Legends don't have to make sense. They just have to be beautiful. Or at least interesting.

The world rides through space on the back of a turtle. This is one of the great ancient world myths, found wherever men and turtles were gathered together; the four elephants were an Indo-European sophistication. The idea has been lying in the lumber rooms of legend for centuries. All I had to do was grab it and run away before the alarms went off.

There are no maps. You can't map a sense of humour. Anyway, what is a fantasy map but a space beyond which There Be Dragons? On the Discworld we know There Be Dragons Everywhere. They might not all have scales and forked tongues, but they Be Here all right, grinning and jostling and trying to sell you souvenirs.

It cannot be said often enough that science fiction as a genre is incredibly educational - and I'm speaking the written science fiction, not 'Star Trek.' Science fiction writers tend to fill their books if they're clever with little bits of interesting stuff and real stuff.

You can't remember the plot of the Dr Who movie because it didn't have one, just a lot of plot holes strung together. It did have a lot of flashing lights, though.

I read the 'Old Testament' all the way through when I was about 13 and was horrified. A few months afterwards I read 'The Origin Of Species', hallucinating very mildly because I was in bed with flu at the time. Despite that, or because of that, it all made perfect sense.

When you read, I'm sure you don't realize that your eyes are going backwards and forwards and to this place and that place. Mine don't do that.