In a previous post I got into a bit of a dust up about hard SF and the Singularity, and since that post catapulted my blog to a Technorati score under 1 million, I thought I'd continue the discussion.  In the comment thread Jack William Bell expressed surprise that I still claim to write hard SF even though I don't consider science fiction to be a prediction of the future.  If I don't believe that what I write is an accurate description of future events, why bother conforming to physical laws?  If I acknowledge that I'm making all this up, why not go all out and make up the whole thing?  Fair question.

First, the inevitable description of what I mean when I say hard SF.  Greg Benford's definition is as good as any I've seen.  Hard science fiction is science fiction played with the net up.  The net being the physical laws of the universe: Newton's laws of motion, thermodynamics, relativity.  A hard SF story conforms to these laws as we understand them, whereas in another subgenre the author might create new laws to suit the story.  (Now, let me check, is the inevitability of superhuman intelligence one of those unbreakable physical laws?  Hmm, don't see it here.)

I'll address two arguments I've heard before because there's a good chance someone will have thought of them by now.  First, about physical laws as we understand them.  It's true that scientists are finding out new physical laws all the time, and erasing some of the old ones.  Take Newton's laws, for example.  Newton's theory of gravity is largely supplanted by Einstein's.  However, Newton's laws came from careful observation of planet sized objects we could see.  Those laws describe planetary motions quite well.  Even though general relativity shows us the underlying basis for Newton's laws were "wrong" the laws still hold up quite well in most situations we'd encounter.  It isn't right to say we threw out Newton's laws, we just added to them.  In fact, NASA flight controllers still use Newton's laws to guide spacecraft, even though those laws are "wrong."  They are right enough for government work, and if they're good enough for NASA they're good enough for me.  Until my story gets near a black hole, then it's out with Newton.

A second argument that I get about hard SF is that it's all about science and thus of no interest to most people.  Here's the thing: a story is about people.  The characters are the center of it all, their motivations and interactions drive the story.  The hard SF stuff is just set dressing, backdrops, props.  It makes the story interesting, but it isn't the story.

OK, so I'm a writer, I write about people, and the situations I choose to place those people in often put them in jeopardy in a cruel and unyielding universe full of physical laws that they can't break no matter how much they might want to.  Why do I do that?

1. I'm a scientist, and science interests me.  I read about science every day, I talk to other scientists, I think in the scientific method all day long.  It isn't that surprising that when I come home at night and think up a story, science is going to be a big part of whatever I come up with.  I also enjoy telling other people about science, like I did two paragraphs up.  Any chance I get to spread a little science propaganda, I take it.
2. Hard SF is what I like to read.  I read a lot of other stuff, some of it not even science fiction.  But probably half of what I read is hard SF.  I studied at the feet of Hal Clement, the dean of hard SF, and I grew up on a steady diet of Asimov, Clarke, and Harlan Ellison (who isn't a hard SF writer, but full disclosure, I have other influences.)
3. I like the challenge.  I like building a story around a rigid structure of the Universe as we understand it right now.  I like not being able to bend the light speed limit or work around the first law of thermodynamics (which says that matter/energy can not be created or destroyed).  I like to see what I can get away with and what I can't.  It's no different than writing in a rigidly defined shared-world like Star Trek or the vampire mythos.  There are some things you can do, and some things you can't, and you have to study to know which is which, and it's fun to see how far you can take things without breaking the rules.  It just so happens that this hard SF shared world is defined by scientists rather than mythology or other writers.
4. It's the way my brain works.  I have a mechanical mind.  I think in terms of objects moving through space.  When I look at the world I see matter and energy interacting, and I find it all beautiful.  When I hear about an event I want to know how it happened on the molecular level.  It's just the way my mind is, and that all spills out when I write.