Worrying about whether "a person without supernatural abilities can accomplish it" is to me, trying to make a fantasy game fixed on the real world, instead of the fantasy genre.
Fafhrd could do this. Inigo Montoya could do this. Zorro could do this (and isn't even a fantasy hero!). Galavant could do this. Locke Lamora could do this. None of these characgters "use magic" in any overt sense. But, they live in worlds that are larger than life. It is genre appropriate for them to be able to do this.
The measure of magic is not the real world, but the genre you are aiming for. IMHO.