It’s hard to deny that magic is the default mode of human storytelling. All the old myths and poems contain transcendent magical powers and transitions. Medieval romances and epics are full of fantastical and miraculous things. It wasn’t until the 18th and 19th centuries in which stories arose in which nothing magical happened, and verisimilitude became the watchword. We sometimes call it realism. I have nothing against realist novels, as it happens… I just think we need to acknowledge that they are the aberration in the larger context of humanity’s appetite for stories. For the moment however, this rejection of the power of miracles extends even to our stories about the miraculous. One feature that Rowling’s and Pratchetts’ series share with nearly all narratives and stories predicated upon magic is that magic has rules. This is because magical thinking has rules. Psychological rules, that is. Magical thinking is that near-ubiquitous human state of mind at work in ritual, prayer, and religion, as well as obsessive compulsive behavior. The belief that there is a causal relationship between human actions and beliefs, and cosmic eventuality. I wonder what it would be like to write a fantasy novel in which the magic has no rules at all. That would be bracing, and might bring out this buried truth: millions who think they love fantasy because of the magic actually love it because of the rules.
Adam Roberts, forward to Monday Starts on Saturday (2017)