Erik Angner Profile picture
Professor of Practical Philosophy @Stockholm_Uni. Author of How Economics Can Save the World 🛟 https://t.co/Bmb2kYpzpy Opinions &c. my own. Agent: JP Marshall

Sep 11, 2020, 15 tweets

In re Hanno Sauer's declaration of victory in the "reason wars": A thread. /1

Let me preface this by saying I think "war" is a terrible analogy for scholarly discourse: (a) it trivializes the real thing, (b) it suggests science is a zero-sum game, (c) it triggers norms suggesting that "all is fair," and (d) it encourages people to choose teams. /2

Anyway, let's ignore the clickbaity headline and the hard-charging introduction and go straight to the conclusion. Here's what Sauer thinks the evidence shows. /3

Sauer defends something called "rationalist pessism" – the idea that "rationality is real but rare." Some people are rational some of the time, but no one is rational all the time and some are irrational all the time.

Let's just agree this is true. /4

Sauer's central target is the heuristics-and-biases approach of Tversky and Kahneman, which Sauer calls "[perhaps] the most profound attack on human rationality worth taking seriously." Let's take a look. /5

Here's Tversky and Kahneman (1974) – *the* classic in the genre. In their view, people don't make decisions by solving differential equations or whatever in their heads; people make decisions by applying a small number of heuristics jstor.org/stable/1738360 /6

Heuristics are fast and economical, allowing people to make decisions when it counts with existing cognitive resources. The heuristics are also by and large functional (useful, effective), in that they allow people to make the right decision under a wide range of conditions. /7

But the fast and economical heuristics aren't perfect: there are conditions under which they lead people astray. Moreover, deviations aren't just small and random; they can be significant and systematic – and consequently predictable. /8

The upshot is not that different from Sauer's.

If anything, Tversky and Kahneman come across as *less* pessimistic about rationality: while Sauer says it is "rare", Tversky and Kahneman think people's decisions are "usually effective." /9

Tversky and Kahneman's program lives on in behavioral economics, which Sauer describes dismissively as a "partner in crime," but which is now solidly part of mainstream economics. More here: doi.org/10.1080/135017… /10

Note that behavioral economics – just like Tversky and Kahneman (1974) – allows that people act rationally sometimes or even much of the time.

It does say that people occasionally fail to do so, and that failures are systematic and economically relevant. /11

Anyway, it's an odd declaration of victory in which the position that "won" (Sauer's conclusion in tweet #3) is so similar to the position that "lost" (Tversky and Kahneman's story in tweets #6–7). /12

Or to use another metaphor, it seems to me that the only way to get the conclusion that the pro-rationality side "won" is by moving the goal posts all the way over to the other end of the field. /13

Just one more thing. Sauer concludes we should move on from the question of "whether reason works," and instead focus on how it works and how to improve it. And yet – this is exactly what Tversky and Kahneman (1974) were trying to do. /14

Here are their closing words: "A better understanding of these heuristics and of the biases to which they lead could improve judgments and decisions in situations of uncertainty."

This still sounds right to me. /fin

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