In the case of the ray of light, which is sent backwards and forwards by means of a contrivance of mirrors, this fact should be clearly demonstrated by means of the interference-fringes, which are able to show much smaller effects than the experiment demands. The experimental oracle was to speak, but it remained silent. This portentous silence signified: no interference-effect, no action of the ether-current, no influence due to translation--nothing! This "nothing" compelled a decision of a very startling kind, for the result of this experiment was in direct contradiction to another famous experiment. Fizeau had proved that the ether is practically rigid and remains fixed in interstellar space. A decision had to be taken in favour of Fizeau or Michelson and Morley. Yet this was impossible, for both had operated with unsurpassable accuracy. It was impossible to reconcile both views as they were diametrically opposed. This contradiction remains, even if we assume a different hypothesis, not involving the ether, for Fizeau's experiment. A solution was impossible without undertaking revolutionary changes in the whole of physical thought. This radical change was effected by Einstein; and this mysterious contradiction disappeared in the resulting revolution of thought. Einstein supplanted the absolute time-conception by a new relative conception, and thus the perplexing problem disappeared. Two great principles arose as regulative factors in thought, and wherever these were applied, they achieved wonders: one was the new conception of time that deprived the earth of her unique position as the sovereign of time by the introduction of the principle that the rate at which time elapses is different in media moving at different speeds; the other is the principle of the constancy of the velocity of light. One feels a temptation to apply a mythical allegory: just as the world, according to the Biblical story, originated from nothing, so there arose from the "nothing" of the Michelson-Morley experiment a new world, a world of knowledge, a cosmos of thought, in which perfect harmony reigns. Its truth was contained in itself before the experimental proof was furnished. And this realization of truth has become a fact in the _experimentum crucis_ for which the sun and stars formed the material. This will be discussed in another part of the book. "The really important factor is ultimately intuition," Einstein had said to me. It made me think of Huyghens' remark about the genius who would have been able to create the telescope without the help of chance. Was not this intellect, imagined by Huyghens, sitting opposite me at that moment? An inner voice answered in the affirmative, for Einstein's thought-complex seemed to me at that moment a kind of telescope for the human mind, a telescope that had arisen out of pure intuition, and whose range stretched to the limits of the universe. CHAPTER VI OF DIFFERENT WORLDS