My thesis, and what I am really interested in hearing your views about, is if the complexity of our global culture and its dependence on many individual "choke points" or bottlenecks and it's incredible speed of change, makes it more or less vulnerable to suddenly cramping up.

I totally agree. I think the problem is less serious than it used to be--communications for example are a lot less centralized than they used to be, but it's still a major issue. How many people could stand having their water shut off for a week? If I were president, the first thing I'd do is resurrect a robust civil defense system. The Mormons have it right as far as emergency prep is concerned.

It took Rome 400 years to fall apart, and vestiges of its influence remain to this day, but what would a targeted hit on our civilization do to us? I can think of some non-political examples: a nearby supernova EMP frying every integrated circuit on the planet, or a virulent and devastating disease that incapacitates 80% of the world's population for a year or so (it doesn't even need to be fatal). Or how about a new and incurable plant virus that attacks only grasses (like wheat and rice).

I don't see those as good examples of a "choke point" problem. They're pretty broad hits. Slapping the planet with an asteroid is not going to have a lot of "preparation potential" either. A nuclear EMP pulse is a much better example, and something I wish more people were working on.

Burke made a valid point (and I too have seen him lecture in person--a lecture entitled "Do Lemons Whistle?").

But this has nothing to do with my main point in the post, which was about a segment of our culture that seems to be highly pessimistic about the high-tech, prosperous future that used to be more commonly believed in. I have looked at the makeup of many of the pessimists (remember, I'm looking only at the non-religious ones here. The others are a whole thread to themselves) and drawn some psychological conclusions.

When a person is a failure, and everybody is now and then, they can respond by redoubling their efforts, or in way too many cases, by hating those who succeed.