Case of Conscience by James Blish

irrational acts. They have only one language, and have never had more than this same one—which again should have been made impossible by the geography of Lithia. They exist in complete harmony with everything, large and small, that they find in their world. In short, they're a people that couldn't exist—and yet does.
    "Mike, I'll go beyond your view to say that the Lithians are the most perfect example of how human beings ought to behave that we're ever likely to find, for the very simple reason that they behave now the way human beings once once behaved before we fell in our own Garden I'd go even farther: as an example, the Lithians are useless to us, because until the coming of the Kingdom of God no substantial number of human beings will ever be able to imitate Lithian conduct. Human beings seem to have built-in imperfections that the Lithians lack—original sin, if you like—so that after thousands of years of trying, we are farther away than ever from our original emblems of conduct, while the Lithians have never departed from theirs.
    "And don't allow yourselves to forget for an instant that these emblems of conduct are the same on both planets. That couldn't ever have happened, either—but it did.
    "I'm now going to adduce another interesting fact about Lithian civilization. It is a fact, whatever you may think of its merits as evidence. It is this: that your Lithian is a creature of logic. Unlike Earthmen of all stripes, he has no gods, no myths, no legends. He has no belief in the supernatural—or, as we're calling it in our barbarous jargon these days, the 'paranormal.' He has no traditions. He has no tabus. He has no faiths, except for an impersonal belief that he and his lot are indefinitely improvable. He is as rational as a machine. Indeed, the only way in which we can distinguish the Lithian from an organic computer is his possession and use of a moral code.
    "And that, I beg you to observe, is completely irrational. It is based upon a set of axioms, a set of propositions which were 'given' from the beginning—though your Lithian sees no need to postulate any Giver. The Lithian, for instance Chtexa, believes in the sanctity of the individual. Why? Not by reason, surely, for there is no way to reason to that proposition. It is an axiom. Or: Chtexa believes in the right of juridical defense, in the equality of all before the code. Why? It's possible to behave rationally from the proposition, but it's impossible to reason one's way to it. It's given. If you assume that the responsibility to the code varies with the individual's age, or with what family he happens to belong to, logical behavior can follow from one of these assumptions, but there again One can't arrive at the principle by reason alone.
    "One begins with belief: 'I think that all people ought to be equal before the law.' That is a statement of faith, nothing more. Yet Lithian civilization is so set up as to suggest that one can arrive at such basic axioms of Christianity, and of Western civilization on Earth as a whole, by reason alone—in the plain face of the fact that one cannot. One rationalist's axiom is another one's madness."
    "Those are axioms," Cleaver growled. "You don't arrive at them by faith, either. You don't arrive at them at all. They're self-evident, that's the definition of an axiom."
    "It was until the physicists kicked that definition to pieces," Ruiz-Sanchez said, with a certain grim relish. "There's the axiom that only one parallel can be drawn to a given line. It may be self-evident, but it's also untrue, isn't it? And it's self-evident that matter is solid. Go on, Paul, you're a physicist yourself. Kick a stone for me, and say, "Thus I refute Bishop Berkeley.'"
    "It's peculiar," Michelis said in a low voice, "that Lithian culture should be so axiom-ridden, without the Lithians being aware of it. I hadn't formulated it in quite these terms before, Paul, but I've been disturbed myself at the bottomless assumptions that