But this continuum is itself only a flabby form. It has no rigidity. It adapts itself docilely to everything. There is nothing fixed, because there is no definite point of reference by means of which we could distribute phenomena; because on the shores of this great ocean in which things float there are none left of those solid rings to which mariners once fastened their vessels.
Up to this point the theory of Relativity well deserves its name. But now, in spite of it and its very name, there rises something which seems to have an independent and determined existence in the external world, an objectivity, an absolute reality. This is the “Interval” of events, which remains constant and invariable through all the fluctuations of things, however infinitely varied may be the points of view and standards of reference.
From this datum, which, speaking philosophically, strangely shares the intrinsic qualities with which the older absolute time and absolute space were so much reproached, the whole constructive part of Relativity, the part which leads to the splendid verifications we described, is derived.
Thus the theory of Relativity seems to deny its origin, even its very name, in all that makes it a useful monument of science, a constructive tool, an instrument of discovery. It is a theory of a new absolute: the Interval represented by the geodetics of the quadri-dimensional universe. It is a new absolute theory. So true is it that even in science you can build nothing on pure negation. For creation you need affirmation.
The theory of Relativity has won brilliant victories, crowned by the decisive sanction of facts. We have given some astonishing instances of these in our earlier chapters. But to say that the theory is true because it has predicted phenomena that were afterwards verified would be to judge it from too narrowly Pragmatist a standpoint. It would also—there is real danger in this—be to close against the mind other paths where there are still flowers to cull. We will not do that.
It is therefore important, in spite of its successes—nay, on account of them—to turn the light of criticism upon the foundations of the new doctrine. Even Cæsar, as he mounted the Capitol, had to listen to the jokes of the soldiers round his chariot and lower his pride. The theory of Relativity also, as it advances in all its magnificence along the Triumphal Way, must learn that it has its limits, perhaps its weaknesses.
But before we go further into it, before we turn the raw light upon it, let us make one observation.
Whatever be the obscurities of physical theories, whatever be the eternal and fated imperfection of science, one thing may be positively laid down here: scientific truths are the best established, the most certain, the least doubtful of all the truths we can know in regard to the external world. If science cannot reveal to us the nature of things in its entirety, there is nothing else that can do it as well. The truths of sentiment, of faith, of intuition, have nothing to do with those of science as long as they remain strictly truths of the interior world. They are on another plane. But the moment they claim to be measures of the external world—which would be their only cause of weakness—they subject themselves to the material reality, to the scientific investigation of the truth.
It is therefore nonsense to speak of a “bankruptcy of science” as contrasted with the certainty which other disciplines may give us respecting the external world. The bankruptcy of one would make all the others bankrupt. When it is not a question of the intimate oasis in which the serene realities of sentiment flourish, but of the arid and imperfectly explored desert of the material world, the scientific facts are the basis of all constructions. Destroy those and you destroy everything. If you ram the ground floor of a house and bring it down, you bring down also the upper stories.