Why the hell not? Calling something supernatural does not mean you are verifying it, putting a stamp of authenticy from the Hogwarts academy.
If you conclude that it was supernatural then that is exactly what you are doing. You have found the cause, you have found the how and it is supernatural, in that it is unable to be explained by science and it violates the laws of nature.
How could you possible know this?
If what you mean instead is that this event
appears to violate the laws of nature but you don't really know how it happened and need to investigate further, then what you should be saying is that the answer/cause is unknown.
It is a word. We use words to convey ideas. If something meets the definition of being supernatural then by golly why not call it that.
Sure, except that I don't think we could demonstrate that anything meets the definition of supernatural, except in instances where calling the cause unknown would not be more appropriate.
quote:
supernatural adjective \ˌs-pər-ˈna-chə-rəl, -ˈnach-rəl\
: unable to be explained by science or the laws of nature : of, relating to, or seeming to come from magic, a god, etc.
Full Definition of SUPERNATURAL
1
: of or relating to an order of existence beyond the visible observable universe; especially : of or relating to God or a god, demigod, spirit, or devil
2
a : departing from what is usual or normal especially so as to appear to transcend the laws of nature
b : attributed to an invisible agent (as a ghost or spirit)
The word has baggage and I suspect that most people would assume the primary definition above, or at least the first definition under "Full Definition".
If you are instead using something closer to 2(a) then, as explained above, I think unknown would serve better and avoid the implication that science will never be able to explain it.