_The Newtonian_: You are therefore compelled to admit that far away from all matter, far from all heavenly bodies, there can be what you call a gravitational field, that it varies according to the velocity of the observer, and that it can be very intense in spite of the distance of the heavenly bodies, and even, at times, increase with that distance. These are strange and absurd hypotheses. _The Relativist_: They are strange, but I defy you to prove that they are absurd. They are less absurd than to localise and set in motion a point that is isolated and independent of any material mass. _The Newtonian_: For my part, I can easily imagine a single material point in the universe having a certain position and a certain velocity in it. _The Relativist_: For my part, on the contrary, if such a material point existed, it would be absurd and impossible to speak of its position and its motion. It would have neither position nor motion nor rest. Such things can exist only with reference to other material points. _The Newtonian_: That is not my opinion. _The Impartial Spectator_: In order to know which of you is right we should need to try an experiment on a material point that is withdrawn from the influence of the rest of the universe. Can you try this experiment? _The Newtonian and the Relativist_ (together): No, unhappily. _The Metaphysician_ (coming up like the third thief in the fable): Then, gentlemen, I advise you to return to your telescopes, your laboratories, and your tables of logarithms. The rest is my affair. _The Newtonian and the Relativist_ (together): In that case we are quite sure we shall never learn anything further about it than we know or believe now. * * * * * Meantime, it is impossible to exaggerate the importance of the new light thrown on the question of Relativity by the intervention of M. Paul Painlevé at the Academy of Sciences. It will have a lasting and prodigious echo. Will Einstein’s fine synthesis be defeated? Shall we see it sink in the controversies, doubts, and obscurities of which we have given a short account? I think not. When Christopher Columbus discovered America, it was all very well to tell him that his premises were wrong, and that if he had not believed that he was sailing for the Indies he would never have reached a new continent. He might have replied, after the style of Galileo: “I discovered it, for all that.” The method that gives good results is always a good method.