I suggested in an earlier post that foresight is not so much about prediction as it's about designing against surprise. Key to this is the exploration of multiple futures, which is why scenario-based foresight is so commonly practiced. Scenarios are rarely developed in isolation, but are usually created in decks(generally of four, when one uses the common 2X2 matrix method of generating them). These are then intended as snapshots taken in different points of a complex space of possibilities.
The opposite of scenarios is the default future, which is what everybody assumes is going to happen. If life is what happens to you while you're making other plans, the real future is what happens to you after you've planned for the default future. A classic example of what you get when you plan for the default future is the Maginot Line.
In a 1998 article in the journal Futures, "Futures Beyond Dystopia," Richard Slaughter critiques science fiction's default futures. He accuses SF of oscillating between naive techno-optimism and equally naive apocalypticism. Late 20th century SF lacks the necessary spectrum of intermediate scenarios, according to Slaughter, which may explain its decreasing hold on the public imagination. What we are left with is two default futures, and no societal capacity to plan for a third. This is an idea worth serious contemplation by those of us who write the stuff.
Sometimes, too, our scenarios grow so elaborate that they become more than scenarios--they're complete paradigms. They become default modes of thinking, and come with associated cultures, champions and institutions. At this point, presenting alternatives becomes increasingly difficult; one must present, not just new scenarios, but an entirely new paradigm to complement the reigning one.
May people, particularly in the foresight community, believe that a shift from scenario to paradigm is what's happened to the idea of the Technological Singularity. It's become the new default future--no longer the shocking, thought-provoking alternative to an orthodoxy, but the very orthodoxy itself. Against this, it's no longer sufficient to simply present different scenarios. We need an alternative paradigm (or two, or six).
I've been working on some.