ABSTRACT
The theories to which experiments relate must always be of a more restricted range. There must be a fit between what the theory predicates and what the experiments determine, if either experimentation or theorization is to be of maximum usefulness. Clearly, what began as a factual study of the attractive and repulsive properties of matter has ended as a very different metaphysic; experimentation, seemingly a guarantee of realism and defence against wild-ranging speculation, has proved to be nothing of the kind. The Cartesian mechanical philosophy was of a similar kind-it could be illustrated by suitable experiments, but not confirmed, since its foundations were metaphysical assertions and invisible entities. With the empiricist reaction against Cartesian Science, which had seemed for a moment almost to sum up the whole revolt against tradition, and especially with the discoveries of Isaac Newton, came the test of the ability of the heirs of Copernicus and Galileo to resolve their own internal contradictions.
