"When Newton demonstrated that the force which acts on each of the heavenly bodies depends on its relative position with respect to the other bodies, the new theory met with violent opposition by the advanced philosophers... who described the doctrine of gravitation as a return to the exploded method of explaining everything by occult causes, attractive virtues, and the like. Newton... answered that he made no pretence of explaining the mechanism... To determine the mode in which their mutual action depends on their relative positions was a great step in science, and this Newton asserted he had made."