Appeal to nature
Etymology
The fallacy formalizes a folk assumption that the natural order carries a stamp of approval. It is a cousin of the naturalistic fallacy discussed by G.E. Moore, though the two are not identical — Moore’s concerns defining "good" in natural terms at all. Here the error is simply equating "natural" with "good."
noun phrase · /uh-PEEL too NAY-chur/
Arguing that something is good or right because it is natural, or bad because it is unnatural.
What it names
Breaks the reflex that treats "natural" as a synonym for "safe" or "moral," when many natural things are neither.
Example
"It’s a natural remedy, so it can’t hurt you" is an appeal to nature — hemlock is natural too.
Related idea
It often pairs with an appeal to tradition, which swaps "natural" for "how it’s always been done."