Part 1: Johannes Kepler was able to predict the observed positions of the planets by application of his third law that asserts that the square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit. Is Kepler's law an explanation for the positions of the planets?
Part 2: Is Kepler's law a causal explanation for the planets' positions?
Part 3: Nearly one hundred years after Kepler, Newton was able to derive the same law from his principle of universal gravitation. Does Newton's derivation provide a causal explanation for the original observations?
Part 4: Newton was criticized for his theory of gravity because it introduced force-at-a-distance without providing an explanation for that force. To what extent if any does Newton's use of force-at-a-distance attenuate his argument?