Slate Star Codex

Slate Star Codex
Screenshot of the Slate Star Codex home page prior to deletion
Type of site
Blog
Available inEnglish
Successor(s)Astral Codex Ten
Created byScott Alexander
URLwww.slatestarcodex.com [formerly]
www.astralcodexten.com [currently]
LaunchedFebruary 12, 2013 (2013-02-12)
Current statusActive (as Astral Codex Ten, Slate Star Codex is online but inactive)

Astral Codex Ten (ACX), formerly Slate Star Codex (SSC), is a blog focused on science, medicine (especially psychiatry), philosophy, politics, and futurism. The blog is written by Scott Alexander Siskind, a San Francisco Bay Area psychiatrist, under the pen name Scott Alexander.

Slate Star Codex was launched in 2013 and was discontinued on June 23, 2020. As of July 22, 2020, the blog is partially back online, with the content restored but commenting disabled. The successor blog, Astral Codex Ten, was launched on January 21, 2021.

Alexander also blogged at the rationalist community blog LessWrong, and wrote a fiction book in blog format named Unsong. A revised version of Unsong was published on May 24, 2024.