> I was replying that "what they're intended for" has no causal power (and thus shouldn't affect how controversial it is) -- the chemical mechanisms that play

> I was replying that "what they're intended for" has no causal power (and thus shouldn't affect how controversial it is) -- the chemical mechanisms that play out don't look at policymaker intent. I don't know what you find so objectionable about that point. It's not objectionable so much as it's backwards: policymakers can't control what a chemical or element does, but they can make policy decisions based on specific known properties of a chemical or element. It's not like we just YOLO'd fluoride into the water in the 1960s and have cargo-culted that practice into the present: the science on safe fluoride levels was sound back then, and continues to be substantiated by current research. I think you read too much about "intent" into the original comment. The comment's whole point was that fluoride's value for dental health is incontrovertible, and was incontrovertible ~60 years ago. That's how it fits into the above. If there was any evidence either now or 60 years ago that municipal fluoridation at CDC levels did anything except improve the public's dental hygiene, then there would be a reasonable call for controversy here. But no such evidence exists.