Alembert, Leibniz. The Navier-Stokes equations, generally accepted to be a good description of fluids having a linear relationship between rate of strain and the associated stresses, were not formulated until the nineteenth century, almost 150 years following Newton’s Laws.
Hydrostatics, by way of Archimedes, pre-dates Newton’s Laws by several centuries: almost 20. The first edition of his Principia was published in 1687: Archimedes lived until c. 212 BCE. Stevin, somewhat later in the early seventeenth century, also made contributions that pre-date Sir Isaac.