We have never been more secure.  We have never been more vulnerable. Forgive the mangling of beginning of A Tale of Two Cities, but these sentiments are true.  The complexities of society and technology have made us safer than ever before from disease, starvation, and invasion by barbaric hordes.  At the same time, any complex system depends on so very many of its individual parts – working correctly – that a single minor malfunction can begin a chain reaction that cascades into catastrophe. An example from biology should suffice.  Cutting a starfish in half does not kill it.  The creature is very simple, and both severed halves can each regenerate into a new, complete starfish.  But an elephant, a much larger and vastly more complex creature, can be killed by a single spear thrust to the heart. Human societies are like that.  Primitive groups of nomads survived for millennia despite periods of natural catastrophes, because they...(Read Full Post)