Paul Alper writes:
In recent months I have been mumbling that no one else seems to recognize that Bayesian Revision needs revision because on an empirical basis, humans unlike machines, ignore evidence that contradicts a prior belief—the House Committee is on tonight and I will be glued to what transpires* even though my priors indicate nothing will move the needle. Then I discovered that I am very late to this party regarding doxastic logic.
From Wikipedia:
In all your blogging items, has doxastic ever been mentioned by anyone?
*Transpired is an interesting word to me because, as incredible as it may seem, the synonym used today for it, i.e., happened, was fiercely opposed in the 1920s. The preferred synonym was limited to perspired.
My response: I’ve never heard the term “doxastic” before, but this discussion reminds me of the distinction between evidence and truth, which I’ve discussed in many places (for example here and here) and which I think causes no end of troubles among scientists who conflate these two ideas.
Of course it has been mentioned, perhaps not surprisingly, by me in a post about this very topic. Usually it’s just me and Keith O’Rourke talking to each other in philosophical terms, so not surprising that Andrew doesn’t remember this old comment.
How else would an academic talk about belief (doxastic) vs. knowledge (epistemic) if not by invoking obscure latin nomenclature? To relate epistemic and doxastic logics, you typically have an axiom that says if you know something, then you also believe it, because the analytic philosophers liked to think of knowledge as justified true belief. This is problematic for a lot of reasons and you can make an entire career in philosophy exploring this boundary.
I do not think that the axiom Paul Alper cites, that if you believe x, you believe you believe x, is true of real people’s beliefs. People can believe things in some sense but not believe they believe them. For example, one might believe in some kind of miracle cure without believing you believe in miracles. To trot out some more classical terminology, the axioms Paul Alper and I cite are what economists would call “normative” (what consistent reasoners should do) rather than “descriptive” (what people actually do). But it’s all semantics in terms of how we define what the words “belief” and “knowledge” mean in a technical context.
P.S. For anyone who wants to search the blog, you can do site specific Google searches like the one I did to find my old post: [site:statmodeling.stat.columbia.edu "doxastic"]. The site also has a search box, but it doesn’t work.
P.P.S. If you want to learn more and you like higher-order or modal logic, check out the sections of my semantics book on intensionality and higher-order modal logic. I used to teach this material every year back when I was a professor working on a mix of programming language and natural language semantics (I apply the former to syntactic theory in my first book).
Bob:
If you’re into convenience, the more economical doxastic inurl:statmodeling also works
John
> because the analytic philosophers liked to think of knowledge as justified true belief
My recollections from taking a few epistemology & philosophy of language courses in ugrad a decade ago was that Gettier ’63 conclusively buried JTB, but in retrospect the prof favored his own specific flavor of infinitism that did not require us to believe something true to know it? I think? Time has not made the view less confusing.
Looking at the 2020 PhilPapers results (https://survey2020.philpeople.org/survey/results/4982), though, only 24% of respondents endorse JTB inclusively. And 80% of respondents overall identified with the analytic tradition (https://survey2020.philpeople.org/survey/results/demographics). Per 3.4 here https://philarchive.org/archive/BOUWDP, I guess they calculated correlations by… coding binary responses numerically and taking the Pearson correlation between them? And then reported in that first link all the correlations that pass a p < 0.05 significance filter, which "Tradition: *" did not. So it sounds like most analytic philosophers today don't endorse JTB, but I guess *liked* is past tense, so maybe Gettier '63 & follow-ups took a little while to set in? Not as familiar with the history of it, and the '09 survey didn't ask that question.
The “qbists” (formerly known as quantum bayesians) like to refer to their interpretation of quantum mechanics and more doxastic than epistemic. See, for example, https://arxiv.org/abs/1911.07386, https://arxiv.org/abs/1810.13401
An election is coming up in a few weeks, and as evidence of my claim that Bayesian revision is aspirational, or as Bob Carpenter put it, normative–and does not apply to human behavior, consider the election denier and insurrectionist, Couy Griffen:
“My vote to remain a no isn’t based on any evidence, it’s not based on any facts, it’s only based on my gut feeling and my own intuition, and that’s all I need.”
Griffin is, or was, a NM County Commissioner
https://en.wikipedia.org/wiki/Couy_Griffin
He stands out in this large field of U.S. citizens who hold on to deluded fantasy–and are running for government office–only because he is straightforward, gives the game away and is always pictured in an oversized cowboy hat.
Further evidence of the in-applicability of Bayes revision applied to humans, is of course, my refusal to change my mind on the subject.
Somewhat related to this thread:
https://getpocket.com/collections/how-to-talk-to-a-science-denier-a-reading-list?utm_source=pocket-newtab
Hi, Andrew.
Didn’t you mean to title this blog post with “It’s . . . doxastic!” instead of “It’s . . . doxtastic!”?