CODEXCard 4 of 5 · 5 Laws of Stupidity
Cipolla fourth law of stupidity (Fourth Law - The Underestimation)
Non-stupid people consistently underestimate the damage.
Cipolla's fourth law of stupidity holds that reasonable people routinely misjudge how much harm stupid people are able to cause. They keep forgetting that getting entangled with such behaviour almost always ends up being expensive, and they keep being surprised.
The trap is the surprise itself. You deal with someone careless, you escape with a small loss, and you shrug it off as bad luck. Because nothing is updated in your mental model, you engage in the same way next time. Cipolla's practical point is that damage from pointless behaviour is hard to predict and easy to underrate, because it does not follow the logic you would use to estimate it. You cannot reason about the worst case of someone who is not reasoning.
The opposite failure is paranoia. The law does not ask you to treat every person as a threat or to expect disaster from every meeting. Most interactions go fine. The lesson is about learning after real evidence: when someone has already caused needless harm, take that seriously instead of hoping it was a one-off.
This connects to the general idea of updating your beliefs on evidence. A good forecaster adjusts after being wrong. Cipolla asks for the same habit with people whose behaviour has already cost you.
Example
A contractor once left your kitchen half-finished and blamed the supplier. A year later he quotes cheaply for the bathroom and you hire him again because the last time was only mildly painful. This time the plumbing leaks into the flat below. The first episode was the warning you did not price in.
Try it this week
Write down one person or vendor who caused needless trouble before, and decide in advance what you will do differently next time.
From 5 Laws of Stupidity (Carlo M. Cipolla · 1976).
