The Understanding of Relativity

Abstract

MAY I have space for a last letter about the difficulties of the ordinary man with respect to relativity and kindred puzzles? Of course there is such a thing as relativity. We take it into account in daily life. But I cannot believe that modern mathematicians have overthrown fundamental axioms of thought. Such dictionaries as I have consulted define parallel lines as those which keep equidistant from each other. But a spiral wound around a straight line might keep equidistant, and yet not be parallel. Presumably parallel lines are those which keep equidistant on the same plane. If that be true, lines of longitude are not parallel for even an inch. But if lines were drawn from points at a given distance on opposite sides of one pole to points in similar relation to the other pole, they would be parallel—like lines of latitude drawn equidistant from the equator. To define parallel lines as those which meet at infinity is merely to confuse the learner by giving a contradictory meaning to an old word. It may be that lines which seem parallel in perceptual space are found to be convergent, when more than three dimensions are brought into consideration; but that proves not that a fundamental axiom of thought (that things cannot both be, and not be, at the same time) is wrong, but only that our senses deceive us.