In Rivers of London I decided that while I understood the way magic worked, I am the creator after all, the practitioners of magic both Newtonian and natural, had to work within an incomplete and, in some cases, erroneous theoretical base.
In the first novella 'The Roaring Trumpet' our hero, transported to a world of Nordic myth, confidently steps forward to slay a dragon with his pistol only to find that it doesn't work. There's nothing mechanically wrong with his gun it's just that in this particular universe the chemical reactions that facilitate firearms don't work.
When you're 11 years old this is heady stuff but more importantly it teaches you to think critically about how magic will fit into your world.
But the truth is that you'd be hard pressed to find a more concentrated form of ideas anywhere else. For writers of a certain bent they are the crack cocaine of research materials. You know it might be bad for you but the hit is so...so... fast.
It was Ars Magica's use of Latin words to describe the building blocks of Hermetic magic was a direct inspiration for the formae Nightingale teaches Peter in Rivers of London. This set me thinking about what exactly is it you are doing in your brain when you speak a magic spell and the idea that the words were abstract labels, like musical notes, whose purpose was to regulate the way you formed the shapes in your mind.
The founding of the Folly and the codification of magic by Isaac Newton owes itself to a throwaway remark in this book. In it they discuss Newton's interest in religious philosophy and alchemy, which the writers make clear is a waste of Newton's time, one of them, in the footnote, does point out that if anyone in the history of science was going to discover the principles of magic it was Isaac Newton.
A light-bulb went off in my head and voila. The moral is be careful what you say in your footnotes lest some jobbing writer rebuild his entire career on the basis for your throwaway remark.
Madouc gave a rueful grimace. ‘I had rather be a magician, and see through walls. Is it difficult to learn?’
‘Quite difficult, but much depends upon the student. I have tried to teach Dhrun a sleight or two, but with only fair success.’
‘My mind is not flexible,’ said Dhrun. ‘I cannot think so many thoughts at once.’
'That is the way of it, more often than not, and luckily so,’ said Shimrod. ‘Otherwise, everyone would be a magician and the world would be an extraordinary place.’
Madouc considered. ‘Sometimes I think as many as seventeen thoughts all together.’
(1) They weren't all giants. The best that could be said of some of them was that they were dwarves with step ladders but they tried hard and that's the main thing.
(3) In fiction it is entirely sufficient for an author to give an impression that they know what what they're doing regardless of of whether they do or not - the exact opposite of Engineering.
(4) Definitely not the one who wrote the Narnia books though.
(5) I can't believe his name was preprogrammed into my factory standard spell checker.
(6) However beautiful it looks.