As large as worlds. As old as Time. As patient as a brick.

A lot hinges on the fact that, in most circumstances, people are not allowed to hit you with a mallet. They put up all kinds of visible and invisible signs that say, 'Do not do this' in the hope that it'll work, but if it doesn't, then they shrug, because there is, really, no real mallet at all.

Ultimately, there is the freedom to take the consequences.

I used to think that I was stupid, and then I met philosophers.

Dwarfs were not a naturally religious species, but in a world where pit props could crack without warning and pockets of fire damp could suddenly explode they'd seen the need for gods as the sort of supernatural equivalent of a hard hat. Besides, when you hit your thumb with an eight-pound hammer it's nice to be able to blaspheme. It takes a very special and strong-minded kind of atheist to jump up and down with their hand clasped under their other armpit and shout, "Oh, random-fluctuations-in-the-space-time-continuum!" or "Aaargh, primitive-and-outmoded-concept on a crutch!

Once you've ruled out the impossible then whatever is left, however improbable, must be the truth. The problem lay in working out what was impossible, of course. That was the trick, all right. There was also the curious incident of the orangutan in the night-time.

This is space. It's sometimes called the final frontier. (Except that of course you can't have a final frontier, because there'd be nothing for it to be a frontier to, but as frontiers go, it's pretty penultimate . . .)