Scott Alexander (born 1984) is a pseudonymous American psychiatrist and blogger. Alexander is the author of the blogs Slate Star Codex (SSC) and its successor Astral Codex Ten (ACX), and a contributor—originally under the user name Yvain—to the community blog LessWrong.


Alexander studied philosophy as an undergraduate, and in 2012 graduated from University College Cork School of Medicine, Ireland. He did his residency at St. Mary Mercy Hospital in Michigan, United States. He specializes in treatment-resistant depression and his areas of interest within psychiatry include chronotherapy, behavioral genetics, and the ontology of psychiatric disorders. One of Alexander's blog posts[1] was subsequently revised and published in Pharmacology Research & Perspectives.[2]

Before establishing his own practice, Lorien Psychiatry, Alexander worked at LifeStance Health (formerly Pacific Coast Psychiatric Associates) and served as Senior Health Researcher of MetaMed, a medical consulting company.[3][4][5] Since 2021, Alexander has been on the advisor board of the Qualia Research Institute.

Blogging career

SSC launched in early 2013. Except for a missing letter "n", the name is a perfect anagram of Alexander's name. (The blog's header displayed an image of the missing letter "to restore cosmic balance"[6])  SSC was shut down in mid-2020, after a New York Times journalist ignored Alexander's request not to reveal his true identity.[7][8]

ACX launched in early 2021 - its name is a perfect anagram of "Scott Alexander". It is hosted on Substack, an online publishing platform. Although readers can opt for a paid subscription, Alexander notes that "[a]ll important ACX content is and always will be free."[9]

In November 2021, Alexander announced ACX Grants, an initiative to award a total of $250,000 in small grants to promising projects, with a minimum of paperwork.[10] The budget grew to $1.3 million after several outside funders contributed to the initiative. Alexander announced the results in late December. Out of 656 submissions, 38 projects received funded; the median grant was $40,000.[11]

Influence and reception

Alexander's writings, particularly his SSC posts and some of his earlier LessWrong posts, have been highly influential within the rationality and effective altruism communities. He has received praise from many prominent figures, including Bryan Caplan,[12] Tyler Cowen,[13] Steven Pinker,[14] and others.[15][16][17][18]

Further reading

Bensinger, Rob (2015) The Library of Scott Alexandria, LessWrong, September 13.
A selection of Alexander's writings from SSC, LessWrong, and LiveJournal.

Crawford, Jason (2021) Who is Scott Alexander and what is he about?, Jason Crawford’s Blog, February 13.
A selection of Alexander's writings from SSC.

Ngo, Richard (2020) EA reading list: Scott Alexander, Effective Altruism Forum, August 3.

Astral Codex Ten. Alexander's current blog.

Slate Star Codex. Alexander's previous blog.

LiveJournal blog. A complete archive of Alexander's early blog.

Scott Alexander. Effective Altruism Forum account.

rationality community

  1. ^

    Alexander, Scott (2015) Prescriptions, paradoxes, and perversities, Slate Star Codex, April 30.

  2. ^
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  4. ^

    Siskind, Scott (2018) Scott Siskind, MD, Pacific Coast Psychiatric Associates.

  5. ^

    WebMD Care (2021) Scott Alexander Siskind, WebMD Care.

  6. ^

    Alexander, Scott (2013) You’re probably wondering why I’ve called you here today, Slate Star Codex, February 12.

  7. ^
  8. ^

    Alexander, Scott (2021) Still alive, Astral Codex Ten, January 21.

  9. ^

    Alexander, Scott (2021) What is Astral Codex Ten?, Astral Codex Ten.

  10. ^

    Alexander, Scott (2021) Apply for an ACX Grant, Astral Codex Ten, November 11.

  11. ^

    Alexander, Scott (2021) ACX Grants results, Astral Codex Ten, December 28.

  12. ^

    Caplan, Bryan (2014) Read Scott Alexander, EconLog, October 28.

  13. ^

    Cowen, Tyler (2018) Holding up a mirror to intellectuals of the left, Bloomberg, April 24.

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    Friedman, David D. (2020) Slate Star Codex and The New York Times, Ideas, June 26.

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  18. ^

    Aaronson, Scott (2020) Pseudonymity as a trivial concession to genius, Shtetl-Optimized, June 23.