Thicker Than Water

Did the idea for the Castor books come to you fully realised or did you have one particular starting point from which it grew?

The starting point was Castor himself: the idea of a Chandler-style private eye who’s actually a private exorcist. Then I had a subsidiary idea for the mechanics of the story - for how the various undead beings could be explained and connected to each other. Throwing those two ideas against each other gave me a rough vision of how the first three novels would play out, and the big reveal we might play towards in the longer term - if there was a longer term.

Like you, Felix Castor hails from Liverpool but makes his home in London. The advantages to this ‘write what you know’ approach are obvious, but have you found any pitfalls to writing Castor’s history so much in line with your own?

Yes! In Thicker Than Water, the fourth novel, I take Castor back to Liverpool. There’s a lot about his parents there, a lot about his brother Matthew, a lot about his relationships with other kids he knew in Walton.

Without going into detail, there were whole chapters there that I wrote and then cut out because I realised after I’d written them that they were (a) confessional and (b) cathartic. They were there for me, not for the reader, and they just had to go. I also had to change some details for more mundane reasons, to avoid getting punched in the face the next time I see some of my friends and relatives.

Your take on the supernatural is almost scientific in its logic.

Do you think there is a scientific explanation for everything or do you have some belief in the supernatural?

I’m an atheist when it comes to God, but an agnostic when it comes to most supernatural phenomena. Don’t get me wrong, I come at these things from a rationalist perspective - and I’m dead set against the way the rationalist consensus is now under attack by extremists in pretty much every organised religion. But I don’t necessarily see a fixed and unwavering line between the things that science can explain and the things that it can’t.

Quantum physics, if you see it from one point of view, looks very much like superstition and mumbo jumbo. I’m a rationalist but not a materialist: I believe in spirit, in a sort of animistic essence that outlives the body, whether or not it can be seen and measured. So I don’t see any reason why the existence of ghosts, for example, offers any kind of affront to a scientific world view.