Nature is the set of existent things
If supernatural is the set of things that are not natural or non-existent, then what you seem to be asking is ....
"How can I tell if something non-existent has helped me ?"
If supernatural is the set of things that are not natural or non-existent, then what you seem to be asking is ....
"How can I tell if something non-existent has helped me ?"
Insanity - Doing the same thing over and over again, expecting a different result