<p>I have been quite astonished by this nonsensical yet lasting quarrel. You didn't find how they disagree because they don't disagree. The sole difference is that if asked "<strong><em>are human rational ?</em></strong>", Gigerenzer answers "<strong><em>yes</em></strong>", Kahneman answers "<strong><em>no</em></strong>". </p>

<p>However, their model of human reasoning are consistent with each other. They just don't use the word "rational" in the same way. </p>

<p>When asked whether humans are rational, Gigerenzer understands the question as "<strong><em>Are human cognitive mecanisms fitted to the environment ?</em></strong>", whereas Kahneman understands this question as "<strong><em>Are human taking decisions that maximize their utility function ?</em></strong>". Kahneman study decisions, and he finds that they are not good/not efficient (i.e., not rational). Gigerenzer study reasoning mechanisms (his heuristics), and he argues that those mechanisms are good/efficient (i.e, rational). Decisions and mechanisms are not the same thing.</p>

<p>If you ask Gigerenzer whether humans take decisions that maximize their utility function, he will happily answer "<strong><em>No</em></strong>". Indeed, Gigerenzer wants people to take better decisions, but he will not call those "more rational decisions".
If you ask Kahneman whether human cognitive mecanisms are adapted to the environment, he will happily answer "<strong><em>Obviously, because evolution is true</em></strong>". To me, Kahneman's definition of rationality makes much more sense. </p>

<p>For a more extended discussion, you can find the following paper which settles the question on google scholar : Samuels, R., Stich, S., &amp; Bishop, M. (2012). Ending the Rationality Wars. Collected Papers, Volume 2: Knowledge, Rationality, and Morality, 1978-2010, 2, 191.</p>

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2018-01-06T13:20:22.693Z
That paper didn't seem end the war though. Apparently G published another book ("Risk Savvy", in 2014 or so)  that the press interpreted as another salvo: https://www.theguardian.com/science/2014/jun/01/nudge-economics-freakonomics-daniel-kahneman-debunked
got trolled too much this week
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2018-01-06T13:29:39.077Z
Also for G's 2015 one-para explanattion of the dispute: http://andrewgelman.com/2015/04/17/gigerenzer-logical-rationality-vs-ecological-rationality/ That seems to be exactly what you describe in your 3rd para.
got trolled too much this week
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2018-01-06T14:04:04.163Z
And something more substantive coming from K's side: https://jasoncollins.org/2014/09/24/kahnemans-optimistic-view-of-the-mind/
got trolled too much this week
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2014-09-22T16:15:37.117Z
2015-12-09T13:59:41.683Z
2015-12-09T13:59:41.683Z
Timothée Behra
<p>I have found many allusions to this feud, e.g. from <a href="http://nickdunbar.net/2012/05/23/thinking-fast-and-slow-by-daniel-kahneman/">http://nickdunbar.net/2012/05/23/thinking-fast-and-slow-by-daniel-kahneman/</a> and in Kahneman's trade book "Thinking, Fast and Slow". However, I have not found any concise explanation of what Kahneman and Gigerenzer actually disagreed on, other than that Gigerenzer felt that some of the Kahneman/Tversky biases were artefacts of their method and Kahneman/Tversky disagreed with this.</p>

<bias>
What differences of opinion led to the Kahneman-Gigerenzer feud?
user1205901 - Слава Україні
# What differences of opinion led to the Kahneman-Gigerenzer feud?

(Asked by: username_0 on 2014-09-19)

I have found many allusions to this feud, e.g. from <http://nickdunbar.net/2012/05/23/thinking-fast-and-slow-by-daniel-kahneman/> and in Kahneman's trade book "Thinking, Fast and Slow". However, I have not found any concise explanation of what Kahneman and Gigerenzer actually disagreed on, other than that Gigerenzer felt that some of the Kahneman/Tversky biases were artefacts of their method and Kahneman/Tversky disagreed with this.

**Tags:** bias


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## 1 answers

### Answer by username_1 on 2014-09-22. Score: 12 | Accepted answer

I have been quite astonished by this nonsensical yet lasting quarrel. You didn't find how they disagree because they don't disagree. The sole difference is that if asked "***are human rational ?***", Gigerenzer answers "***yes***", Kahneman answers "***no***".

However, their model of human reasoning are consistent with each other. They just don't use the word "rational" in the same way.

When asked whether humans are rational, Gigerenzer understands the question as "***Are human cognitive mecanisms fitted to the environment ?***", whereas Kahneman understands this question as "***Are human taking decisions that maximize their utility function ?***". Kahneman study decisions, and he finds that they are not good/not efficient (i.e., not rational). Gigerenzer study reasoning mechanisms (his heuristics), and he argues that those mechanisms are good/efficient (i.e, rational). Decisions and mechanisms are not the same thing.

If you ask Gigerenzer whether humans take decisions that maximize their utility function, he will happily answer "***No***". Indeed, Gigerenzer wants people to take better decisions, but he will not call those "more rational decisions".
If you ask Kahneman whether human cognitive mecanisms are adapted to the environment, he will happily answer "***Obviously, because evolution is true***". To me, Kahneman's definition of rationality makes much more sense.

For a more extended discussion, you can find the following paper which settles the question on google scholar : Samuels, R., Stich, S., & Bishop, M. (2012). Ending the Rationality Wars. Collected Papers, Volume 2: Knowledge, Rationality, and Morality, 1978-2010, 2, 191.

> **Comments:**
> **username_2**: That paper didn't seem end the war though. Apparently G published another book ("Risk Savvy", in 2014 or so)  that the press interpreted as another salvo: https://www.theguardian.com/science/2014/jun/01/nudge-economics-freakonomics-daniel-kahneman-debunked  
> **username_2**: Also for G's 2015 one-para explanattion of the dispute: http://andrewgelman.com/2015/04/17/gigerenzer-logical-rationality-vs-ecological-rationality/ That seems to be exactly what you describe in your 3rd para.  
> **username_2**: And something more substantive coming from K's side: https://jasoncollins.org/2014/09/24/kahnemans-optimistic-view-of-the-mind/  

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