Log inSign up
John D. Cook
39.9K posts
Image
user avatar
John D. Cook
@JohnDCook
Consultant in applied math and data privacy
Houston
johndcook.com
Joined November 2008
250
Following
56.1K
Followers
  • user avatar
    John D. Cook
    @JohnDCook
    Nov 19, 2022
    Pop songs don’t have key changes anymore. tedium.co/2022/11/09/the…
    Image
  • user avatar
    John D. Cook
    @JohnDCook
    Mar 19, 2025
    Harvard is denying admission to students with perfect SAT scores and AP calculus credit, while also admitting students who need remedial math.
    Image
    1M
  • user avatar
    John D. Cook
    @JohnDCook
    May 24, 2024
    Image
    1.8M
  • user avatar
    John D. Cook
    @JohnDCook
    May 22, 2024
    Image
    382K
  • user avatar
    John D. Cook
    @JohnDCook
    Dec 6, 2022
    An AI chatbot is an echo chamber, repeating the data it was trained on. If you trained ChatGPT on all the text you could find before 1880, and asked it what causes malaria, it would tell you bad air.
  • user avatar
    John D. Cook
    @JohnDCook
    Sep 20, 2025
    Image
    Readers added context to this imageReaders added context
    The use of the phrase “vegetative electron microscopy” appears to come from a mistranslation caused by a typo in Farsi, not AI. retractionwatch.com/2025/03/04/veg…
    Context is written by people who use X, and appears when rated helpful by others. Find out more.
    267K
  • user avatar
    John D. Cook
    @JohnDCook
    Jun 27, 2021
    Calcium, magnesium, and iron in cabbage, lettuce, tomatoes, and spinach dropped 80–90% between 1914 and 2018. ncbi.nlm.nih.gov/pmc/articles/P…
    Image
  • user avatar
    John D. Cook
    @JohnDCook
    Feb 23, 2020
    “You should turn that blog post into a journal article.” Translation: You should put in 20x the effort so you can reach 1000x fewer people.
  • user avatar
    John D. Cook
    @JohnDCook
    Jul 14, 2015
    Photos of Pluto in 1930, 1996, and 2015
    Image
  • user avatar
    John D. Cook
    @JohnDCook
    Oct 9, 2024
    Image
    193K
  • user avatar
    John D. Cook
    @JohnDCook
    Nov 13, 2024
    When I was a student, I was amazed to learn that mechanical and electrical systems satisfy the same differential equations. The fact that the systems are ANALOGOUS is why a circuit designed to model a physical system is called an ANALOG system.
    141K
  • user avatar
    John D. Cook
    @JohnDCook
    Apr 19, 2018
    First they ignore you. Then they laugh at you. Then you realize there are good reasons why your naive ideas weren’t immediately embraced, that the world is more complex than you thought.
  • user avatar
    John D. Cook
    @JohnDCook
    Oct 11, 2023
    “What kind of math does your consulting involve?” “Sometimes fancy stuff, but often high school level math.” “Why would anyone hire a professional mathematician to do high school math?” “Because a professional mathematician can wield high school math like a professional.”
    293K
  • user avatar
    John D. Cook
    @JohnDCook
    May 18, 2021
    “When you mix politics with science, you get politics.” — John Barry

New to X?

Sign up now to get your own personalized timeline!

Create account

By signing up, you agree to the Terms of Service and Privacy Policy, including Cookie Use.

Terms·Privacy·Cookies·Accessibility·Ads Info·© 2026 X Corp.
Don't miss what's happening
People on X are the first to know.
Log inSign up
Advertisement
Advertisement