All science mentioned in Methods is standard science except where otherwise specified (IIRC, the only two uses of nonstandard theories are Barbour’s timeless physics in Ch. 28 and my own timeless decision theory in Ch. 33).  Wherever possible, I have mentioned standard terminology inside the book to make Googling easier.  At some future point I may compile a complete list for all the scientific references in Methods, but this has not yet been done.

Here’s a listing for the first five chapters:

  • Ch. 1:  The Feynman quote Harry refers to can be found here, around half-way down the page, starting with “Philosophers, incidentally…”  Cold reading is a standard practice of bogus psychics, regularly duplicated by skeptics to prove that no mind-reading is required.  Bending spoons is even easier.  When Harry thinks about how his father is refusing to test magic because that would feel like affiliating with a low-prestige idea, he is taking the Hansonian-cynical view of ‘belief’ as affiliation.  Also, stacking two-by-fours or old Kleenex boxes on the back shelves of a bookcase, does in fact work for making the back row of titles readable – I do this in my own home.
  • Ch. 2:  “You’d think there’d be some kind of more dramatic mental event associated with updating on an observation of infinitesimal probability -”  In a Bayesian sense, seeing an observation to which you assigned very low probability can (and should) produce very large shifts in belief.  For mathy readers, reading the Intuitive Explanation of Bayesian Reasoning may help in appreciating what Harry is talking about – how probability theory behaves in the presence of an “impossible” observation.  (For non-mathy readers, a huge rewrite of that document is currently underway which should make it much more easily accessible.)  In Harry’s “You turned into a cat!” speech, “That’s not just an arbitrary rule, it’s implied by the form of the quantum Hamiltonian!” refers to Conservation of Energy being the Noether’s Theorem conjugate of the laws of quantum mechanics being invariant under translation in time.  There is no simple way whatsoever to explain this, except to remark that Conservation of Energy seems built into the laws of physics on an extremely deep level – it’s not just a matter of not knowing any particular force that violates it; we have reason to believe that no force should violate it.  And for the benefit of any second-grade math teachers out there, LOGARITHMS.
  • Ch. 3:  “Comparing Reality to Its Alternatives” is the title of a paper by Kahneman and Dale Miller, describing (among other things) how people sometimes try to understand the real world by comparing it to something else, like an ideal perfect situation.  A more directly on-topic paper would’ve been Miller’s “Counterfactual thought, regret, and superstition:  How to avoid kicking yourself” but I think I confused those two titles when I was writing Ch. 3.  Also, bystander effect here and here, and diffusion of responsibility.
  • Ch. 4:  Efficient market hypothesis.  Arbitrage.  Fermi calculations.  If you’ve ever been tempted to invest in a mutual fund, or even worse, try to pick stocks yourself, then for the love of Merlin DON’T until you are thoroughly steeped in the basic reasons why markets are, to a first approximation, anti-inductive – if real estate prices “have always gone up”, this says very little about whether they’ll keep on going up in the future.
  • Ch. 5:  The fundamental attribution error.  Also known as “correspondence bias”.  I think the chapter did a pretty good job of illustrating this one, so I shalln’t say anything more.

To learn almost everything that Harry knows, the best current free online solution is to read the Sequences at – two years of blog posts that tried to introduce just about everything that I thought a rationalist needed to know as of 2007, starting with basic theory of knowledge, Bayesian probability theory, cognitive biases, evolutionary psychology, social psychology, and going on into the more arcane realms of reductionism and demystified quantum mechanics.  Believe it or not, Harry is only allowed to draw on around half of the easier Sequences – if he knew all of them, he would be too powerful a character and break the story.

For those of you who prefer traditional books, I’m trying to write one – though the project is currently on hold while working on CMR.  Meanwhile, some good general intros are, in order of technical difficulty:

Fun fact:  When Harry thinks about something scientific, I require myself to write the description from memory, so that I’m not giving him an unrealistic degree of recall.  For example, in Ch. 2 Harry quotes Feynman talking about what philosophers say is absolutely required.  The original quote in the Feynman lectures uses the phrase ‘absolutely necessary’.  I fact-check afterward to make sure there’s no invalidating errors, but not while writing the first draft.  When I’m writing Hermione’s point-of-view, I look up the original beforehand to simulate her perfect recall.