Lewis Thomas on interventions in complex systems

Sterman quotes Lewis Thomas in Lives of a Cell, 1974 (p90):

When you are confronted by any complex social system, such as an urban center or a hamster, with things about it that you're dissatisfied with and anxious to fix, you cannot just step in and set about fixing with much hope of helping. This realization is one of the sore discouragements of our century. You cannot meddle with one part of a complex system from the outside without the almost certain risk of setting off disastrous events that you hadn't counted on in other, remote parts. If you want to fix something you are first obligated to understand... the whole system.. Intervening is a way of causing trouble.