A really good interview with the inhumanly productive Adrian Tchaikovsky about his writing practice, which (of course) contains some good thoughts on worldbuilding:

Tchaikovsky is unusually good at explaining his process without devolving to mysticism; I think there’s some mysticism there, and he does in fact talk about coming to rely on the “subconscious” for a lot of the imaginative back-filling, but he has a very clear sense of where he’s handing over to that side of the operation, which is interesting. I myself do a similar handover, as I expect almost every author does, but I’m nowhere near so clear on where the demarcation lies.

(Whether the line actually lies where the rational part of the operation thinks it lies is another question entirely, of course.)

He talks a lot about how, for him at least, story emerges almost entirely from the worldbuilding work—an approach that some writers feel to be something close to blasphemous. In truth I’m not so sure that these two camps aren’t really disagreeing over terms of art, rather than the process itself: for Tchaikovsky, world implies context and society which therefore implies character, and it is from character that plot emerges, almost spontaneously (for him at least). If you set aside the imagining-a-different-world part at the start, the character-first dynamic sounds a lot like the process that “literary fiction” tends to valorise.

I was particularly interested in Tchaikovsky’s analogy of the “left wall” in worldbuilding: this is the (ideally) coherent and consistent systemicity that keeps the story from veering into wish-fulfilment and/or Idiot Plot, and can be based either on “science” for sf or a consequential system of other stuff for fantasy. In other words, with sf you have to research whatever is backstopping the story, whereas with fantasy you can in theory build it from scratch (even if, in practice, almost no one actually does so).

Quite why he thinks of it as a wall (rather than, for instance, a floor) is left unexplored… but one rather gets the impression that, if you asked him, he’d have a clear and well-thought-out answer ready to go.