# Quote — Nassim Nicholas Taleb, The Black Swan

> If you want to get an idea of a friend's temperament, ethics, and personal elegance, you need to look at him under the tests of severe circumstances, not under the regular rosy glow of daily life. Can you assess the danger a criminal poses by examining only what he does on an ordinary day? Can we understand health without considering wild diseases and epidemics? Indeed the normal is often irrelevant.

- Author: [Nassim Nicholas Taleb](https://www.leafyquotes.com/nassim-nicholas-taleb.md)
- Book: [The Black Swan](https://www.leafyquotes.com/nassim-nicholas-taleb/the-black-swan.md)
- Source: [Wikiquote](https://en.wikiquote.org/wiki/Nassim_Nicholas_Taleb#The_Black_Swan:_The_Impact_of_the_Highly_Improbable_(2007)) ([CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/))
- Quote page: https://www.leafyquotes.com/nassim-nicholas-taleb/the-black-swan/if-you-want

## More from this book

> There is no effective difference between guessing a variable that is not random, but for which information is partial or deficient (...), and a random one (...). In this sense, guessing (what I don't know, but what someone else may know) and predicting (what has not taken place yet) are the same thing.

p. 142 — [Quote page](https://www.leafyquotes.com/nassim-nicholas-taleb/the-black-swan/there-is-no-effective.md)

> History is opaque. You see what comes out, not the script that produces events, [...] The generator of historical events is different from the events themselves, much as the minds of the gods cannot be read just by witnessing their deeds.

p. 8 — [Quote page](https://www.leafyquotes.com/nassim-nicholas-taleb/the-black-swan/history-is-opaque.md)

> Categorizing is necessary for humans, but it becomes pathological when the category is seen as definitive, preventing people from considering the fuzziness of boundaries, let alone revising their categories.

p. 15 — [Quote page](https://www.leafyquotes.com/nassim-nicholas-taleb/the-black-swan/categorizing-is-necessary.md)