Dennis Hackethal Falsely Implied That Critical Fallibilism Plagiarizes Karl Popper
Dennis Hackethal has been writing about Critical Fallibilism's (CF's) core ideas, on his Veritula website, but he doesn't name or credit CF or me. Instead, he claims the ideas were invented by Karl Popper and are part of Popper's philosophy, Critical Rationalism (CR). Because CF is partially based on CR, this claim may seem superficially plausible, so I'll address it.
CF agrees with CR's approach to fallibilism, error correction, evolutionary epistemology, and criticizing induction and justificationism. Although these ideas are included in CF, they should be credited to Popper.
CF also has original ideas which are different than CR. A motivation for developing CF was to improve on CR.
Unlike CR, CF claims that ideas should be evaluated in a binary way as non-refuted or refuted using decisive arguments. CF says not to evaluate ideas or arguments quantitatively on a spectrum using amounts or degrees: don't evaluate how much weight arguments have, how strong or weak criticism are, how good or bad ideas are, etc. CF rejects indecisive arguments and says a single non-refuted criticism refutes an idea, and we should never accept or act on refuted ideas. With a binary viewpoint (CF), each criticism should be addressed; it's a mistake to call a criticism small and dismiss it. With a quantitative viewpoint (CR and many others), one criticism often doesn't have enough weight to tip the scales.
CF's position is laid out on its homepage and in many essays going back many years and more recently and there are even more (and paid products).
CF, unlike CR, also uses tree diagrams extensively, including debate trees (more links and videos). Trees are a well known tool, but some ways CF uses trees are unique.
CF was developed by me, Elliot Temple. It took over 10,000 hours of largely unpaid effort while I worked other jobs, outside of philosophy, to support myself. I believe I've come up with some important, original ideas. I'm happy with my accomplishment even if it isn't yet prestigious, popular or profitable. I've shared most of my ideas for free online, but I do want credit when people like and use my ideas.
I wrote a separate essay sharing evidence that Hackethal's Veritula uses CF ideas without attributing them to CF. This essay shows that CF is different than CR and therefore doesn't plagiarize CR.
Hackethal's Claims
For context, Hackethal came to me as a student in 2018. He paid for my help learning philosophy. For months, he participated at my chatroom and email discussion group. He's been familiar with my work for seven years, has read a lot of it, and has written over 50,000 words about me. Here's a timeline.
Now let's look at examples of what Hackethal has been claiming (mirror) about his website, Veritula, and its debate tree tool. All block quotes in this section are from Hackethal, and from that link, unless otherwise specified.
Veritula is a programmatic implementation of Popper’s epistemology.
and
Veritula follows, and helps you apply, Karl Popper’s epistemology, Critical Rationalism.
This credits Popper, although quotes and sources aren't provided. Veritula is actually a programmatic implementation of CF's debate tree idea. I also had a long discussion about programmatic implementation in 2020.
Popper’s epistemology operates on contradiction and non-contradiction. It does not assign strengths or weaknesses.
Popper does assign degrees of strength (also called weight, goodness or force) or weakness to ideas, arguments and evidence. Here are previews of the Popper quotes I share later in this article:
- "strengthening of the thesis"
- "weaker theories"
- "strong arguments"
- "when the evidence for [those ideas] is extremely strong"
- "degrees of 'goodness'"
- "greater weight"
- "assess the weight of arguments"
If you can think of neither a revision of [an idea] nor counter-criticism to [a criticism of that idea], your only option is to accept that [that idea] has been (tentatively) defeated. You should therefore abandon it, which means: stop acting in accordance with it, considering it to be unproblematic, etc.
If [the proponent of an idea] fails to address even a single criticism, the idea remains problematic and should be rejected.
CR says arguments can be weak or inconclusive, so not all criticisms require us to reject or abandon their target. Popper quote previews: "weighty though inconclusive arguments" and "our arguments are never conclusive".
Philosopher David Miller wrote books on CR. He was Popper's research assistant and co-authored papers with Popper. Miller quote preview: "[science] may also allow falsified hypotheses to be retained".
Critical Rationalism says that ideas are assumed true until refuted.
CR doesn't assume non-refuted ideas are true. Popper quote preview: "we do not prefer every non-falsified theory".
Veritula does not implement Deutsch’s epistemology. It implements Popper’s. I don’t think they’re compatible. [source, mirror]
Hackethal claims, without evidence, that David Deutsch misunderstood Popper. Deutsch's first book, The Fabric of Reality was "Dedicated to the memory of Karl Popper ... This book takes [his] ideas seriously." Popperian epistemology is one of the book's four main "strands". Popper is named 82 times.
Deutsch's other book, The Beginning of Infinity, names Popper 60 times. Here's Popper's index entry:
Popper, Karl 4, 10, 14, 17–18, 66, 104–5, 114,, 210, 211, 215, 230n, 312, 403–4, 406, 409, 447, 460–61
criterion of demarcation for science 14 see also testability
criterion of ridding ourselves of bad governments without violence 209–12, 344–51, 352, 396, 423
on our infinite ignorance 447
on instruction 411–12
on ‘sources of knowledge’ 209
theory of knowledge in ‘a dream of Socrates’ 223–54
letting theories die in our place 114, 124
and optimism 196, 212, 215
on prediction and prophecy 198
on ‘who should rule’ 209
(I confirmed that the "114,," typo is in my hardback copy not just my ebook.)
Deutsch considers himself a Popperian. He was my mentor and taught me about Popper. He's widely considered a Popperian. But Hackethal (while providing no evidence) says actually Deutsch isn't a Popperian: he has a different, incompatible epistemology. This challenges Deutsch's whole philosophy career: his books and Taking Children Seriously parenting philosophy are supposed to be based on Popper's epistemology. While I have issues with Deutsch, I do think he has a good understanding of Popperian epistemology.
Hackethal doesn't specify whether he thinks Deutsch misunderstood Popper's epistemology or Deutsch disagreed with it (while misleading claiming he was a Popperian, rather than explaining the disagreement).
Some people are believing Hackethal's claims. Popperian author Edwin de Wit responded to Hackethal:
Great clarification of Popper’s position—and of how it differs from Deutsch’s. Very insightful.
Does CF Plagiarize Popper?
By talking about CF ideas and attributing them to Popper, Hackethal is implying that CF plagiarizes Popper. He's also implying that many people misunderstood Popper, like Deutsch, Miller, Shearmur, Agassi, Medawar, Hayek, Firestone, Eccles, Champion, Feynman, Szasz, Bartley, Musgrave, Lakatos, Feyerabend and Kuhn.
If Hackethal is incorrect, he's being unfair to both me and Popper. It's mistreatment of Popper to attribute controversial, unpopular ideas to him that he didn't believe. It causes confusion among fans of Popper and can cause non-fans to be dismissive of Popper.
If Hackethal is correct, he ought to explain to people what they missed in Popper's books, using quotes and sources. He ought to present his superior reading of Popper as a major philosophical accomplishment because it would be one. Instead, he casually attributes these ideas to Popper like everyone already agrees this is what Popper said, but they don't.
In general it's difficult to prove a negative like that Popper did not say something. But Popper contradicted CF in most of his books, so we can just examine quotes. Italics are in the originals; bold is added to highlight ideas that contradict CF. For brevity, sources (which are all Popper books unless otherwise stated) are in brackets at the end of quotes.
One may sometimes offer strong arguments and one can always investigate various views critically; yet excepting mathematics, our arguments are never conclusive. We must always assess the weight of arguments and of reasons; we must always decide or judge which of them have greater weight; those for a given view, or those against it. [In Search of a Better World]
Out of many other weighty though inconclusive arguments I wish to mention only one. [Objective Knowledge]
observation and experiment certainly play an important part in the critical discussion of scientific theories. Essentially, they help us to eliminate the weaker theories. [The Myth of the Framework]
The following argument in support of the conjecture that the Way of Opinion was conceived by Parmenides prior to his revelation is admittedly weak but perhaps not without all force. [The World of Parmenides]
gross departures from the historical tradition must only be accepted when the evidence for them is extremely strong [Conjectures and Refutations]
This paper attempts to provide both and elaboration and a strengthening of the thesis ... [Why Probabilistic Support is not Inductive, a paper by Karl Popper and David Miller]
CR evaluates the strength or weight of arguments, ideas or evidence. CF says that's a mistake and uses decisive criticism and binary evaluations instead.
all these ideas bear on the degrees of 'goodness' of the competing theories [Objective Knowledge]
The narrowest reference-class may often be the most suitable, provided that it is numerous enough to allow the probability estimate to be based upon reasonable statistical extrapolation, and to be supported by a sufficient amount of corroborating evidence. [The Logic of Scientific Discovery]
Nevertheless we can claim that in deciding to prefer one theory to another (say, because of its higher degree of corroboration), we proceed in a perfectly rational way—in the way of the searcher for truth, though not in the way of the possessor of truth. [The Philosophy of Karl Popper, volume 2, edited by Paul Arthur Schilpp]
These considerations show that the belief in the truthlikeness of well-corroborated results of science (such as the laws of mechanics) is indeed rational, and remains so even after these results have been superseded. Moreover, it is a belief capable of degrees. [Realism and the Aim of Science]
I introduced degrees of testability, and these turned out to be closely related to (degrees of) content, and surprisingly fertile: increase of content became the criterion for whether we should, or should not, tentatively adopt an auxiliary hypothesis. [Unended Quest]
we are interested in theories with a high degree of corroboration. [Conjectures and Refutations]
CR evaluates and compares ideas by degrees or amounts of positive or negative traits (like goodness, corroboration, testability or content). CF says that's a mistake and instead uses decisive criticisms to refute ideas and reach binary evaluations.
we should prefer as basis for action the best-tested theory.
In other words, there is no 'absolute reliance'; but since we have to choose, it will be 'rational' to choose the best-tested theory. This will be 'rational' in the most obvious sense of the word known to me: the best-tested theory is the one which, in the light of our critical discussion, appears to be the best so far, and I do not know of anything more 'rational' than a well-conducted critical discussion. [Objective Knowledge]
The only correct answer is the straightforward one: because we search for truth (even though we can never be sure we have found it), and because the falsified theories are known or believed to be false, while the non-falsified theories may still be true. Besides, we do not prefer every non-falsified theory—only one which, in the light of criticism, appears to be better than its competitors: which solves our problems, which is well tested, and of which we think, or rather conjecture or hope (considering other provisionally accepted theories), that it will stand up to further tests. [Conjectures and Refutations]
CR evaluates how good ideas are and compares to see which are better. CF says that's a mistake: we should give ideas binary evaluations as non-refuted or refuted (for goals in contexts).
I've read and reread a lot of Popper's writing, read literature about Popper, thought about Popper's ideas, wrote about Popper, participated at many Popper discussion forums. To the best of my knowledge, these quotes are representative of Popper's thinking.
When I've talked with Popperians about CF, none have ever responded saying that was actually Popper's position. David Deutsch disagrees with CF. David Miller was dismissive of CF and wrote in his book, Critical Rationalism: A Restatement and Defence:
Indeed, [science] may also allow falsified hypotheses to be retained, provided that there is some weight of negative evidence that would eventually cause them to be banished.
Retaining hypotheses despite criticism/falsification contradicts CF. Adding up weights of negative evidence, and rejecting ideas when there is a large enough quantity/strength of criticism, contradicts CF.
Is This an Accident?
Is it plausible that Hackethal is simply confused about what Popper said? I don't think so. I spoke with him about this on a call when he paid for my help learning philosophy. You can read quotes from the call recording here including "Hackethal: So Yes or No Philosophy [a part of CF] is your philosophy that addresses shortcomings in both Popper's and Deutsch's philosophies?"
In 2019, I sent him a 59 page document, CONFIDENTIAL DRAFT Critical Fallibilism Website.pdf, which says:
Elliot Temple’s improvements [to Karl Popper's Critical Rationalism] include:
– Yes or No Philosophy explains that ideas should be judged in a binary way: non-refuted or refuted. We can always act on non-refuted ideas, despite having limited resources such as limited time.
At the time, I was calling some of CF's ideas "Yes or No Philosophy" because they involve evaluating ideas in a binary way. Yes or no is a binary choice and binary refutation status is used to decide which ideas to say yes or no to (tentatively, fallibly accept, use, believe, conclude, etc.). I still sell a Yes or No Philosophy educational product. The free marketing material includes an essay summarizing the idea and discussing how it's different than CR.
Read more from the confidential document here. It includes the section titles "All Criticisms Are Decisive", "Yes or No Philosophy" and "Non-Refuted". It contains CF ideas like "The idea of strong or weak arguments is a mistake."
Hackethal is familiar with many of the CF essays linked throughout this article. We talked on a call about CF and he has a confidential draft of the CF website. He's well aware of who I am and what I've written. He's written over 50,000 words about me. I don't see how this could be an accident.
Suppose hypothetically that Hackethal believed these were my ideas when I told him that in 2019, but, years later, he found that the ideas were in Popper's books all along. That would be, by far, the most important philosophical discovery of his career. He would have outdone all the Popper experts. To explain his discovery, I think he would have at least written one essay with quotes and citations. (Also, he's written tens of thousands of words attacking me. I think he'd definitely write an accusation that I plagiarized Popper if he had evidence.)
Conclusion
Popper didn't invent CF's ideas. He contradicted them in book after book. I hope that if Popper were alive, he would be curious about CF and discuss it. He could come to agree or share constructive criticism. But CF doesn't plagiarize CR. Hackethal is spreading confusing misinformation about Popper's ideas. Popper, being deceased, can't set the record straight, so I'm trying to.
Hackethal based the Veritula website on CF's ideas without attributing them to CF. He's actively and repeatedly writing about CF ideas without crediting me. This reminds me of when he added hundreds of citations in the second edition of his book due to plagiarism complaints (in my opinion, he still hasn't solved that problem). But this is worse than plagiarism.