Scott Alexander

Scott Alexander, the pen name of Scott Siskind, is an American psychiatrist and prolific blogger whose work has profoundly influenced online discourse on science, philosophy, and public health. Born in 1984, Siskind earned his medical degree at the University of Texas Southwestern Medical Center and completed his residency in psychiatry at the University of Michigan, where he also began writing about mental health and rationalist thinking. In 2013 he launched the blog Slate Star Codex, a wide‑ranging forum that combined personal essays, detailed medical explanations, and deep‑dives into controversial topics such as vaccination, mental illness, and the ethics of artificial intelligence. The blog quickly amassed a devoted readership among scientists, clinicians, and members of the rationalist community, earning praise for its meticulous citations, thoughtful humor, and willingness to tackle complex issues without resorting to sensationalism. Siskind’s willingness to reveal his professional background lent credibility to his medical commentary, while his candid discussion of his own struggles with depression and anxiety provided a rare, humanizing perspective on mental health. In 2020, following a public controversy surrounding a New York Times article that threatened to reveal his identity, he retired Slate Star Codex and relaunched the site as Astral Codex Ten, a Substack newsletter that continues to explore interdisciplinary topics with the same rigor and wit. Throughout his career Siskind has emphasized the importance of intellectual humility, encouraging readers to update their beliefs in light of new evidence and to engage in civil discourse despite ideological differences. His influence extends beyond his blog; he has been cited in academic papers, contributed to discussions on bioethics, and inspired a generation of online writers to adopt a more evidence‑based approach to public debate. Despite his online fame, Siskind remains relatively private about his personal life, preferring his work to speak for itself while advocating for better mental health awareness and the responsible communication of scientific findings.