"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...Jay Forrester has demonstrated it mathematically, with his computer models of cities in which he makes clear that whatever you propose to do, based on common sense, will almost inevitably make matters worse rather than better. 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 obliged to understand, in detail, the whole system, and for very large systems you can't do this without a very large computer. Even then, the safest course seems to be to stand by and wring hands, but not to touch...Intervening is a way of causing trouble."
« Lewis Thomas, from the essay "On Meddling", _The_Medusa_and_the_Snail_, Viking Pr., New York, 1979 »