Viv... You are making an assumption that they thought it was magical.
They had the intelligence to know it was a physical force be it gentle or highly agitated, they knew it entered the body physically through the nostrils or mouth they knew it madethe chest rise and fall, they knew without it there was no more life they . They also knew its force could bring down trees.
Don't you think they would see it as a physical force. We insult their intelligence not to think so.
If some saw it as supernatural then they were just as deluded as some people today.