Everywhere you look there's evidence.
So many of the systems we've built work nice, for now, but when one component fails, how will all the others respond. How is Japan dealing with the Fukishima meltdown? This is a country that depends on nuclear heavily -- they have no oil of their own, and their economy isn't so strong, so what do they do now that they've had a taste of what nuclear-mageddon looks like.
Great piece in today's NYT about data centers. Nice illusion there, but it's not sustainable. Yes that's where our bank balances and medical records are stored.
What if something happened to corn? Or if we run out of antibiotics? Believe it or not the questions are related. Something that seems as as reliable as corn might not always be so.
And philosophically and intellectually our minds can't grasp the complexity of the world we live in. That's why politicians who talk nonsense are so convincing. What they're really saying is Relax don't worry, things aren't really as complex as they seem. I can reduce it down to grunts and snorts.
We have far more people doing far more with technology than our resources can support, than our intellect can comprehend. It's exhausting.