For lack of anything better to say, I've dredged up an old USENET post of mine from the long ago days of the 20th century.
This was in response tojames_nicoll asking why there was so much Alternate History SF around.
I was a bit proud of what I cranked out, at least by my standards:
(I've left it as is except for fixing typos and formatting. Obviously some of this stuff is dated.)
(Why is LJ text editor so sucky? If I put blank lines in there, maybe I want them there!)
Because the Goddess PsychoHistory has fallen, and she can't get up.
More precisely, Eris has tripped her, and jumped up and down on
her with spiked shoes, scattering tiny little bits to the five winds.
In the Golden Age of SF, it was often postulated, if not assumed
that psychology and sociology and suchlike would soon undergo
fundamental breakthroughs and lead to strong technologies,
just as had happened chemistry and physics.
As the Golden Age faded, and eventually the New Wave, people
began to realize that breaking through in these social sciences
might be harder than anticipated, and that even after the process
of history was understood, there might not be anything feasible to be done.
But through it all, there was the underlying idea that history
was fundamentally deterministic, that people behave they way they
do for reasons, and that at least in principle, the clockwork
universe could be totally envisioned from its initial state.
While there was wide disagreement as to how the future would
develop, it was agreed that whatever the course *was* pretty
much inevitable . The blind men argued about what the elephant
was like, but they were sure it was a mammal.
In the 1980s, some cracks began showing, as the energy crisis
abated instead of spiraling down into a Mad Max scenario. And
the Third World dominoes fail to fall as per schedule, and some
even stood back up.
Middle Eastern terrorists neglect to build atomic bombs, despite
the reasonably-priced do-it-yourself kits available at any Radio
The ecology neglects to suddenly nose-dive into oblivion.
Then in the 1990s everything went crazy.
The Soviet Union collapsed with little bloodshed. When
everybody knew that the Kremlin would definitely start WWIII
to distract the populace from their lack of decent VCRs. Or at
the very least have a civil war with nuclear weapons.
Damn-it, can't these people read the script?!
Then the US lead coalition trounces Iraq soundly, having neglected
to remember that the US wasn't allowed to win wars after Vietnam.
In the 1980s I took it as given that there were three hopeless
situations in the world where no solution was possible and massive
bloodbaths were inevitable. South Africa, Northern Ireland, and
All three places spent the 90s making me look like a fool, which
pleased me greatly .
The inevitable March of the Morons was canceled when not enough
morons showed up.
The unstoppable population bomb fizzled because ... well it did,
but I'm not sure why.
The lunar colonies with cheap fusion power failed to show up, as
did the air cars and rocket-packs.
But everybody has a computer, which churlishly refuses to become
sentient and try and take over the world.
To sum up, for the past twenty years the world has been vigorously
rubbing our noses in the fact that history is an unpredictable
So if history is one long series of crap shoots, what would
have happened if William the Bastard hadn't rolled that natural
crit back in 1066?
Dreams don't Fail. Dreams don't Succeed. Sh*t just happens.
That's my theory, anyway.
 I should tie this in with time travel stories, but I don't
have the classic ones organized in my mind. If you chart date of
publication vs. how difficult time is to change, what does the curve
1/3 right after all. Bugger.
For the original USENET post look here.