In the first chapter his fascinating, to-me-almost-incomprehensible account of infinity, Everything and More, David Foster Wallace talks about levels of abstraction. In order to learn math, you have to move up through levels of abstraction, from physical objects, to numbers, to unknowns, to functions and so forth. If you are unable to manipulate the abstractions, you are unable to go on with math. And, often, even if you do well at math (as I did), you don't really understand it.

The big bucks in our economy come to those who have moved vast numbers of levels up the ladder of abstraction. The person who sells apples makes little, never mind the person who picks them. The person who creates financial instruments that hedge commodity price fluctuations makes a great deal more.

Science fiction is about the future. In the future, anyone who matters will deal with matters so many levels above concrete physical reality that there will be no clear relationship between the two. But that's not that interesting to read about, save in a tight story that is really, in some sense, about that process of abstraction, and what it means, both for the world and for the human soul. But how often can you do that?

Which is why you still see characters repairing physical things, like space drives or time machines, rather than trying desperately to fix a system of busted collateralized debt obligations. Or, even worse, arguing about how to define the problem to be fixed.

This is an interesting problem for fiction, because the people doing the abstracting are still shaved primates, with status hierarchies, anxieties, and flawed bodies that will inevitably stop working. It's that boundary between profit-and-knowledge-creating abstraction and human need that is a fertile ground for our fiction.