The Codex

The Codex is a collection of essays written by Scott Alexander that discuss how good reasoning works, how to learn from the institution of science, and different ways society has been and could be designed. It also contains several short interludes containing fictional tales and real-life stories. The essays contained have been widely read within the rationality and effective altruism communities, and have a strong bias towards actually reading the scientific papers being discussed, analysing the arguments closely, and taking the conclusions seriously.

Good and Bad Reasoning

Ar­gu­ment and Analysis

A sequence of essays by Scott Alexander on how arguments work, how to use them, and how to misuse them.

Eight Short Stud­ies On Excuses

Schel­ling fences on slip­pery slopes

In­tel­lec­tual Hip­sters and Meta-Contrarianism

Car­diol­o­gists and Chi­nese Robbers

All De­bates Are Brav­ery Debates

The Virtue of Silence

Prov­ing Too Much

Be­ware Iso­lated De­mands For Rigor

1. Interlude

Tran­shu­man­ist Fables

…And I Show You How Deep The Rab­bit Hole Goes

Cat­e­gori­sa­tion and Concepts

“The essay “How An Algorithm Feels From The Inside” is a gift that keeps on giving. You can get a reputation as a daring and original thinker just by copy-pasting it at different arguments with a couple of appropriate words substituted for one another, mad-libs like. It is the solution to something like 25% of extant philosophical problems.”

Diseased think­ing: dis­solv­ing ques­tions about disease

The Cat­e­gories Were Made For Man, Not Man For The Categories

The non­cen­tral fal­lacy—the worst ar­gu­ment in the world?

Eth­nic Ten­sion And Mean­ingless Arguments

1. Interlude

The Mo­ral Of The Story

Prob­a­bil­ity and Predictions

Nearly everyone is very very very overconfident. We know this from experiments where people answer true/​false trivia questions, then are asked to state how confident they are in their answer. If people’s confidence was well-calibrated, someone who said they were 99% confident (ie only 1% chance they’re wrong) would get the question wrong only 1% of the time. In fact, people who say they are 99% confident get the question wrong about 20% of the time.

It gets worse. People who say there’s only a 1 in 100,000 chance they’re wrong? Wrong 15% of the time. One in a million? Wrong 5% of the time. They’re not just overconfident, they are fifty thousand times as confident as they should be.

The Pyra­mid And The Garden

On Overconfidence

If It’s Worth Do­ing, It’s Worth Do­ing With Made-Up Statistics

Tech­niques for prob­a­bil­ity estimates

Con­fi­dence lev­els in­side and out­side an argument

1. Interlude

The Lo­gi­cian And The God-Emperor

Re­v­erse Psychology

The In­sti­tu­tion of Science

Stud­ies and Statistics


Aquinas famously said: beware the man of one book. I would add: beware the man of one study.

For example, take medical research. Suppose a certain drug is weakly effective against a certain disease. After a few years, a bunch of different research groups have gotten their hands on it and done all sorts of different studies. In the best case scenario the average study will find the true result – that it’s weakly effective.

But there are also about 5 studies that find that the drug is very good, and 5 studies missing the sign entirely and finding that the drug is actively bad. There’s even 1 study finding that the drug is very bad, maybe seriously dangerous.

Be­ware The Man Of One Study

De­bunked And Well-Refuted

Noisy Poll Re­sults And Rep­tilian Mus­lim Cli­ma­tol­o­gists from Mars

Two Dark Side Statis­tics Papers

The Con­trol Group Is Out Of Control

The Cow­pox of Doubt

How Com­mon Are Science Failures?

Learn­ing To Love Scien­tific Consensus

1. Interlude

My IRB Nightmare

The Study of Anglophysics

Re­search and Reviews

Synthesising scientific knowledge to answer a policy question is difficult. This sequence is a series of attempts to do just that, with intricate and winding literature reviews.

0. Much More Than You Wanted to Know

Mar­ijuana: Much More Than You Wanted To Know

Wheat: Much More Than You Wanted To Know

SSRIs: Much More Than You Wanted To Know

Al­co­holics Anony­mous: Much More Than You Wanted To Know

Pre­scrip­tions, Para­doxes, and Perversities

Guns And States

Teach­ers: Much More Than You Wanted To Know

An­tide­pres­sant Phar­ma­coge­nomics: Much More Than You Wanted To Know

1. Interlude

A Story With Zombies

Asches to Asches

Hy­pothe­ses and Hunches

The Atomic Bomb Con­sid­ered As Hun­gar­ian High School Science Fair Project

It’s Bayes All The Way Up

Why Are Trans­gen­der Peo­ple Im­mune To Op­ti­cal Illu­sions?

1. Interlude

The Case Of The Suffo­cat­ing Woman

De­sign­ing the World

Poli­tics and Pragmatics

I Can Tol­er­ate Any­thing Ex­cept The Outgroup

Book Re­view: Albion’s Seed

Albion’s Seed, Genotyped

So­ciety Is Fixed, Biol­ogy Is Mutable

1. Interlude

A Philoso­pher Walks Into A Coffee Shop

The Witch­ing Hour

Eco­nomics and Efficiency

0. Marginally Im­por­tant Econ Questions

Against Tulip Subsidies

Con­sid­er­a­tions On Cost Disease

High­lights From The Com­ments On Cost Disease

The Price Of Glee In China

Things Prob­a­bly Matter

How The West Was Won

1. Interlude

The Lizard Peo­ple Of Alpha Dra­co­nis 1 De­cided To Build An Ansible

A Modern Myth

Fu­tur­ism and Forecasting

A sequence of futurism discussion that includes AGI, brain emulations and the Fermi paradox.

Su­per­in­tel­li­gence FAQ

AI Re­searchers On AI Risk

Should AI Be Open?

SSC Jour­nal Club: AI Timelines

Where The Fal­ling Ein­stein Meets The Ris­ing Mouse

Don’t Fear The Filter

Book Re­view: Age of Em

As­cended Econ­omy?

1. Interlude

G.K. Ch­ester­ton On AI Risk

[REPOST] The Demiurge’s Older Brother

Com­mu­nity and Cooperation

In Fa­vor of Nice­ness, Com­mu­nity, and Civilization

Guided By The Beauty Of Our Weapons

The Ide­ol­ogy Is Not The Movement

Archipelago and Atomic Communitarianism

Med­i­ta­tions On Moloch

1. Interlude

Five Planets In Search Of A Sci-Fi Story

It Was You Who Made My Blue Eyes Blue

Epilogue

Parables and Prayers

Burdens

The Parable Of The Talents

No­body Is Perfect, Every­thing Is Commensurable

1. Interlude

An­swer to Job

Univer­sal Love, Said The Cac­tus Person

The God­dess of Every­thing Else