I recently saw a bag labeled - and I quote - “Organic Charcoal”. What does this mean? That there were no additives in the wood before they charred it? That the wood wasn’t genetically modified? Technically, ‘organic’ chemistry is the chemistry of carbon; and charcoal is little but carbon; so all charcoal is organic.
And by the way, what does ‘natural’ mean? As near as I can tell, everything in the universe, including ourselves, obey the laws of nature, and in that sense is natural. For something to be unnatural, it would have to be from Cthulhu or something. And as for artificial; anthills, bee hives, termite colonies and beaver dams are the result of artifice. Are they natural?
Your argument is essentially the same as Hume’s argument against miracles (which see). If our only knowledge of what is ‘in the course of nature’ comes from what actually does happen, how can it make sense to say that anything that actually happens is contrary to the course of nature. This not only undermines the notion of a miracle, it puts paid to any notion of any actual behavior’s being “unnatural.”