Not OP, but "natural fallacy" might mean the idea that what's natural is good, and what's "chemical" is bad. It's prevalent, and wrong, I think.
For me, that's quite distinct from the naturalistic fallacy, which is really related to the is-ought distinction (often attributed to Hume). The fallacy consists of going from a descriptive statement (this is how things are) to a normative statement (thus, this is how things should be). A (fallacious) example would be that strong animals devour weaker animals, thus it's good and proper also in our society that the strong exploit the weak. For me, that's an illicit move from "is" to "ought", and quite distinct from the "untreated water is natural and thus must be healthy", "vaccines are chemical and unnatural and thus must be bad" fallacy.
However, from the Wikipedia page it seems that some people also use "naturalistic fallacy" in the former sense ("appeal to nature").
(Note that Sam Harris and others are arguing (convincingly, in my view) that ultimately, our "oughts" must be informed and even follow from "is", from descriptive statements, rejecting the whole strict is/ought distinction.)
For me, that's quite distinct from the naturalistic fallacy, which is really related to the is-ought distinction (often attributed to Hume). The fallacy consists of going from a descriptive statement (this is how things are) to a normative statement (thus, this is how things should be). A (fallacious) example would be that strong animals devour weaker animals, thus it's good and proper also in our society that the strong exploit the weak. For me, that's an illicit move from "is" to "ought", and quite distinct from the "untreated water is natural and thus must be healthy", "vaccines are chemical and unnatural and thus must be bad" fallacy.
However, from the Wikipedia page it seems that some people also use "naturalistic fallacy" in the former sense ("appeal to nature").
(Note that Sam Harris and others are arguing (convincingly, in my view) that ultimately, our "oughts" must be informed and even follow from "is", from descriptive statements, rejecting the whole strict is/ought distinction.)