The Quest For Caffeine You Can Have At Night
Astral Codex Ten Podcast
Since the beginning of time, mankind has yearned to drink a cup of coffee at 5 PM and go to sleep at 10. But now there’s an entire scientific subfield and several companies pandering to this absurd fantasy. Here’s a simplified diagram of caffeine metabolism: Caffeine is converted to a different stimulating chemical called paraxanthine by a liver enzyme called CYP1A2, over a half-life of ~5 hours. Then the same enzyme converts paraxanthine into other non-stimulating chemicals that don’t matter, over a half-life of about three hours. has graphed the total effective concentration over...
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The Foothills Of Bay Area House Party
Astral Codex Ten Podcast
[previously in series: , , , , , , , , ] Paul Graham that every city sends a message. New York says you should make more money. Berkeley says you should live better. Boston says you should be smarter. People shouldn’t decide on a permanent residence until they’ve lived in several cities and understand their differing psychological effects. San Francisco sends a message too. It speaks it in a cacophony of dissonant voices, some sounding like the hissing of snakes, others like the chittering of insects. “You should pierce the veil,” it says, with a faint accent which you are not...
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MacGregor The Bridge Builder
Astral Codex Ten Podcast
Old Scottish joke: A man at the bar is complaining: “You see that bridge there? I built it with my own hands! But do they call me ‘MacGregor The Bridge-Builder’? No! And I raised five beautiful children! But do they call me ‘MacGregor The Child-Raiser’? No! But, you fuck one sheep . . .” Has MacGregor been treated unfairly?
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Open Questions On Open Weights
Astral Codex Ten Podcast
Last month, some of Silicon Valley’s biggest companies signed supporting open-weights AI. Open weights AI is like open-source software, where the creator makes the raw code publicly available for free download. It’s good insofar as it’s the only way an AI can truly be the user’s property, as opposed to something that companies like OpenAI or Anthropic temporarily let you use subject to their corporate guidelines and increasingly-nanny-state-like restrictions. If AI becomes the linchpin of the future, open weights AI feels like the sort of thing that could be the difference between...
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The Beauty Of Settled Science
Astral Codex Ten Podcast
Commenters convinced me I made a subtle mis-step in my framing of . My framing emphasized that social priming studies had failed to replicate, but that many other subfields of psychology hadn’t. This naturally led commenters to point to failed replications in other subfields. Although none of these were as bad as social priming, few or none were entirely problem-free. Instead of emphasizing the difference between social priming and other subfields, I should have emphasized the difference between settled science and novel research. Here are some of my favorite psychology findings:
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Does Forecasting Have Room At The Top?
Astral Codex Ten Podcast
Superforecasting is the art/science/sport of predicting the future - for example, who will win elections, which countries will fight wars, when key technologies will be discovered. Over the past few years, it went from an obscure academic subfield to a multibillion dollar industry in the form of prediction markets. More recently, AI superforecasters have come close to the accuracy of top humans, and their performance is rising rapidly. In a year or two, we’ll see one of the following patterns: Either humans have already come close to some fundamental limit on the predictability of world...
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Your Book Review: The Epic Of Gilgamesh
Astral Codex Ten Podcast
Finalist #4 in the Book Review Contest [This is one of the finalists in the 2026 book review contest, written by an ACX reader who will remain anonymous until after voting is done. I’ll be posting about one of these a week for several months. When you’ve read them all, I’ll ask you to vote for a favorite, so remember which ones you liked] Introduction: He Who Saw the Deep I’ve been thinking, lately, about the first epic story ever written. If you know anything about the Epic of Gilgamesh, you know that it’s old. This is part of why I find it so interesting, but not the only part. The...
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Highlights From The Discourse On The Hugging Face Incident
Astral Codex Ten Podcast
[Original . Like a Highlights From The Comments post, but including discussion from around the Internet.] Roon is an OpenAI researcher whose popular Twitter presence has catapulted him to the status of extremely-unofficial company representative. He seems spooked:
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Links For July 2026 (Part 2)
Astral Codex Ten Podcast
[continued from Part 1 . I haven’t independently verified each link. On average, commenters will end up spotting evidence that around two or three of the links in each links post are wrong or misleading. I correct these as I see them, and will highlight important corrections later, but I can’t guarantee I will have caught them all by the time you read this.]
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Psychology Research Is Mostly Fine
Astral Codex Ten Podcast
People act like the replication crisis has discredited psychology, that the field is now widely agreed to be a sham, that it can be uncontroversially held up as an example of science gone wrong. These statements are often made in the broadest possible terms:
info_outlineOkay, let’s do this! Link is here, should take about twenty minutes. I’ll close the form on Monday 10/21 and post results the following week.
I’ll put an answer key in the comments here, and have a better one including attributions in the results post. DON’T READ THE COMMENTS UNTIL YOU’RE DONE.