I then discovered to my great shame the following. I had spent my life thinking about randomness; I had written three books on dealing with randomness (one technical); I was prancing about as the expert in the subject of randomness from mathematics to psychology. And I had missed something central: living organisms (whether the human body or the economy) need variability and randomness. What’s more, they need the Extremistan type of variability, certain extreme stressors. Otherwise they become fragile.
