David Deutsch (DD) wrote in Quantum theory, the Church-Turing principle and the universal quantum computer (1985), p. 3:

Church (1936) and Turing (1936) conjectured ... This is called the ‘Church-Turing hypothesis’; according to Turing,

Every ‘function which would naturally be regarded as computable’ can be computed by the universal Turing machine. (1.1)

And from Deutsch's references (p. 19):

Turing, A. M. 1936 Proc. Lond. math. Soc. Ser. 2, 442, 230.

Now we'll compare with Turing's paper: On Computable Numbers, With An Application To The Entscheidungsproblem (1936), p. 230:

the computable numbers include all numbers which could naturally be regarded as computable.

Turing wrote "numbers", but DD misquoted that as "function". Turing also wrote "could" which DD misquoted as "would".

I double checked using two other copies of Turing's paper. (One and two.)

There's also a problem because Deutsch uses what appears to be an italicized block quote. You'd expect the whole block quote to be a quote of Turing, but instead it's a paraphrase. Inside the paraphrase are quotation marks surrounding the misquote of Turing that I criticized.

DD's citation is also incorrect. DD cites Turing's paper to volume 442 of the Proceedings of the London Mathematical Society, but it was actually in volume 42 not 442.

To determine what's correct, we can check how Turing himself cites it. In a correction to his paper, Turing cited himself:

Proc. London Math. Soc. (2), 42 (1936-7), 230-265.

You can also get the correct cite, with volume 42, from the Stanford Encyclopedia of Philosophy or from Wikipedia.

You can also see that the latest volume of the journal, published in 2021, is volume 122. Volume 442 is unlikely to exist for over 100 more years. And the journal's website has archives showing that the Turing article was in volume 42.

Tangentially, I hope this lowers your opinion of academic peer review. DD's paper was published in Proceedings of the Royal Society of London, a prestigious and peer-reviewed journal that started in around 1830. It has published work from many famous scientists.

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Thanks to Dec for finding this misquote.

Note that DD has published a lot of misquotes.

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Update 2021-07-15: Dec pointed out that a similar Turing misquote is in DD's book The Fabric of Reality:

He [Turing] conjectured that this repertoire consisted precisely of ‘every function that would naturally be regarded as computable’.

No, Turing wrote "all numbers which could" not "every function that would".

It appears that DD got this misquote from his own paper, and also modified it. There's a recurring pattern where every time DD touches a quote, there's a significant chance that he changes something. Here, he took the word "every" which was outside of quote marks in his paper and moved it inside quote marks for his book.

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Update 2021-09-14: I contacted the academic publisher (proceedings of the royal society). They looked into the matter and said:

Apologies for the delay in getting back to you on this. A board member has had a look at the paper and does not think the misquote affects the outcome of the research presented in the paper. Although the error in the refences is unfortunate, we do not believe it will prevent readers from finding the correct article. Given the age of the paper we therefore do not think any further action is necessary.

I have several criticisms of this response.

They agree with me that DD misquoted and miscited.

Why won't they put up errata on their website? Is that too hard for them (they are bad at websites?) or do they actually not want to?

Errata serves several purposes. Academics working in the field could find out about the issue. People debating the issue could also refer to it – it would e.g. let a student whose professor repeated the error borrow the journal's authority to correct the professor. It's risky to correct your professor in general, but much easier with an official errata to point him to.

Is correcting professors a real issue? I think so because professors have been teaching Deutsch's error (there are some examples posted in the comments below). And they've been doing it out of context. In other words, even if the error did not affect the conclusion of Deutsch's paper, it still can affect other conclusions about other issues. So spreading the error matters, and it has in fact been taught in schools. Also, any reader of the paper may remember the Turing quote and use it for something else, and it may negatively affect the conclusion of their usage, even if it didn't affect the conclusion of Deutsch's paper. (Admittedly, some of the professors don't cite a source and might have been getting the error from Deutsch's book The Fabric of Reality where he repeated a similar error. But the fact that Deutsch put roughly the same error in his book is, IMO, an additional reason to errata it and at least do a little bit to stop the spread of the error.)

If they published an errata or other note about the error, they could also state their reasons for why they believe the paper's conclusion is unaffected. Other people could consider that reasoning and potentially disagree. This could be an area for critical thinking and truth seeking rather than an unaccountable authority pronouncing judgment for secret reasons. Even if it's no big deal in this case, their general attitude is concerning. How many other judgments do they make with no transparency? What is the nature of those judgments? Are any of those judgments mistaken? Do they gloss over many errors in papers they published? Could they be doing that partly out of bias and not wanting to draw attention to their own involvement in errors?

People expect academic science journals with peer review to have high standards and to be really picky about errors. They are not living up to this reputation. So much for their unlimited interest in truth for the sake of truth or whatever they were supposed to be doing.

They are still sharing the paper electronically and could update it there. Deutsch is still alive and available and could actually write or approve a small update, or they could do an update which is labelled as written by a journal editor not Deutsch.

How did this error happen? How did every step of the publishing process miss it? Did anyone intentionally cause or allow the error? Were any biases involved? They did no post mortem, no root cause analysis, no investigation into their peer review and editorial process, etc.

There are major causes for concern here. This errors calls into question how effective their reviewers and editors are. It also calls into question Deutsch's integrity. Maybe it was an accident but they have given no account of how it could have happened accidentally nor asked him to give one.

Do peer reviewers or editors not check quotes or cites? Should they? How widespread a problem is misquoting? How many other misquote reports do they receive, validate as correct criticism, and then bury? Might they be hiding a pattern revealing that many papers contain misquotes? Instead of hiding misquotes should they be doing something different like e.g. paying people enough money for misquote reports to make finding the misquotes worth the time and effort? If they actually wanted to find out about misquotes, and find out how big a problem it is, wouldn't they do something more like that? They could have responded to me by offering me money to find more misquotes since I've proven I can do it. That seems reasonable if they were better and more interesting in correcting errors.

Deutsch had an argument with a referree which was related to the text Deutsch misquoted:

http://www.daviddeutsch.org.uk/wp-content/uploads/2018/03/MathematiciansMisconception.pdf

But I soon found out that not everyone saw it that way. I also had referee problems. The referee of the paper in which I presented that proof insisted that Turing’s phrase “would naturally be regarded as computable” referred to mathematical naturalness – mathematical intuition – not nature.

(BTW, as a first impression, without reading Turing's paper or investigating the issue, I agree with the referree. When talking about naturally regarding something, that sounds like it's talking about what is natural or intuitive to people and their opinions, not about nature, due to what the key word "regard" means.)

Could Deutsch have intentionally misquoted in order to help win a specific logical point he was arguing about with the reviewer? Could the horrible, misleading presentation of the quote (as a block quote with an internal quote – which btw has tricked some people into thinking the whole thing is a quote) have been some kinda compromise worked out between Deutsch and the peer reviewer? Was the misquote in earlier drafts of the paper? Do they have records of what changes were made to the paper during peer review? In any case, there is some possible motive here for Deutsch falsifying the quote on purpose or just being biased and more careless in his own favor. Deutsch has a history of repeated misquotes throughout his career and most of them favor him in some way and I don't recall any that were bad for him, so it seems like whatever's going on involves bias if not actual deliberate, fully-conscious misquoting.

Seriously, how do wording errors in quotes happen accidentally? I understand typoing a letter or two when typing a quote in from a paper book or journal. But how do you just change the word? That seems more like Deutsch quotes stuff from memory – and his memory is biased in his favor (or there's selection bias – if he likes the version he remembers then he uses it, but if it's not ideal then he looks up the exact wording). Quoting from memory in your books and papers (and scripted speeches) is a serious scholarship violation that should lead to repercussions and major reputational damage. That's totally unacceptable. Another possibility, which there have also been potential indicators for, is that Deutsch changes quotes during his editing process without double checking the original. I suspect Deutsch thinks certain minor changes to quotes are OK, and maybe this somehow escalates to more major wording changes after multiple editing passes. Deutsch's editing could be like the game "telephone" where you whisper something to the guy next to you, who whispers it to the next guy, and so on. The goal is to repeat exactly what you heard. After something has been whispered a dozen times, often all the words are different and the meaning is totally changed.

In my experience, people are often willing to view things as "an accident" or "a mistake" without thinking about how exactly it happened. Some mistakes are simple like a one letter typo happening because you pressed the wrong keyboard key by accident because your finger dexterity is good but imperfect so occasionally you hit the wrong key (and then you usually notice and fix the typo, but not always). But many errors don't have such simple explanations and merit actual analysis. Changing the word "numbers" to "function" is not a typo due to flawed finger dexterity. That's bias, misremembering (while incorrectly believing quoting from memory is OK), intentionally falsifying the quote, or perhaps a horribly unreasonable editing processes that edits words within quotes similarly to how it edits words that are not within quotes. Or there are other possibilities like maybe a peer reviewer or editor caused the error and Deutsch didn't have full control over the final wording of his paper.

And how did the journal miss the error? Was it anyone's job to catch the error? Would the journal like to catch such errors in the future? And how did the error remain unnoticed in the archives for decades? Do they have a tiny readership? Do their readers not care about errors? Do their readers fail to report errors? Do their readers report errors but nothing is done? Would it make sense to hire people to review the archives for errors or should they focus on catching more errors before publication or should they just continue to not even post errata about errors and pretend nothing happened?

For more info, see my reply email to the journal:

https://curi.us/2477-academic-journals-are-unreasonable

I completed my 12 part video series about The Beginning of Infinity by David Deutsch. I helped him with the book for 7 years.

Parts 1-9 and 11 explain ideas from chapter 1. Part 10 is about a misquote in chapter 1. And part 12 is about my blog post about many misquotes throughout the book.

I will no longer be promoting Deutsch's books.

I made a video: Talking About David Deutsch and Andy B Harassment.

It's part of my series of posts about the multi-year severe harassment problem that David Deutsch is involved with. The harassment is the reason I closed public comments on this blog (after 18 years and over 20,000 comments).

This is adapted from a Feb 2013 email. I explain why I don't think all justificationism is infallibilist. Although I'm discussing directly with Alan, this issue came up because I'm disagreeing with David Deutsch (DD). DD claims in The Beginning of Infinity that the problem with justificationism is infallibilism:

To this day, most courses in the philosophy of knowledge teach that knowledge is some form of justified, true belief, where ‘justified’ means designated as true (or at least ‘probable’) by reference to some authoritative source or touchstone of knowledge. Thus ‘how do we know . . . ?’ is transformed into ‘by what authority do we claim . . . ?’ The latter question is a chimera that may well have wasted more philosophers’ time and effort than any other idea. It converts the quest for truth into a quest for certainty (a feeling) or for endorsement (a social status). This misconception is called justificationism.

The opposing position – namely the recognition that there are no authoritative sources of knowledge, nor any reliable means of justifying ideas as being true or probable – is called fallibilism.

DD says fallibilism is the opposing position to justificationism and that justificationists are seeking a feeling of certainty. And when I criticized this, DD defended this view in discussion emails (rather than saying that's not what he meant or revising his view). DD thinks justificationism necessarily implies infallibilism. I disagree. I believe that some justificationism isn't infallibilist. (Note that DD has a very strong "all" type claim and I have a weak "not all" type claim. If only 99% of justificationism is infallibilist, then I'm right and DD is wrong. The debate isn't about what's common or typical.)

Alan Forrester wrote:

[Justification is] impossible. Knowledge can't be proven to be true since any argument that allegedly proves this has to start with premises and rules of inference that might be wrong. In addition, any alleged foundation for knowledge would be unexplained and arbitrary, so saying that an idea is a foundation is grossly irrational.

I replied:

But "justified" does not mean "proven true".

I agree that knowledge cannot be proven true, but how is that a complete argument that justification is impossible?

And Alan replied:

You're right, it's not a complete explanation.

Justified means shown to be true or probably true. I didn't cover the "probably true" part. The case in which something is claimed to be true is explicitly covered here. Showing that a statement X is probably true either means (1) showing that "statement X is probably true" is true, or it means that (2) X is conjectured to be probably true. (1) has exactly the same problem as the original theory.

In (2) X is admitted to be a conjecture and then the issue is that this conjecture is false, as argued by David in the chapter of BoI on choices. I don't label that as a justificationist position. It is mistaken but it is not exactly the same mistake as thinking that stuff can be proved true or probably true.

In parallel, Alan had also written:

If you kid yourself that your ideas can be guaranteed true or probably true, rather than admitting that any idea you hold could be wrong, then you are fooling yourself and will spend at least some of your time engaged in an empty ritual of "justification" rather than looking for better ideas.

I replied:

The basic theme here is a criticism of infallibilism. It criticizes guarantees and failure to admit one's ideas could be wrong.

I agree with this. But I do not agree that criticizing infallibilism is a good reply to someone advocating justificationism, not infallibilism. Because they are not the same thing. And he didn't say anything glaringly and specifically infallibilist (e.g. he never denied that any idea he has could turn out to be a mistake), but he did advocate justificationism, and the argument is about justification.

And Alan replied:

Justificationism is inherently infallibilist. If you can show that some idea is true or probably true, then when you do that you can't be mistaken about it being true or probably true, and so there's no point in looking for criticism of that idea.

My reply below responds to both of these issues.

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Justificationism is not necessarily infallibilist. Justification does not mean guaranteeing ideas are true or probably true. The meaning is closer to: supporting some ideas as better than others with positive arguments.

This thing -- increasing the status of ideas in a positive way -- is what Popper calls justificationism and criticizes in Realism and the Aim of Science.

I'll give a quote from my own email from Jan 2013, which begins with a Popper quote, and then I'll continue my explanation below:

Realism and the Aim of Science, by Karl Popper, page 19:

The central problem of the philosophy of knowledge, at least since the Reformation, has been this. How can we adjudicate or evaluate the far-reaching claims of competing theories and beliefs? I shall call this our first problem. This problem has led, historically, to a second problem: How can we justify our theories or beliefs? And this second problem is, in turn, bound up with a number of other questions: What does a justification consist of? and, more especially: Is it possible to justify our theories or beliefs rationally: that is to say, by giving reasons -- 'positive reasons' (as I shall call them), such as an appeal to observation; reasons, that is, for holding them to be true, or at least 'probable' (in the sense of the probability calculus)? Clearly there is an unstated, and apparently innocuous, assumption which sponsors the transition from the first to the second question: namely, that one adjudicates among competing claims by determining which of them can be justified by positive reasons, and which cannot.

Now Bartley suggests that my approach solves the first problem, yet in doing so changes its structure completely. For I reject the second problem as irrelevant, and the usual answers to it as incorrect. And I also reject as incorrect the assumption that leads from the first to the second problem. I assert (differing, Bartley contends, from all previous rationalists except perhaps those who were driven into scepticism) that we cannot give any positive justification or any positive reason for our theories and our beliefs. That is to say, we cannot give any positive reasons for holding our theories to be true. Moreover, I assert that the belief we can give such reasons, and should seek for them is itself neither a rational nor a true belief, but one that can be shown to be without merit.

(I was just about to write the word 'baseless' where I have written 'without merit'. This provides a good example of just how much our language is influenced by the unconscious assumptions that are attacked within my own approach. It is assumed, without criticism, that only a view that lacks merit must be baseless -- without basis, in the sense of being unfounded, or unjustified, or unsupported. Whereas, on my view, all views -- good and bad -- are in this important sense baseless, unfounded, unjustified, unsupported.)

In so far as my approach involves all this, my solution of the central problem of justification -- as it has always been understood -- is as unambiguously negative as that of any irrationalist or sceptic.

If you want to understand this well, I suggest reading the whole chapter in the book. Please don't think this quote tells all.

Some takeaways:

• Justificationism has to do with positive reasons.

• Positive reasons and justification are a mistake. Popper rejects them.

• The right approach to epistemology is negative, critical. With no compromises.

• Lots of language is justificationist. It's easy to make such mistakes. What's important is to look
  out for mistakes and try to correct them. ("Solid", as DD recently used, was a similar mistake.)

• Popper writes with too much fancy punctuation which makes it harder to read.

A key part of the issue is the problem situation:

How can we adjudicate or evaluate the far-reaching claims of competing theories and beliefs?

Justificationism is an answer to this problem. It answers: the theories and beliefs with more justification are better. Adjudicate in their favor.

This is not an inherently infallibilist answer. One could believe that his conception of which theories have how much justification is fallible, and still give this answer. One could believe that his adjudications are final, or one could believe that his adjudications could be overturned when new justifications are discovered. Infallibilism is not excluded nor required.

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Looking at the big picture, there is the critical approach to evaluating ideas and the justificationist or "positive" approach.

In the Popperian critical approach, we use criticism to reject ideas. Criticism is the method of sorting out good and bad ideas. (Note that because this is the only approach that actually works, everyone does it whenever they think successfully, whether they realize it or not. It isn't optional.) The ideas which survive criticism are the winners.

In the justificationist approach, rather than refuting ideas with negative criticism, we build them up with positive arguments. Ideas are supported with supporting evidence and arguments. The ones we're able to support the most are the winners. (Note: this doesn't work, no successful thinking works this way.)

These two rival approaches are very different and very important. It's important to differentiate between them and to have words for them. This is why Popper named the justificationist approach, which had gone without a name because everyone took it for granted and didn't realize it had any rival or alternative approaches.

Both approaches are compatible with both infallibilism and fallibilism. They are metaphorically orthogonal to the issue of fallibility. In other words, fallibilism and justificationism are separate issues.

Fallibilism is about whether or not our evaluations of ideas should be subjected to revision and re-checking, or whether anything can be established with finality so that we no longer have to consider arguments on the topic, whether they be critical or justifying arguments.

All four combinations are possible:

Infallible critical approach: you believe that once socialist criticisms convince you capitalism is false, no new arguments could ever overturn that.

Infallible justificationist approach: you believe that once socialist arguments establish the greatness of socialism, then no new arguments could ever overturn that.

Fallible critical approach: you believe that although you currently consider socialist criticisms of capitalism compelling, new arguments could change your mind.

Fallible justificationist approach: you believe that although you currently consider socialist justifying arguments compelling (at establishing the greatness and high status of the socialism, and therefore its superiority to less justified rivals), you are open to the possibility that there is a better system which could be argued for even more strongly and justified even more and better than socialism.

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BTW, there are some complicating factors.

Although there is an inherent asymmetry between positive and negative arguments (justifying and critical arguments), many arguments can be converted from one type to the other while retaining some of the knowledge.

For example, someone might argue that the single particle two slit experiment supports (justifies) the many-worlds interpretation of quantum physics. This can be converted into criticisms of rivals which are incompatible with the experiment. (You can convert the other way too, but the critical version is better.)

Another complicating factor is that justificationists typically do allow negative arguments. But they use them differently. They think negative arguments lower status. So you might have two strong positive arguments for an idea, but also one mild negative argument against it. This idea would then be evaluated as a little worse than a rival idea with two strong positive arguments but no negative arguments against it. But the idea with two strong positive arguments and one weak criticism would be evaluated above an idea with one weak positive argument and no criticism.

This is easier to express in numbers, but usually isn't. E.g. one argument might add 100 justification and another adds 50, and then a minor criticism subtracts 10 and a more serious criticism subtracts 50, for a final score of 90. Instead, people say things like "strong argument" and "weak argument" and it's ambiguous how many weak arguments add up to the same positive value as a strong argument.

In justification, arguments need strengths. Why? Because simply counting up how many arguments each idea has for it (and possibly subtracting the number of criticisms) is too open to abuse by using lots of unimportant arguments to get a high count. So arguments must be weighted by their importance.

If you try to avoid this entirely, then justificationism stops functioning as a solution to the problem of evaluating competing ideas. You would have many competing ideas, each with one or more argument on their side, and no way to adjudicate. To use justificationism, you have to have a way of deciding which ideas have more justificationism.

The critical approach, properly conceived, works differently than that. Arguments do not have strengths or weights, and nor do we count them up. How can that be? How can we adjudicate between competing ideas with out that? Because one criticism is decisive. What we seek are ideas we don't have any criticisms of. Those receive a good evaluation. Ideas we do have criticisms of receive a bad evaluation. (These evaluations are open to revision as we learn new things.) (Also there are only two possible evaluations in this system. The ideas we do have criticisms of, and the ideas we don't. If you don't do it that way, and you follow the logic of your approach consistently, you end up with all the problems of justificationism. Unless perhaps you have a new third approach.)

I took down the website beginningofinfinity.com and replaced it with the below protest message.

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This website promoted David Deutsch’s book The Beginning of Infinity (BoI). David was my friend, mentor and colleague. I helped with drafts of BoI for seven years (I wrote over 200 pages of suggestions, comments and edits to help with the book). At David’s request, I made and owned this BoI website and the BoI Google Groups forum.

I’ve taken this site down in protest due to David’s role in harassment against me. I’ve been harassed by his fans and he lied about me. They’ve disrupted my blog, forums, and ability to discuss with other intellectuals online.

I also discovered many misquotes in BoI which, alone, would be enough reason for me to stop actively promoting BoI.

The story in short: David (and his Taking Children Seriously co-founder Sarah) created an online community which I was part of, but then he left after 15 years. Now he has a second fan community, which is harassing the first community. The harassment is primarily targeted at me, presumably because I’m now the leader of the older community. One of the motives some people have communicated is that they see me as David’s enemy.

The harassment has persisted for years, and has included dozens of fake identities (some maintained for months), hundreds of harassing messages from over one hundred IP addresses, stalking me to other websites to disrupt my conversations there, DDoSing, impersonation, threats, spam, plagiarism, libel, fraud and doxxing. Some of that is illegal (I am not a lawyer; I’ve presented evidence; judge for yourself).

David has been unwilling to ask his fans to stop, to discuss the matter privately or publicly, to explain himself, to dispute any of the evidence, to state a grievance he has against me, or to offer any terms for truce. I’d be willing to do conflict resolution through proxies or associates (David’s, mine or both) but he’s been unwilling to do that.

When asked to tell his fans to stop harassing, David not only refused, but turned it around and lied to attack the victim (me) which justified and encouraged additional harassment. His lie is damaging to my reputation and it seems likely that he’s said it to other people privately. Rather than deescalate, he choose to openly join in the harassment himself by smearing me. He hasn’t retracted his lie, nor has he denied circulating it privately so that harassers believed it and were motivated by it. This is despite me posting documentation that he’s lying. (I understand David’s lie to be libel and defamation, but I don’t have the resources to stop it. I am not a lawyer and you can read what he said at the link, along with the actual facts, and judge for yourself.)

I finally gave up and closed the comments on my blog – after 18 years and over 20,000 comments – due to being unable to deal with the harassment there. I’ve also been harassed at Reddit, Less Wrong, Twitter, Facebook, Google Groups, Basecamp, Discord and Slack. They won’t leave me alone.

David hasn’t argued that he isn’t involved or explained why his actions are OK. He hasn’t said which facts or claims he accepts or denies, presented his own account of events, or argued that my account is false. He hasn’t denied gossiping negatively about me, nor said what he’s doing to avoid crossing the line into unacceptable behavior. He hasn’t given an innocent explanation for the links between the harassment and his social circle.

David hasn’t taken steps to distance himself from the problem or to reduce the harm being done. He hasn’t stated that he’s opposed to harassment in general or to any of the harassing actions by his fans against me. He hasn’t blocked the worst harasser on Twitter, and keeps tweeting with him. David won’t do anything to delegitimize the harassment. Many of David’s friends and associates behave similarly or worse. David won’t even pay lip service to saying that I’m not his enemy or that I shouldn’t be harassed.

David also hasn’t disowned the subreddit for The Beginning of Infinity, which was created by the worst harasser. Nor has David disowned a nasty message posted under the name “David Deutsch” (I believe it was impersonation, which is something that ought to concern David). I think some of David’s fans have taken his behavior as a signal that he wants me harassed, and he’s refused to deny wanting me harassed.

I’ve documented the harassment, provided extensive evidence, and explained what’s going on. The response has been a mix of silence and more harassment. David is more powerful and influential than me, and has more support and resources, so there isn’t much I can do besides speak truth to power and hope that reasonable people listen. I’ve tried to put up with things, ignore things for months, privately ask for a peaceful resolution, publicly ask for a peaceful resolution, etc. In the past, David spent thousands of hours discussing with me, but now he’s stonewalling all attempts at deescalation.

I have the right to be left alone, not harassed for years. My rights are being violated, and I think David is the root cause of the problem. David needs to take appropriate steps to reign in his toxic community, and needs to retract his lie about me.

If you’d like to help, please ask David and his community about the problem, criticize them and complain, but don’t harass them in return. Maybe David will stop his bad behavior if people complain. David’s public email address is [email protected] and his Twitter is @DavidDeutschOxf.

For more information, read my articles about the harassment. To contact me, email [email protected].

— Elliot Temple (my philosophy work)

I thought that even though David Deutsch (DD) and his fans were harassing me, his books were still good. But I hadn’t reread them for years. On review, The Beginning of Infinity contains lots of misquotes. DD’s books are a lot worse than I realized. I was horrified to discover how frequently and severely DD misquotes. I trusted DD’s ability to quote accurately and handle details reliably and correctly, but I was wrong.

Also, DD explains too little in his books. They’re too hard to learn effectively from because he doesn’t give enough depth or detail. I had trouble seeing this in the past because I had many conversations with DD which filled in the gaps for me. But even when DD’s books say something important, he often doesn’t provide enough information for a reasonable, smart person to understand it well.

DD’s books have some good parts mixed in, but, due to the serious flaws, I retract my recommendation of them. I no longer want to actively promote them.

I’m sorry. I should have caught the misquotes earlier. I was capable of finding those errors years ago. I found and wrote about other similar errors.

I was giving DD space after he left the community. I guessed (I think accurately) that he wanted to be left alone by me and I was trying to respect his wishes. I mostly stayed away from him and his work after he left. I thought continuing to recommend his books was safe, but I was wrong about that.

I only started my video series about BoI after I gave up on DD leaving me alone. I caught the Feynman misquote in chapter 1 when I first reread it for the videos. BoI misquotes Feynman:

As the physicist Richard Feynman said, ‘Science is what we have learned about how to keep from fooling ourselves.’

Then, due to the harassment, I was reviewing old information and found a Popper misquote on an old TCS webpage. Someone (“Dec”) saw my post and told me that the same Popper quote was in BoI too. That made two misquotes in BoI, which was a possible pattern. That led to checking more quotes, which led to discovering that there are tons of misquotes in BoI.

It seems that no other readers of BoI have noticed the misquoting problem yet (the errata page has factual errors but no misquotes), which I think is important information about the world. Regardless, I should have done better.

Read about the misquotes.

This is part of a series of posts explaining the ongoing harassment against me from David Deutsch and his associates and fans.

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David Deutsch (DD) was never as good as I thought. But he had some great ideas, particularly re physics (as far as I know) and Critical Rationalism (CR). He read Popper and understood a lot – while others fail to understand much Popper. He also understood Dawkins and connected CR with neo-Darwinism, and he understood stuff about computation and information theory. The four strands in The Fabric of Reality (FoR) are good, valuable, etc., though DD overemphasized them. They are just four strands out of over ten, not the top four. Math, logic, (classical) liberalism, (Austrian) economics, moral knowledge (including from Objectivism, Judaism and Christianity), and Theory of Constraints are examples of other major, important, deep areas of human knowledge. DD was overly narrow when I knew him, and wouldn’t reread Rand or Szasz (he knew stuff about their ideas, but also had forgotten or never known a lot of it), and would never learn Mises or Burke for the first time (he knew some Hayek, who was Mises’ student, but Mises was much better). One of the issues is that DD reads fewer books than people think he does. I had to repeatedly recommend some Feynman books to get him to read those (he’d read some long ago, but never read others), and I was unable to get him to read much else.

Aside about DD’s lack of reading: In 2012, DD blatantly contradicted Szasz. I’d read over a dozen Szasz books recently, and I’d discussed them with Szasz himself. Nevertheless, DD didn’t believe me about what Szasz’s view are, and didn’t want to reread Szasz as I urged him to. But DD was confident enough to challenge me (my italics): “If you quote a statement or short passage of mine in this thread, and a statement or short passage of Szasz's that contradicts it, I promise to re-read the whole book in which Szasz's statement or passage appears.” I provided quotes. One of the issues was that DD was unaware of Szasz’s opposition to the medicalization of everyday life, even though Szasz titled a book about this issue. DD thought it’d be “harmless” to call effective anti-Islamism arguments a “cure” or “treatment for Islamism”. After I gave quotes, DD acknowledged that he “wasn't aware that Szasz totally rejects the use of the term 'treatment' in the way I used it, i.e. to describe what psychiatrists do.”, bought the book on Kindle (so he got it immediately), and said he’d read it. But he never actually read it and followed up. This incident disturbed me because it was a clear example of DD lacking integrity. He made a “promise” then broke it.

FoR and The Beginning of Infinity (BoI) are primarily about CR. They build on CR some and connect CR to other areas. Not many people understood enough Popper to start working out implications of CR, and DD succeeded at that and also learned some other important stuff that he could connect CR to. That’s impressive and was a contribution to human knowledge.

I recently discovered that BoI has lots of misquotes. DD is a worse scholar, with less integrity, than I thought.

DD has other notable ideas outside of physics, too. Taking Children Seriously (TCS) has important insight mixed in, but is also too disorganized and has major errors. DD’s static meme idea is good (I don’t think it’s perfect or complete, but it’s a good lead/start/try). He got a lot right about politics and economics, such as advocating capitalism, but he didn’t contribute much there. DD’s idea about the jump to universality is a good start on something important, as is his criticism of weighing explanations. DD’s anti-weighing ideas are some of the inspiration for my Yes or No Philosophy.

Original thinkers take risks. They may be wrong some. DD’s attacks on age of consent laws were a mistake. His attack on monogamy had some reasonable points but overall I’d say that was a bad idea that needed to be thought through more. DD doesn’t understand or respect tradition and traditional knowledge enough, but he was willing to make bold claims, some of which were good. It’s a lot better to say something important and also three wrong ideas than to say nothing risky or important.

DD was personally irrational about tidiness, scheduling, food, children and more. And he accepted a bunch of irrationalities as unsolvable problems and didn’t try to fix them.

DD’s extremely biased about ageism. He sees some ageism that most people don’t, but he also sees ageism when it isn’t there. For example, DD once argued to me (in 2004) that a news article mentioning metaphorically taking a politician behind the woodshed shows that violence against children is part of the fabric of our culture. DD claimed people wouldn’t say such awful things in general, and are only willing to do it due to ageism. I said people still talk about hanging, which isn’t due to ageism, it’s just because society does use violent words. (There’s a children’s word game named “hangman” which is used in classrooms.) DD was so biased that he responded: “[The word] Hang doesn't have a connotation of baseness and horror.”. He denied the badness of hanging because it isn’t anti-children and he wanted to claim anti-child stuff is much worse. Hanging kills people, which makes it more base and horrific than beating someone behind a woodshed. Also hanging is public violence, while behind a woodshed means privately (second source).

DD’s arrogant and stopped learning much before I met him in 2001. He’s dishonest with others on purpose, including his friends, for a variety of reasons including conflict avoidance and social climbing. He’s really scared of the world and of conflict with people, and he tries to hide problems (contrary to his philosophical theories about problem solving).

He’s a social climber who cares deeply about his reputation. I’m not sure how much he always was. I think maybe he was less concerned about it when he started TCS, and may have been changed by the negative experience of TCS’s failure to catch on and the hateful reactions it got. He may also have gotten more scared after a negative incident with the government around 2003 (but he kept advising other people not to be scared of the government, and some of that advice was horribly unrealistic and irresponsible, and could have gotten people’s children taken away).

DD’s a two-faced person and extremely biased about Lulie Tanett (LT). He put a lot of work into telling me to be friends/colleagues with LT, and telling LT to be friends/colleagues with me, but he also went behind my back and sabotaged our interactions sometimes. He said negative stuff about me to her while hiding what he was doing from me. One time, he put a lot of work into convincing her that I was threatening her when I told her some conditions she’d have to meet to remain a member of a small, private discussion group I owned (the conditions were basically just being an active poster). DD basically told her that learning from me was her best chance fixing her problems and becoming a rational, productive intellectual, so alienating her from me like that was really bad, though he did much worse later.

After leaving my community, he heavily pressured her to drop me entirely, and finally after around five years of pressure she dropped me. Doing that after convincing her I was crucial to her learning – and after she was very attached to me – was really horrible of him. It’s a little like a coercive parent controlling who their kid is allowed to be friends with. But it’s much worse to belatedly take away a friendship from your kid, over 10 years after it started, that you recommended and convinced them was crucial to their career.

DD really messed with LT’s head and her lack of accomplishments and inability to do productive work or learn much philosophy is significantly his fault. It’s also Sarah Fitz-Claridge’s (SFC) fault and TCS’s fault. SFC publicly posted on 2006-03-31 on TCS list that LT is her daughter, though they all seem to be trying to hide it now. Most people don’t realize that when DD promotes LT, that’s basically nepotism. DD has known LT since she was around age 2, and SFC moved her family to live near DD in Oxford when LT was around 7. DD treats LT partially like a daughter. However, he won’t take responsibility for actually trying to treat her in a TCS parenting way because that’d be too much work for him. In general, DD likes to keep things flexible and avoid having clear responsibilities, even with his closest associates. (E.g. he said that he avoids having anything scheduled at a specific time because having something coming up today or tomorrow often prevents him from working.) He mostly avoided explicit obligations with me, too, though he made exceptions like saying he’d write a forward for my book, saying he’d write a TCS book, and, as I discussed above, promising to read a Szasz book.

TCS parenting worked out badly for LT. TCS, SFC and DD did poorly in practice, but they’re dishonest with the public about TCS’s practical results.

SFC’s post saying LT is her daughter was an announcement of an official TCS event at SFC’s home in the UK. The event involved me, SFC and LT giving speeches about TCS, plus Q&A. The post also said LT “will be taking over the management of the TCS web site”, but then SFC violated TCS principles by breaking her word to her own daughter (LT wanted the TCS website, but SFC refused to hand it over while leaving it inactive – it’s been inactive for 15 years now). After the TCS event, SFC told me and LT that she despised the TCS parents who attended, had met them before, and thought they were hopeless and would never make progress on their problems. She hid her negativity while they were present. SFC also broke her word about letting LT and I have the money we charged for the event, and, after the event was over, she decided instead to simply take a share for herself without discussing the matter. She either took half or a third (I don’t remember). It wasn’t a lot of money and didn’t matter much to me, but I was disturbed that she’d break her word and take money away from her child who had very little money. And it’s ironic to screw over your child for money from a TCS seminar which talked about treating children well.

DD met another mother of young children before SFC, but stopped associating with that family because he didn’t think the mother was a good enough parent. Specifically, he found out that the mother had told the kids to be on their best behavior when visiting DD, so he ended things with them. But SFC was an awful parent and DD put up with it. I’m told she routinely closed her office door while her toddlers fought outside. I don’t know why DD got rid of the first mother but then put up with SFC’s bad parenting. (Source: I’ve been told things by people who were part of the TCS community before me and who knew SFC/LT/DD/etc in person.)

SFC also mistreated DD himself, and he put up with that too, though I observed that after he was already highly invested in TCS, SFC, LT and LT’s sibling. When I visited the UK for three weeks, DD gave me a draft chapter of BoI to read and discuss. SFC was jealous that she didn’t get one. She kept bugging him about it repeatedly and trying to pressure him into giving her one (he refused). She was a bad friend who didn’t respect his control over his writing process.

I found out a lot about DD being two-faced with me because LT told me lots of the private stuff DD said to her (without getting his permission or telling him that she shared it). I don’t think she was wrong to do that, btw. DD was like a father to her (actively involved in her life since she was a toddler) and somewhat of a father-figure to me. It’s reasonable and understandable for kids to share information and discuss strategies for dealing with the irrationalities of their parents. On the other hand, I also think LT learned to be a two-faced gossip from DD and SFC, and there’s a major problem there. She sometimes shared info about me and others with people she didn’t know well (she confessed to doing this). Similarly, DD started badmouthing public figures (particularly ones he’d personally interacted with) to me when he hadn’t known me very long yet, and he kept doing it despite me frequently just literally not responding at all to it. Imagine how much mean gossip he’d tell someone who actually encouraged it…

DD wanted a student. He liked me when he gave partial explanations that almost no one could learn from, and I figured stuff out (often more than he meant or knew). That worked well when his conclusions were correct. But I couldn’t usually come up with convincing reasons for DD’s claims when he was wrong. Over time, I learned most of the stuff he was right about and that put more emphasis on the issues where we disagreed, since there was less other stuff left for him to teach me about. DD was never rational about debate and truth-seeking. I’m not sure that he ever changed his mind about anything major due to my arguments, despite thousands of hours of discussions. I did successfully correct him on many smaller things, including in the seven years I commented on and edited drafts of BoI, but he didn’t post mortem those errors to look for larger errors that could be root causes.

Anyway, DD helped me understand a lot of his ideas. Some were great and some were errors. Overall, engaging with him and his ideas was very intellectually beneficial for me. I wouldn’t regret it just because he left me. But I really do wish he’d leave me alone now. Hating me for no clear reason, and having his fans harass me, is really nasty. I didn’t recognize how irrational and dangerous he was. I don’t know major things that I should done have differently with DD, even in hindsight, though.

I’ve discovered that David Deutsch (DD) is an unreliable quoter. His book The Beginning of Infinity (BoI) contains many serious quotation errors, and he has misquoted elsewhere too.

For context, DD and I were close associates for a decade. I helped with BoI for 7 years and wrote over 200 pages of comments, suggestions and edits on drafts of the book. I learned a lot from him but I trusted his scholarship too much. I promoted his books. I was wrong about him and his books in multiple ways. My mistake. I retract my previous endorsements and recommendations of DD’s books. That doesn’t mean the books are awful or shouldn’t be read, but I no longer want to promote them myself. There are good ideas mixed in, but be wary of major problems.

Misquotes in The Beginning of Infinity

Block quotes are from BoI unless otherwise stated.

I think there will certainly not be novelty, say for a thousand years. This thing cannot keep going on so that we are always going to discover more and more new laws. If we do, it will become boring that there are so many levels one underneath the other . . . We are very lucky to live in an age in which we are still making discoveries. It is like the discovery of America – you only discover it once.
The Character of Physical Law (1965)

That’s different than what Feynman wrote. DD changed the words “perpetual novelty” to “novelty”. DD also changed “keep on going” to “keep going on”. (More details.)

Behind it all is surely an idea so simple, so beautiful, that when we grasp it – in a decade, a century, or a millennium – we will all say to each other, how could it have been otherwise?
John Archibald Wheeler, Annals of the New York Academy of Sciences, 480 (1986)

What Wheeler actually wrote was "Behind it all is surely an idea so simple, so beautiful, so compelling that when–in a decade, a century, or a millennium–we grasp it, we will all say to each other, how could it have been otherwise?”. DD deleted “so compelling” and moved “we grasp it” to before the dashed part. (More details.)

As the physicist Richard Feynman said, ‘Science is what we have learned about how to keep from fooling ourselves.’

Feynman didn’t say that. It’s not even a documented quote with some changes. It seems made up with no original source or evidence.

I checked the web and some Feynman books and speeches. It’s likely that the misquote started in 2000 in the article Magical Thinking (my thanks to Justin Mallone for finding that article), which paraphrased Feynman that way without using quote marks or giving a source. Unfortunately, the wording made it sound like it was an actual quote, so I think people started spreading it as a quote. Then DD probably got the misquote from an unreliable webpage and put it in his book without trying to find a primary source or telling his readers which unreliable secondary source he used. There are now two books which give this quote and cite it to as quoted in BoI. There’s also a book which gives the quote with a footnote saying that the author was unable to find a source for the quote (then don’t put it in your book!).

Feynman said some similar ideas in Cargo Cult Science, but the wordings are different. DD didn’t take the quote from there and add one or two errors (like he did with some other quotes, where you can tell that he’s quoting a specific thing incorrectly). It’s too different to have come from that speech.

Popper wrote:

The inductivist or Lamarckian approach operates with the idea of instruction from without, or from the environment. But the critical or Darwinian approach only allows instruction from within – from within the structure itself . . .

I contend that there is no such thing as instruction from without the structure. We do not discover new facts or new effects by copying them, or by inferring them inductively from observation, or by any other method of instruction by the environment. We use, rather, the method of trial and the elimination of error. As Ernst Gombrich says, ‘making comes before matching’: the active production of a new trial structure comes before its exposure to eliminating tests.
The Myth of the Framework

DD ends the first sentence of the second paragraph with “without the structure” and then a period. Instead of a period, Popper had a comma there and continued the sentence. Then, the rest of that paragraph that DD quotes is actually from a different section of the book. DD combined sentences from different places in the book and presented them as one paragraph with no ellipsis or square brackets to indicate a modification.

And DD left out the words “In fact,” before “I contend”. DD also put an ellipsis at the end of the first paragraph when that should be a period. There are no omitted words there. The paragraph ends there and DD continues without skipping a paragraph. DD also left out Popper’s italics.

A similar misquote also appeared on the Taking Children Seriously (TCS) website (mirror). DD co-founded TCS with Sarah Fitz-Claridge and she’s my best guess at the author of that misquote, though it could have been DD. Either way, he has responsibility for what it says on the official website of the movement he co-founded (particularly for pages, like this one, with no author specified).

Judging by the similarities, the misquote in BoI was likely based on the TCS website misquote. Even when a secondary source is accurate, it’s problematic to take a secondary source quote and then edit it without checking the original. When you do that, you’re making edits without knowing the original context and wording, so you aren’t in a good enough position to judge what edits are OK.

(More details about the TCS website version of the misquote.)

Thanks to Dec for telling me that this misquote is also in BoI after I wrote about the version from the TCS website.

As the physicist Stephen Hawking put it, humans are ‘just a chemical scum on the surface of a typical planet that’s in orbit round a typical star on the outskirts of a typical galaxy’.

This quote seems to be made up based on a similar Hawking quote about “chemical scum” from the 1995 TV program (Reality on the Rocks: Beyond Our Ken by Ken Campbell (IMBD, trailer)). Interestingly, DD had quoted it correctly in The Fabric of Reality as “The human race is just a chemical scum on a moderate-sized planet, orbiting round a very average star in the outer suburb of one among a hundred billion galaxies.” I didn’t find the original video, but it’s quoted that way in various places online that aren’t based on DD’s writing. (Some sources have “around” instead of “round”, which is an understandable difference given how similar those words can sound when spoken out loud.)

It seems that DD made up this misquote for his 2005 TED talk and then based the quote in BoI on his talk. Alan Forrester checked the books The large scale structure of space-time, A Brief History of Time, The Grand Design, The Nature of Space and Time and The Universe in a Nutshell, but found that none contain the word “scum”. And I can’t find any online sources for Hawking ever saying the BoI version of the quote (whereas with the The Fabric of Reality version, I easily found other online sources).

This misquote doesn’t seem fully accidental. DD changed the quote to be more elegant and catchy by repeating “typical” three times. I’ve noticed that many of DD’s misquotes involve changing text to sound nicer.

(More details.)

[Horgan believed] that science has the ability to ‘resolve questions’ objectively […]

Horgan actually wrote “Scientists have the ability to pose questions and resolve them in a way that critics, philosophers, historians cannot.” DD changed Horgan’s words “resolve them” to “resolve questions”, which is wrong without using square brackets to indicate an edit. (More details.)

The issue of what exactly needs to be explained in an ‘appearance of design’ was first addressed by the clergyman William Paley, the finest exponent of the argument from design. In 1802, before Darwin was born, he published the following thought experiment in his book Natural Theology.

It’s unclear what, if anything, “appearance of design” is a quote from, but it’d be understandable if a reader believed it was a quote of Paley in Natural Theology. But it’s not in that book.

[Paley wrote:]

The inference we think is inevitable, that the watch must have had a maker . . . There cannot be design without a designer; contrivance without a contriver; order without choice; arrangement without anything capable of arranging; subserviency and relation to a purpose without that which could intend a purpose; means suitable to an end . . . without the end ever having been contemplated or the means accommodated to it. Arrangement, disposition of parts, subserviency of means to an end, relation of instruments to a use imply the presence of intelligence and mind.

DD changed the words “any thing” to the word “anything” and changed “an use” to “a use”. DD also quoted from both chapters 1 and 2, but presented it as single paragraph with ellipses. DD also removed a comma near the end before “imply the presence of intelligence and mind” which helped the reader understand the text. (DD edited other punctuation too, but this punctuation edit stood out to me because it’s significantly worse than the original.) (More details.)

As Hawking once put it, ‘Television sets could come out [of a naked singularity].’

Thanks to Alan Forrester for looking into this quote at my request. He was unable to find Hawking saying this. He searched the web and the following books: The large scale structure of space-time, A Brief History of Time, The Grand Design, The Nature of Space and Time and The Universe in a Nutshell.

As Hofstadter remarked, ‘In retrospect, I am quite amazed at how much genuine intelligence I was willing to accept as somehow having been implanted in the program . . . It is clear that I was willing to accept a huge amount of fluidity as achievable in this day and age simply by putting together a large bag of isolated tricks, kludges and hacks.’

Hofstadter’s actual paragraph ends with “a large bag of isolated tricks-kludges and hacks, as they say.” DD’s punctation edits changed the meaning. Hofstadter said “isolated tricks” and then gave “kludges and hacks” as a rewording of “isolated tricks”. DD changed it to a list of three things, “tricks, kludges and hacks” and made it sound like the modifier “isolated” applies to all three, whereas in the original it applied only to “tricks”. As a list, it means that all three things were put together. In the original, it says they put together tricks, and then provides the additional information that the tricks could be characterized as kludges and hacks as people (informally) say.

Thanks to Dec for bringing up this misquote.

Representative Roger Q. Mills of Texas complained in 1882, ‘I thought . . . that mathematics was a divine science. I thought that mathematics was the only science that spoke to inspiration and was infallible in its utterances [but] here is a new system of mathematics that demonstrates the truth to be false.’

This text is available in the Congressional Record. DD changed the words "by inspiration" to "to inspiration". It’s also misleading that where DD wrote “[but]”, with no ellipsis, he skipped multiple sentences and continued with text from a different paragraph.

DD likely copied this misquote from Fair Representation without telling his readers that he was trusting a secondary source without fact checking it, and without letting readers know which secondary source he was using.

Thanks to Justin Mallone for looking this up at my request.

Before Blackmore and others realized the significance of memes in human evolution, all sorts of root causes had been suggested [...] [T]here is the ‘Machiavellian hypothesis’ that human intelligence evolved in order to predict the behaviour of others, and to fool them. […] Blackmore’s ‘meme machine’ idea, that human brains evolved in order to replicate memes, must be true.

At first I read “Machiavellian hypothesis” as a quote of Blackmore from her book The Meme Machine that DD mentioned earlier and included in his bibliography. If so, it's a misquote. That phrase isn’t in her book.

But maybe “Machiavellian hypothesis” is merely meant to be the name of a hypothesis. If so, it’s the wrong name. The correct name is "Machiavellian Intelligence”, as one can find out from Blackmore’s book or Wikipedia. Blackmore has an index entry for “Machiavellian Intelligence” and cites two books with “Machiavellian Intelligence” in their title. She also writes “An influential version of social theory is the ‘Machiavellian Intelligence’ hypothesis (Byrne and Whiten 1988; Whiten and Byrne 1997).”. It appears that DD read her book, misremembered the name of the hypothesis, didn’t check it, and put quote marks around it. (More details.)

The more important fundamental laws and facts of physical science have all been discovered, and these are now so firmly established that the possibility of their ever being supplanted in consequence of new discoveries is exceedingly remote . . . Our future discoveries must be looked for in the sixth place of decimals.
Albert Michelson, address at the opening of the Ryerson Physical Laboratory, University of Chicago, 1894

The source for this, which DD didn’t specify, is the book Light Waves and Their Uses (1903) by Albert Michelson. The speaker wrote down what he said in his own book. Michelson wrote:

Many other instances might be cited, but these will suffice to justify the statement that "our future discoveries must be looked for in the sixth place of decimals."

DD incorrectly quoted this as Michelson saying “[o]ur future discoveries must be looked for in the sixth place of decimals” himself, when Michelson actually had it in quote marks and talked about that statement. Deleting quote marks within a quote is misquoting. (More details.)

For example, as I wrote in The Fabric of Reality:

Consider one particular copper atom at the tip of the nose of the statue of Sir Winston Churchill that stands in Parliament Square in London. Let me try to explain why that copper atom is there. It is because Churchill served as prime minister in the House of Commons nearby; and because his ideas and leadership contributed to the Allied victory in the Second World War; and because it is customary to honour such people by putting up statues of them; and because bronze, a traditional material for such statues, contains copper, and so on. Thus we explain a low-level physical observation – the presence of a copper atom at a particular location – through extremely high-level theories about emergent phenomena such as ideas, leadership, war and tradition.

There is no reason why there should exist, even in principle, any lower-level explanation of the presence of that copper atom than the one I have just given. Presumably a reductive ‘theory of everything’ would in principle make a low-level prediction of the probability that such a statue will exist, given the condition of (say) the solar system at some earlier date. It would also in principle describe how the statue probably got there. But such descriptions and predictions (wildly infeasible, of course) would explain nothing. They would merely describe the trajectory that each copper atom followed from the copper mine, through the smelter and the sculptor’s studio and so on . . . In fact such a prediction would have to refer to atoms all over the planet, engaged in the complex motion we call the Second World War, among other things. But even if you had the superhuman capacity to follow such lengthy predictions of the copper atom’s being there, you would still not be able to say ‘Ah yes, now I understand why they are there’. [You] would have to inquire into what it was about that configuration of atoms, and those trajectories, that gave them the propensity to deposit a copper atom at this location. Pursuing that inquiry would be a creative task, as discovering new explanations always is. You would have to discover that certain atomic configurations support emergent phenomena such as leadership and war, which are related to one another by high-level explanatory theories. Only when you knew those theories could you understand why that copper atom is where it is.

In addition to checking this using ebooks, I also compared hardback copies of both books. It’s FoR pp. 22-23 and BoI pp. 109-110.

DD quotes “understand why they are there” but the original reads “understand why it is there”. DD changed the words “it is” to “they are”.

DD quotes "Pursuing that inquiry”, but FoR says “this inquiry”. DD changed the word “this” to “that”.

DD quotes “understand why that copper atom is where it is”. DD omitted the word “fully”. The original said “understand fully why”.

DD wrote “[You]” in BoI, which is an incorrect use of square brackets. He skipped two sentences and should have used an ellipsis. And it says “You” in the original, so he shouldn’t put it in square brackets since it isn’t modified. Square brackets can only replace an ellipsis when the text in square brackets replaces/summarizes/paraphrases all the skipped text, but the word “You” doesn’t replace the skipped sentences.

The italics “why” and “what it was” are not italicized in FoR.

The ellipsis DD used in “studio and so on . . . In fact” is incorrect because the original had a period after “so on”. There should be four dots there (one for the period, and three for the ellipsis), not three dots.

DD doesn’t even quote himself accurately.

Other Misquotes

In The Fabric of Reality, DD wrote:

Mystery is part of the very concept of time that we grow up with. St Augustine, for example, said:

What then is time? If no one asks me, I know; if I wish to explain it to one who asks, I know not. (Confessions)

This quote has some word changes compared to the edition of Confessions that I checked. However, there are other English translations, so it could be an accurate quote of one of those. DD didn’t say which translation he used, which is more problematic than usual when quoting a particular translation rather than quoting something with a single, unambiguous wording that could be looked up.

DD wrote in Not Merely the Finest TV Documentary Series Ever Made:

As Karl Popper put it, we humans can “let our ideas die in our place.”

I found Popper saying something similar three times, but he didn’t use that wording. I think DD relies on his memory for this quote, instead of checking a source. He’s quoted it different ways in different places (e.g. with “theories” instead of “ideas” in Why It’s Good To Be Wrong and BoI). DD should get quotes from sources instead of putting quote marks around what he believes he remembers someone writing.

Popper said similar things in The Myth of the Framework (“By criticizing our theories we can let our theories die in our stead.”), In Search of a Better World (“Now we can let our theories die in our place.”), and Natural Selection and the Emergence of Mind (“Let our conjectures, our theories, die in our stead!”).

DD’s associate Chiara Marletto also misquoted Popper as saying "let our ideas die in our place.”.

DD’s associate Sarah Fitz-Claridge misquoted William Godwin and intentionally sanitized a quote about slavery. She gives “The condition of a … slave in the West-Indies, is in many respects preferable to that of the youthful son of a free-born European. The slave is purchased upon a view of mercantile speculation; and, when he has finished his daily portion of labour, his master concerns himself no further about him. But the watchful care of the parent is endless. The youth is never free from the danger of grating interference.”. She misquoted by changing the words "of its grating" to “of grating”. And she sanitized the 1797 quote by changing "negro-slave" into "... slave”. (I think that’s an incorrect use of an ellipsis, too.) Also, the quote is horrible because it downplays how bad slavery was, so it’s disturbing that Fitz-Claridge liked the quote enough to highlight it.

Fitz-Claridge also misquoted The Myth of the Framework. It’s some of the same Popper material misquoted in BoI and on the TCS website, but misquoted differently. This time, Fitz-Claridge changed “that” to “which” and got the page numbers wrong. (More details in the second update.)

Smaller Issues

DD frequently doesn’t give sources for quotes which makes it harder to check their accuracy. By leaving out sources, he’s asking his reader to trust him. But he made many quoting errors, so that trust would be misplaced.

DD repeatedly writes “X … Y” when X and Y are from different paragraphs or even different sections of a book. This is misleading. He also does it when X is a complete sentence, which makes it look like X is not a complete sentence.

DD frequently changes capitalization and punctuation without square brackets to indicate the change. DD capitalizes stuff to make it look like the start of a sentence when it isn’t (both at the start of a quote or after an ellipsis). DD also puts periods inside the quote marks after quoting a partial sentence, which makes it look like that was the end of the sentence when it wasn’t. DD also repeatedly puts a space then an ellipsis after a sentence ends, which should be a period then ellipsis but he changed the period to a space. So he makes stuff look like the start or end of a sentence when it isn’t, and then other times he makes stuff look like it’s not the end of a sentence when it is.

DD doesn’t appear to have a consistent policy for periods going inside or outside of quotes. E.g. I searched an electronic copy of BoI and found 188 instances of a single close quote followed by a period, and 88 instances of a period followed by a single close quote (and 3 instances of period, single close quote, and period again, which all involved a number, ellipsis, close quote, then period). DD often ends quotes with a period inside the quotation marks when the original sentence doesn’t end there, but other times he puts the period outside the quotation marks, and I don’t know why. DD is also inconsistent about italicizing quotes the same way they are in the original.

There are standard guidelines for how to do quotations, which DD violates, in addition to the larger misquote issues I presented above. For example, Working with Quotations, from Suny Empire State College, says:

Remember that when you do choose to use direct quotations, you need to retain the exact wording, spelling, capitalization, and punctuation of the original source.

DD went to both Oxford and Cambridge. I don’t think they teach lower standards than state colleges, and in any case he hasn’t followed their guidelines. For example, this Guide for authors and editors from the Oxford University Press says:

Quoted matter must reflect the original source exactly in spelling, punctuation, and capitalization. Please double-check all quotations against the sources from which you have taken them to ensure that you have copied accurately.

It must be possible for the reader to identify the work from which a quotation has been taken.

The University Of Oxford Style Guide says “Place any punctuation which does not belong to the quote outside the quotation marks (except closing punctuation if the end of the quote is also the end of the sentence).”

The Cambridge Editorial Style Guide says “A full stop is used outside the quotation mark if the quote is only part of a sentence.” and “Always source quotations”.

Taking Credit from Karl Popper

There’s another scholarship issue in DD’s books. I was horrified to discover that Karl Popper’s name is only in The Fabric of Reality (FoR) chapter 3 two times. That chapter is focused on sharing Popper’s ideas. But it doesn’t give adequate credit. In particular, the diagrams (3.1, 3.2, 3.3) are clearly based on Popper’s diagrams in Objective Knowledge, but DD never tells the reader that they’re modified from Popper. (More details.)

DD has presented himself as very humble and modest. He’s claimed multiple times to be only footnotes to Popper (which comes off as exaggerated modesty, rather than convincing his fans that it’s actually true). But DD has simultaneously misled readers to believe he accomplished much more than he did, e.g. in FoR ch. 3. This is a pattern. For example, in a 2016 paper, The logic of experimental tests, particularly of Everettian quantum theory, DD wrote:

An important consequence of this explanatory conception of science is that experimental results consistent with a theory T do not constitute support for T. That is because they are merely explicanda. A new explicandum may make a theory more problematic, but it can never solve existing problems involving a theory (except by making rival theories problematic – see Section 3). The asymmetry between refutation (tentative) and support (non-existent) in scientific methodology is better understood in this way, by regarding theories as explanations, than through Popper's (op. cit.) own argument from the logic of predictions, appealing to what has been called the ‘arrow of modus ponens’. Scientific theories are only approximately modelled as propositions, but they are precisely explanations.

This passage misleads readers into believing that DD improved on Popper by making a better argument focused on explanations instead of on the logic of predictions. Most readers would be surprised to discover that Popper made both arguments. Popper did make the logic of predictions argument (which is less important but was worth making too) but also made the other argument that DD is implying is his own original work. DD made some original contributions to epistemology, but not this one.

You can search Popper’s Conjectures and Refutations (C&R) for words like "tentative", "explanation", and "support" to see that DD is less original than he implies. Popper also covers these issues in other books. I’ll give one example from C&R:

For a scientific theory—an explanatory theory—is, if anything, an attempt to solve a scientific problem, that is to say, a problem concerned or connected with the discovery of an explanation.[6]

This clearly shows that Popper viewed scientific theories as explanatory theories. DD didn’t come up with the idea that scientific theories are explanations. The footnote at the end of that quote refers readers to more of Popper’s writing. Popper talked about explanation often. Popper also came up with the asymmetry between refutation (tentative) and support (non-existent). Popper emphasized refutation, said it was only tentative, and is also the person who challenged thousands of years of philosophical tradition by arguing that support is non-existent. Popper drew multiple major distinctions between negative and positive approaches to epistemology.

DD also gets other people to praise him while he presents himself as humble. For example, his TCS co-founder Sarah Fitz-Claridge (SFC) wrote that Popper invented a philosophy of science and that David Deutsch and his TCS philosophy had extended Popper’s epistemology to apply outside of science. (SFC probably wrote that. It’s on an official TCS page, but doesn’t specify the author, so it could have been written by DD.) That’s a major misrepresentation. Popper was seeking a general theory of knowledge, and said so, and applied it outside of science. (More details.)

DD has gotten his associates to praise him as e.g. having “the greatest mind ever”. SFC believes that DD made major improvements on Popper, and so do many of DD’s fans. I don’t believe it’s an accident that many people overestimate DD in ways similar to his co-founder who publicly promotes him. It looks like a strategy where DD plays humble while having other people say things that would sound arrogant coming from him. (More details.)

In 2012, SFC wrote to the official Fabric of Reality discussion group (archive of FoR posts) (my italics):

In my view it would be much more accurate to say that David has the greatest mind ever to have existed. His thinking is breathtakingly logical and brilliant. His ideas have changed the world and will do so even more profoundly in the future. I have never met anyone more pure, more truth-seeking and more open to criticism than David.

In 2000, SFC wrote to TCS list (my italics):

So really, people should not speak of Popper, but of Deutsch, because it was David who came up with the link between Popper's ideas and educational theory.

Note that DD has a history of secretly ghostwriting stuff which SFC then claims to be the author of. (Source: DD’s friend. He or she was friends with DD before DD turned 18 and they’re still friends now, over 50 years later. He or she had many discussions about TCS, Popper and more with DD and SFC. DD introduced me to the friend and I had some discussions with him or her.) Full disclosure: In the past, I’ve posted a few things that DD wrote, but under my own name, with his permission and approval. I did this when (as best I remember) I wanted to share something good that he told me, which I thought would benefit the world, but he didn’t want to share it himself and wouldn’t let me post it and attribute it to him or to an anonymous person, but he would let me post it under my name without attributing it to anyone. Here’s an example that I remember (I think it was the most significant, memorable instance). More often, I wrote stuff myself that was based on things DD told me, and he didn’t want credit but was happy for me to say it. At other times, DD helped edit my writing and a sentence or two of his ended up in the final version without credit (he didn’t want credit). DD had substantial influence over some of my early writing, and he also has had substantial influence over some of SFC’s writing that he didn’t fully ghostwrite.

Conclusion

I was mistaken about how good DD’s books are. They’re worse than I thought. I still think there is significant value in those books, but you can’t trust DD’s scholarship. Besides distrusting direct quotes given by DD, you should also distrust paraphrases or summaries of what other people said or thought. You have to check things yourself if you actually want to know. DD is too unreliable. And don’t use DD as a secondary source. Don’t spread quotes that DD quoted; quote directly from the original source or don’t use it. Some people are spreading his misquotes (they’ve even been repeated in books).

FYI, I don’t think DD is especially bad at quoting compared to others. Lots of books and academic articles have major errors related to quotes, paraphrases, cites or facts. But for a book to be considered great, it should do better. In the world today, you shouldn’t trust authors with quotes or facts by default. You should be suspicious by default unless an author earns more trust. Many people believe DD has earned a lot of trust (including me in the past), but they’re mistaken.

I apologize for encouraging people to respect and trust DD more than he merits. I know I played a role in that.

DD’s misquote problem also helps contextualize his recent mistreatment of me. How could a super rational, great person act like that? The answer is that he he’s actually a deeply flawed person with some good traits mixed in as special exceptions.

DD once got very upset with me for questioning a Godwin quote he sent me in a private discussion. He’d sent it without a specific source and I couldn’t find the quote by searching the book. It turned out that he’d quoted an obscure first edition but I was searching the third edition. He should have praised me for looking for errors instead of getting defensive and lashing out at me. Good scholars don’t expect to be trusted and don’t mind being questioned or challenged. Even though he didn’t misquote in that instance, DD’s irrational attitude was a warning sign that DD might be a misquoter. I failed to recognize the full problem and I didn’t go fact check his books at that time (2011).

BoI has an errata page (mirror) which documents a bunch of errors in the book. They are mostly factual errors, and the number and severity should concern readers. Despite all the misquotes in the book, there are currently no misquotes on the errata page, which says something about how little fact checking the book has been getting (there are probably a bunch of other errors that no one has found yet).

I will edit my book recommendation articles to warn people about DD’s misquotes. I will also take down the beginningofinfinity.com website that promotes BoI and put a warning there about DD’s misquotes.

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Update, 2021-07-12: In a 1985 physics paper in a prestigious, peer-reviewed journal, David Deustch misquoted Alan Turing.

Update, 2021-07-13: I made two videos related to DD misquotes:

Video about the Feynman misquote: "Science is what we have learned about how to keep from fooling ourselves.". This video goes into more depth.

Video about this blog post about DD's misquotes. This video is more of a broad overview.