Like all power seekers, Pae was amazingly shortsighted. There was a trivial, abortive quality to his mind; it lacked depth, affect, imagination. It was, in fact, a primitive instrument. Yet its potentiality had been real, and though deformed had not been lost. Pae was a very clever physicist. Or, more exactly, he was very clever about physics. He had not done anything original, but his opportunism, his sense for where advantage lay, led him time after time to the most promising field. He had the flair for where to set to work, just as Shevek did, and Shevek respected it in him as in himself, for it is a singularly important attribute in a scientist. It was Pae who had given Shevek the book translated from the Terran, the symposium on the theories of Relativity, the ideas of which had come to occupy his mind more and more of late. Was it possible that after all he had come to Urras simply to meet Saio Pae, his enemy? That he had come seeking him, knowing that he might receive from his enemy what he could not receive from his brothers and friends, what no Anarresti could give him: knowledge of the foreign, of the alien: news…

He forgot Pae. He thought about the book. He could not state clearly to himself what, exactly, he had found so stimulating about it. Most of the physics in it was, after all, outdated; the methods were cumbersome, and the alien attitude sometimes quite disagreeable. The Terrans had been intellectual imperialists, jealous wall builders. Even Ainsetain, the originator of the theory, had felt compelled to give warning that his physics embraced no mode but the physical and should not be taken as implying the metaphysical, the philosophical, or the ethical. Which, of course, was superficially true; and yet he had used number, the bridge between the rational and the perceived, between psyche and matter, “Number the Indisputable,” as the ancient founders of the Noble Science had called it. To employ mathematics in this sense was to employ the mode that preceded and led to all other modes. Ainsetain had known that; with endearing caution he had admitted that he believed his physics did, indeed, describe reality.

Strangeness and familiarity: in every movement of the Terran’s thought Shevek caught this combination, was constantly intrigued. And sympathetic: for Ainsetain, too, had been after a unifying field theory. Having explained the force of gravity as a function of the geometry of spacetime, he had sought to extend the synthesis to include electromagnetic forces. He had not succeeded. Even during his lifetime, and for many decades after his death, the physicists of his own world had turned away from his effort and its failure, pursuing the magnificent incoherences of quantum theory with its high technological yields, at last concentrating on the technological mode so exclusively as to arrive at a dead end, a catastrophic failure of imagination. Yet their original intuition had been sound: at the point where they had been, progress had lain in the indeterminacy which old Ainsetain had refused to accept. And his refusal had been equally correct—in the long run. Only he had lacked the tools to provide it—the Saeba variables and the theories of infinite velocity and complex cause. His unified field existed, in Cetian physics, but it existed on terms which he might not have been willing to accept; for the velocity of light as a limiting factor had been essential to his great theories. Both his Theories of Relativity were as beautiful, as valid, and as useful as ever after these centuries, and yet both depended upon a hypothesis that could not be proved true and that could be and had been proved, in certain circumstances, false.