Apologies to all of those who thought and hoped this thread was dead.
Let's start out with what we all agree about: evolution has caused
increased complexity. There are undoubtably some living organisms alive
today, such as the honey bee, which are quantitatively more complex (yes,
thanks to the modern miracles of computer science, mathematics, and physics,
you can determine that your hamster is 8746.724 times more complex than
your television set) than our single celled forefathers. We all know
that evolution is what causes new species to originate, so it is safe to
say that evolution has caused complexity.
Another thing which we know that is that evolution doesn't always
cause complexity to increase. There are numerous examples of creatures
adapting to their environments by stripping down unneeded features
and getting back down to basics. So it is clear that evolution doesn't
always cause increased complexity in the short term.
So we are left with two points of contention:
1) Does evolution cause complexity to increase in the long run?
2) Is increased complexity progress?
Science fiction writers, along with SETI astronomers, are fond of
assuming #1. They reason, "Hey, just give us an earth-like planet,
wait a while for life to appear by sheer chance, then let evolution
take over. In a billion years or so, it will have evolved us
a complex flora and fauna, along with hopefully some intelligent
My basic counter-example to #1 is the Pre-Cambrian era. For over a
billion years after life originated on this planet, it stayed in
a pretty primitive state. Only a couple of multi-celled organisms,
and almost no noticeable change during the entire era. For all we
know, life could have stayed that way forever (the reasons for the
so-called Cambrian explosion are still poorly understood).
Billions of years of evolution, no increase in complexity. I think
it's safe to say that we really don't know under what circumstances
evolution causes complexity to increase. It's happened in the
"modern era" (from the Cambrian era to today), but we don't know if
it will stop tomorrow or if it would happen under some different
#2 is obviously a more philosophical question, which could be
debated endlessly (that is not an invitation!) Any reasonable
standard of progress is going to include some amount of increased
complexity, though I suppose that someone might argue that
we should all be trying to progress to that most perfect state
of total nothingness.
My own personal favorite example of the dangers of equating
complexity with progress is the Department of Defense...