It does exist though. Our brains are information processing mechanisms which have figured out some of the laws of the universe - and they continue to question it. They do exist and reality does 'exist.' I suppose you're questioning the validity of nature> If so - then yes, I would say it doesn't really 'exist.' Mathematical fields are really what exists...but hey, who's here to argue certainties! So what by your definition - or whom meets the criteria of 'existing' then?