Something a little bit different today. I’ll tie it in to progress, I promise.

I keep noticing a particular epistemic pitfall (not exactly a “fallacy”), and a corresponding epistemic virtue that avoids it. I want to call this out and give it a name.

The virtue is: identifying the correct scope for a phenomenon you are trying to explain, and checking that the scope of any proposed cause matches the scope of the effect.

Let me illustrate this virtue with some examples of the pitfall that it avoids.

Geography

A common mistake among Americans is to take a statistical trend in the US, such as the decline in violent crime in the 1990s, and then hypothesize a US-specific cause, without checking to see whether other countries show the same trend. (The crime drop was actually seen in many countries. This is a reason, in my opinion, to be skeptical of US-specific factors, such as Roe v. Wade, as a cause.)

Time

Another common mistake is to look only at a short span of time and to miss the longer-term context. To continue the previous example, if you are theorizing about the 1990s crime drop, you should probably know that it was the reversal of an increase in violent crime that started in the 1960s. Further, you should know that the very long-term trend in violent crime is a gradual decrease, with the late 20th century being a temporary reversal. Any theory should fit these facts.

A classic mistake on this axis is attempting to explain a recent phenomenon by a very longstanding cause (or vice versa). For instance, why is pink associated with girls and blue with boys? If your answer has something to do with the timeless, fundamental nature of masculinity or femininity—whoops! It turns out that less than a century ago, the association was often reversed (one article from 1918 wrote that pink was “more decided and stronger” whereas blue was “delicate and dainty”). This points to a something more contingent, a mere cultural convention.

*Left:* *Young Boy with Whip, c. 1840; right:* *Portrait of a Girl in Blue, 1641. Credit: Wikimedia*

The reverse mistake is blaming a longstanding phenomenon on a recent cause, something like trying to blame “kids these days” on the latest technology: radio in the 1920s, TV in the ’40s, video games in the ’80s, social media today. Vannevar Bush was more perceptive, writing in his memoirs simply: “Youth is in rebellion. That is the nature of youth.” (Showing ...

Epistemology