"for every conceivable change". That is not what he is arguing at all. He is showing that there are very many highly plausible changes that are problematic wit

"for every conceivable change". That is not what he is arguing at all. He is showing that there are very many highly plausible changes that are problematic with natural keys. And he totally correct about that. Frankly, the fact that a post arguing for natural keys makes it the top of an HN comment thread is extremely weird. The original article is correct that natural keys are bad.