In a seventeenth century world the Newtonian model did mostly very well to describe how gravity works in the universe and did well with most empirical evidence of that time. Of course now we know that gravity is not that Newtonian but described more correctly by General Relativity. My question is does there exist an ad hoc hypothesis that we could add to the Newtonian model to arrive at the Einsteinian model and more generally can we always find an ad hoc hypothesis to result in a more sound generalization ? Because if we can I think this will violate the heuristic of parsimony that the simpler theory is more likely to be correct since this likelihood decreases as we have more chances of finding an ad hoc hypothesis that will result in a more general theory. Does this mean a particular over-fitted extrapolation (which would contain that particular ad hoc hypothesis) out of many such over-fitted model will stand a chance of predicting with higher accuracy thus disproving the bias-variance trade-off ?