Goodhart’s Law is a common phenomenon everyone should be aware of.

When a measure becomes a target, it ceases to be a good measure.

“Measure” here refers to anything that can be measured, including things that you think might bring you happiness. Goodhart’s Law is often the cause of failure for self-improvement programs.

Here’s a simple illustration of how the law works.

Suppose a town elects a new mayor who campaigned on a get-tough-on-crime platform. The new mayor sets her focus on the crime rate. “Get that crime rate down,” she tells the police department. The police respond to this command in the most straightforward way: They look for reasons not to file crime reports. The fewer reports filed, the lower the measured crime rate is.

Initially, the new mayor touts her success in reducing crime. Meanwhile, criminals notice that their offenses are less likely to be tracked. They exploit this situation, leading to an increase in actual crime incidents. By the end of the mayor’s term, the public realizes that crime has, in fact, worsened. The mayor is voted out, and a new tough-on-crime mayor is elected.

This new mayor tells the police that they’re not arresting enough criminals. The police respond to this command in the most straightforward way: They look for reasons to arrest people. Arrests for all sorts of minor infractions increase, and the courts fill with people seeking to be found innocent. Convictions fall, and citizens complain of police harassment. The police spend so much time chasing petty criminals to score lots of arrests that they lose focus on serious crime. Murdur surges.

This new mayor is not re-elected, and the story goes on.

Now, apply Goodhart’s law to the search for happiness - the quest for eudaimonia.

Suppose you decide to become an Epicurean. Then, you start focusing on maximizing pleasure and minimizing pain. You start measuring these things. You have to. It’s necessary for Epicurean hedonistic calculus.

Or suppose you decide to become a Stoic. Then you start focusing on being as virtuous as possible, based on the Stoic dogma that virtue is the only good. You take up journaling every day, like Marcus Aurelius, to measure and record your efforts to pursue virtue.

In either case, you are exposing yourself to Goodhart’s Law. In your certainty that you should go chasing after the “good,” be it pleasure or virtue, you start focusing on what it is that you measure, and start paying less attention to things that you aren’t measuring.

Things can go wrong for you in a myriad of different ways. Maybe in your Stoic quest to master aversion, you swap your long, hot showers for cold ones. And, suppose that works. You do start to be better able to control your reactions to aversive physical stimuli. However, you used to have some good ideas come to you during those long, hot showers - ideas that resulted in improvements to your life. These ideas don’t come anymore now that you spend that time mastering your aversion. You become less creative. You solve fewer problems. Your life actually becomes worse over time.

And how that came about is all a mystery to you. You’ve been carefully recording everything. And at first, things did seem to improve. Now they’re worse than when you started. While you may not be able to connect the dots, maybe you’ll start to think that this Stoicism stuff isn’t so great after all. Maybe you’ll chuck it and find some other self-improvement program. There you’ll start measuring different things. The results will be good - at first. Then the cycle will repeat.

While measuring is useful for lots of things, for the things we most care about, it runs into the problem of Goodhart’s Law. I suspect that the ancient Greek philosopher Pyrrho had some idea of the existence of Goodhart’s Law when he cribbed the Buddhist Three Marks of Existence as the foundation for a new philosophy that he took back to Greece. This may explain one of the translation choices he made.

One of the Three Marks of Existence is dukkha. “Dukkha” typically gets translated into English as “suffering,” but sometimes as “unsatisfactoriness,” or “unease.” In Early Buddhism, however, “dukkha” had an additional meaning - one that seldom gets noticed much these days.

The likely origin of the word “dukkha” comes from wheelwrighting. It originally meant having a bad axle or axle-hole. You’ve likely experienced what that’s like with grocery store carts with wheel problems. Dukkha is the unpleasant disruption to the even turning of a wheel, or the smooth flow of life. Dukkha is also the instability of the wheel. This sense of instability was an important part of the understanding of dukkha in Early Buddhism, but it has since faded. Pyrrho, however, appears to have thought that this sense was the most important one.

Why this sense was the most important one likely had something to do with the philosophical problem Pyrrho wished to address. That problem was a bit different from the one the Buddha wished to address. The Buddha was interested in what made for a holy life. Pyrrho’s interest was secular: what makes for a life of eudaimonia.

If you’re interested in eudaimonia, saying that in order to achieve eudaimonia one must recognize that the nature of life entails suffering is a bit like saying eudaimonia is impossible, because life is suffering. However, saying that one must recognize that the nature of life is that it is unstable makes more sense. Hence, Pyrrho chose the Greek word astathmeta as his translation for “dukkha.”

Astathmeta has some meanings and connotations in addition to “unstable.” It also means “unbalanced” and it has the connotation of “unmeasurable” because in those days things were weighed using a balance scale. Balance scales don’t work if they are placed on unstable ground.

Here is Pyrrho’s recognition of Goodhart’s Law. If you try to apply measurements to the things that you think will bring you eudaimonia, you will fail to achieve eudaimonia.