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I've seen a theory that the mistakes Pemulis makes are intentional, and signal that he isn't as smart as he thinks and that he doesn't really have everything in control.

I'm not sure; clearly DFW had some math aptitude but these also could have been honest mistakes. Presumably it would have been harder for editors to check these things in the 90s.

The probability error seems harder to explain and likely just a mistake.

Edit - While searching a bit more about this, I found an interesting perspective on a message board:

> The main thing that I think argues for Pemulis not being as smart as he thinks he is, is that he is the analogue of Polonious from Hamlet. In Hamlet, the court jester (the "fool") is actually really wise and always speaks the truth (=Mario), while the King's supposedly "wise" counselor, Polonious, actually gets everything wrong.

I find that pretty compelling. I hadn't really thought about deeper correspondences with Hamlet beyond Hal and his parents.

https://infinitesummer.org/forums/viewtopic.php?f=12&t=471

They are purposeful, I don't think Pemulis ever gets one thing right in the novel. His explanation of Annular Fusion is a good example, unless you also want to make the case that Wallace got the made up science wrong as well. Pemulis grew up in a place where he was generally the smartest person around and was able to bluff his way through life without much effort. Then he got a scholarship to somewhere with actual expectations and standards but Pemulis kept on with his lazy ways. Pemulis is probably smart but his laziness and arrogance keep him from ever achieving his own intelligence, he is forever lobbing but is a bit too slow to get to the net in time.

Vast majority of character's are well explained and the answers are all in the novel, just need to look at their childhood and upbringing.

No one of any level of math skill would mistake the the derivative of x^n as nx + x^n-1. There's no way DFW messed that up, but it's also a pretty bizarre mistake to have a character make if they're supposed to be making mistakes.
Perhaps my favorite deliberate error in arithmetic is from Winston Groom's Forrest Gump, during the protagonist's tour in Vietnam:

> I am the machine gun ammo bearer, cause they figger I can carry a lot of shit on account of my size. Before we lef, a couple of other fellers axed if I would mind carryin some of their han grenades so’s they could carry more orations, an I agreed. It didn’t hurt me none. Also, Sergeant Kranz made me carry a ten-gallon water can that weighed about fifty pounds.

Unlike Forrest, the reader knows a gallon of water weighs roughly eight pounds and is not spared the extent of his burden.

Would Pemulis be Polonius though? If he were the advisor to the king, then the king would more likely be Tavis, not Hal.

I do like the idea of Mario as a court jester though.

Wouldn't Pemulis' mathematical errors be consistent with how Infinite Jest begins? I.e., he has some sort of degenerative condition directly or indirectly associated with exposure to strange mold found in the basement of his childhood home?
And the title
Maybe DFW wasn't as smart as he thought he was.
DFW also wrote Everything and More: A Compact History of Infinity -- an uncritical review of Cantor's work, which was absolutely loaded with errors.

Rudy Rucker wrote a scathing review here: https://www.rudyrucker.com/oldhomepage/wallace_review.pdf

I actually read Everything and More and it's probably even worse than that. Though I'll admit that I'm a little bit biased; I'm a sort of Aristotelian Realist or even a Finitist when it comes to mathematics, and I view Cantor's hierarchy of infinities as... well... schizo at best.

Personally I don't agree with that review at all, and I loved Everything and More. I'm even somewhat of a "finitist" myself mathematically, but I think you can just view the whole hierarchy of infinities as a finite mode of description, and get utility from it without worrying about the "reality" of the whole thing. But that's a bit of an aside.

The review-writer clearly hates the book before he even gets to the mathematics. The whole book is striking a middle ground between expressing every step of mathematical rigor, and describing in a more literary way how to feel about these concepts. All of these "errors" are just the author passing over a point in less detail than you would want from a text on set theory. I thought it was great, and for anyone who enjoys both set theory and Infinite Jest, I would strongly recommend the book.

I understand that some people don't like it, but it should be viewed as "controversial" rather than "everyone agrees that it's riddled with errors".

> "He incorrectly suggests that the axiom of choice is used for Cantor's diagonal argument"

This alone is a pretty substantial, even foundational, error.

The author of the review, Rudy Rucker, is a sort of cult/underground author of math-heavy science fiction. I don't think he's opposed to framing things in a literary way, so long as it's not misleading or falsely dramatized. Like, e.g., Godel ending his days in some sort of forced confinement, as DFW seems to have suggested?

> The whole book is striking a middle ground between expressing every step of mathematical rigor, and describing in a more literary way how to feel about these concepts

I really hate this. If you don't care to understand something, why would you want to absorb the feelings that somebody else thinks you should have from understanding it? It reminds me of all the cringey posturing that undergrads engage in because their English professor mentioned a couple of philosophers during lectures and it totally changed their wardrobe.

As a mathematician, I think it is very hard to write popular expositions of mathematics. It is acceptable and even necessary to skip the technical details and replace rigorous definitions with intuitive explanations, but it should be done with great care to avoid statements that are plainly wrong and only introduce more confusion. I think the majority of texts on complicated mathematics that target the general audience suffer from this issue.

The review mentions some very unfortunate errors that are not "passing over a point in less detail": suggesting that Cantor's diagonal argument depends on the AC and that CH is equivalent to c = 2^ℵ₀.

I wasn't familiar with the book and had just read the review; I wouldn't blame the author, but the publisher should have contacted someone for proofreading.

I read it and it made me pretty upset... Wallace clearly got way out over his skis and simply shouldn't have been writing about the topic. There were way too many moments interspersed throughout the book where it was obvious that he didn't understand what he was talking about or trying to prove. I think one of the key lessons to be learned from the study of mathematics is intellectual honestly and humility. It felt like Wallace hadn't learnt that lesson and had something to... ahem... prove?
The problem with Everything and More is not because it is "uncritical"; it's that DFW didn't understand it and was "not even wrong" when explaining it. Even if you choose not to engage with Cantor's hierarchy of infinities because you don't find it interesting or relevant to the (finite or smaller infinite) sets you care about, there's nothing wrong with it as mathematics.
Yeah, I like DFW (although mainly from essays and interviews) and thought this book was not good. Tangentially, I didn’t really like Rucker’s book on infinity either. I can’t remember why exactly, but it didn’t match up with other math popularizers (eg, Strogatz, Nahin).
About half way through the book he tries to do an epsilon delta proof and completely gets the logic wrong. Ignoring any philosophical outlook, this is not a great math book.
Maybe he "just" got it wrong. Maybe they're typos, and the manuscript was correct. Or...

Maybe Pemulis gave Hal an obviously wrong derivative, and when uncorrected, drove Pemulis to abruptly end the tutoring. Maybe Pemulis said it right but Hal heard it wrong. Or...

Maybe it's "just" another sign they're in an alternate universe where even the math is different. That's pretty much how I feel about it

> Maybe it's "just" another sign they're in an alternate universe where even the math is different

Unlike physics, there are no conceivable alternate universes with different math. That's what's so cool about math: it could not possibly be any different. There could be alternate universes where they've discovered different amounts of it, or named the discoveries different things, but everything that is "wrong" in math in our universe is universally (multiversally?) wrong.

> the Mean Value Theorem for integrals is a theoretical tool for proving the existence of this particular x'. It does not, however, offer any method of finding the value of x'. Therefore, it is difficult to imagine how the Mean Value Theorem for integrals could be employed in Pemulis' Eschaton calculations.

Knowing the character, at least this one could be explained as yet another parlour trick from Michael Pemulis. God knows how he actually calculated those values.

> Again, Mike Pemulis is lecturing Hal, but this time he is helping Hal prepare for the college board exams. Pemulis states that for the function x^n, the derivative is nx + x^(n-1). In fact, the correct expression is nx^(n-1). This, too, may be a typographical error.

Another possibility is that Pemulis is simply bad at math :D

What’s interesting about this is that it used to be far more common for most technical people to be pretty well versed in basic calculus. A frightening number of software engineers don’t really understand calculus. But back in the 90s most engineers, even software folks who may likely have come from an EE background, would have had the basics down pretty well. DFW was writing for an audience with a potentially much higher mathematical literacy than today.

The probability that this “mistake” is intentional is related to how likely an informed reader would be to recognize this mistake.

Reading the DFW biography, Every Love Story Is a Ghost Story, it said that there were hundreds of cases where the editor claimed something was a typographical error, and DFW insisted that actually it was precisely how he meant it to be. They went back and forth for months, with the publisher eventually charging DFW a fee for all the extra labor involved.

So... we can't know for sure, but there's a strong case that any particular little weird error, DFW intended it to be this way. Especially for a "basic calculus" issue like this, for someone who wrote a whole book on the mathematical history of infinity. (Which arguably has its own errors, but those tend to fall more in the category of simplifications for the lay reader, IMO.)

Yeah, that looks to me far more likely to be deliberate. The obvious comedy of the situation is someone taking himself to be well-versed enough to be giving a lecture while in fact being an incompetent buffoon.
I look forward to the day another book makes me feel like IJ - even with the mathematical flaws :)
Agreed. It was really a revelation to me. Looking back now, it's clear that I started reading it as a status seeking thing. I thought my intellectual friends (and especially girlfriends) would think it was cool that I actually read the whole thing (which nobody else in our circle had actually managed yet). But then it turned out to really affect me deeply.

I read it again about a decade later after all those games were over for me, just for myself, and loved it even more that time.

For some people, it just really does hit a nerve!

Have you read "Gravity's Rainbow" by Thomas Pynchon? If not, it's worth checking out.
Yes, once you read IJ, it is very hard to find another book like it. It is almost as if IJ refers to itself.
House of Leaves, perhaps?
What race is Hal?
Mathematically, the odds of getting exactly N heads after flipping a fair coin 2N times is surprisingly high - it asymptotically approaches 1/sqrt(pi * N) as N becomes large. For the problem in IJ, this comes out to 1/(3.14 * 54) which is 0.076776 - not far from the exact value of 0.076599. As another example, if you flip a fair coin 1000 times, you’ll get exactly 500 heads about 2.5% of the time.

The proof is also similarly easy: it’s a straightforward application of Stirling’s approximation to the formula (2N!)/(N!*N!)/2^(2N).

Has anyone actually read Infinite Jest in its entirety? I got about 50 pages in and I'm pretty sure I got the jist of it from that. The constant slog into minutia and clunky grammar made it very slow reading for me. There were some funny parts but overall the effort didn't feel worth it.

I tore through Gravity's Rainbow (mentioned in another thread).

I enjoyed Infinite Jest.

I think it's good book if you are someone who HAS to know all the details.

The book itself criticizes this way of thinking, while letting you in the all the details you could want. (the footnotes especially)

I get the sense that the writing style is a metaphor and part of it for sure.

I also really like many of the subtle ideas the book presents.

Though like many "post modern novels", it's not for everyone. If intentionally dull parts are not your thing, that's perfectly fine IMO.

I had a very easy/boring job and where during last few month I spent most of my time reading infinite jest after finishing the days work. I really loved it but I probably won't read it again anytime soon, there's a pretty substantial upfront time investment you have to make before it starts getting enjoyable to read.

Though once you lock in with the world and flow of infinite jest it gets pretty amazing, I wish I had more people to talk to about it without coming off as a pretentious jackass. Also it's far more enjoyable to read it as an ebook where you can jump instantly from the text to footnotes and look up unfamiliar words. Reading the physical copy seems torturous to me.

Yeah definitely, multiple times. But I feel you! The first time I read it it took me months to make it past the first couple hundred pages. But once you get far enough in everything starts to gel and it gets really fun.
At about page 300 it starts to pay off hard and you fly through the rest. I definitely recommend giving it another go.
Yes I have and I think I'm the only person not lying about that fact.
I totally agree, IJ might be the single most disappointing book I've read given the extreme hype around it. The writing style felt very self-indulgent and annoying. The funny/clever parts rarely seemed amusing to me.

Enough people say they love the book that it's probably just a style thing that didn't click for me, but I regret how much time I spent slogging through the book and never bothered to finish it.

Cool. We care. Keep talking.
This isn't the only example of a debate over intentionality in mistakes in Infinite Jest. The book's french is also littered with errors so egregious that most think they could only have been intentional [1].

[1] https://ask.metafilter.com/116066/French-language-in-Infinit...

I haven’t read IJ in a while, but I don’t think I agree with the first one. Unless he specifically said that each player has an equal chance of winning, I would not assume that to be the case.
Interesting! But then it seems like he would have said it a bit differently, that the odds of that particular tournament with those specific players ending in a tie were much lower.
> Intentional math errors in David Foster Wallace's work

The actual title of this piece is "Dubious Math in Infinite Jest". There is no suggestion, in the title or the contents, that the errors are intentional. In the author's words:

> As I have said, I have no theories to explain the existence of these errors.

You’re right. I’ve just changed the title of the article adding “(un)” to the beginning. I can’t prove the errors are intentional, but given the author’s reputation it would surprise me if they weren’t.
Yes, the title entered here on HN is misleading and misrepresents the actual article.
David Foster Wallace & David Sedaris are both "consummable media" in that they're pleasurable to read... but you walk away from their material and just feel empty (except for esoteric connections you might've woven into your own storyline). With any expert technical knowledge, you'll quickly know that Wallace wasn't any expert.

I've only read Infinite Jest once, and would have edited it differently myself — but the scenes on addiction are powerful, stressful, and accurate (as somebody over a decade california clean). Pale King is better prose, but in both cases DFW isn't a "complete" author — he expects too much from his readers.

At least in Sedaris' case, he keeps his prose brief =D