Certain Doubts

Let S be a set of beliefs and experiences that is the evidence on which we are going to apply defeasible reasoning. Then suppose we have propositions p1…pn with the following properties:
1. S |~ p1 (p1 is a defeasible consequence of S).
2. S U p1 |~ p2 (p2 is a defeasible consequence of the union of S and p1).
.
.
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n. S U p1…pn-1 |~ pn.

Question: what does it take for this sequence of belief revisions matching this sequence to result in the belief that pn to be rational or justified?

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Literature question: is there anything out there about epistemic constraints on, or an epistemic rationale for, the use of Jeffrey conditioning? Dick Jeffrey was, himself, a radical personalist, so he had little to say about the conditions under which it might be rational to update via his famous formula. But plenty of non-personalists are interested in questions about conditionalization. I’m familiar with, e.g., Kyburg, Thalos and Bacchus’s article “Against Conditionalization,” but I’m looking for something with a positive moral as well as purely critical literature. There are some interesting considerations that I would like to see taken into account; but why reinvent the wheel if it’s rolling around out there somewhere? Feel free to offer pointers, particularly to any articles on the rigidity of likelihoods in conditionalization.

One of my interests is to see greater interaction between traditional approaches to epistemology and more formal approaches to epistemology, including Bayesian epistemology, confirmation theory, learning theory, and whatever other stuff is done by the really neat group of contributors we now have in this area: Fitelson, Wheeler, Hawthorne, Joyce, Armendt, Gillies, Roush, Weiner and others (I’m going from memory here, and may be leaving some out, so please feel from to complain about my sorry memory…).

So far, the experiment is a hit. Just look at the interest of such posts in terms of numbers of comments, both by the formalists and the traditionalists. Very neat, I say!

If you’re a contributor and would like to email me with suggestions to include more people who work on the formal side, please do so and I’ll contact them.

This is in response to Ralph’s post just below, and I’m putting it here in hopes that more people will see it.

I’ve put in controls to keep spammers out, and the controls often kick in on ordinary comments. When they do, I receive an email asking that the comment be approved, which I do as soon as I see the email.

This practice leads to some delays, but it keeps the site free from poker advertisements. For one example, over the weekend, we received more than 150 comments from such advertisers. 3 got through, since they’ve now resorted to using the trackback feature to get on the site, but I’ve fixed that problem as well.

I apologize for the frustration caused by these controls, and whenever anything goes wrong on the site, I hope all who read the blog know that I welcome emails to keep the site functioning properly.

I tried posting a long reply to Ram as a comment on the last thread, but somehow, my attempt to post the comment seems not to have worked, and I lost my comment in the process as well.

Jon, could you just check to see if there are any problems with the site? I’ll try reconstructing my comment tomorrow, and see if I can post it then.

Ram just sent me a work-in-progress entitled “An Internalist Refutation of Fallibilism”. The thesis is provocative: if internalism is true, then fallibilism is false. Comments welcome!

I just got my copy of Contemporary Debates in Epistemology, edited by Steup and Sosa. It looks great! Here’s the Blackwell’s link and here’s the Amazon link.

The posting “Jim Hawthorne on the Logic of Nonmonotonic Conditionals” took a rather technical turn (which was my fault–sorry!!!). This posting is addressed to readers of the blog more generally. In it I will describe much about defeasible conditionals that experts already know, though they may disagree with the interpretative spin I’ll give. This posting is intended to provide one take (my take) on what certain kinds of defeasible conditionals represent that may be of interest to epistemologists. I’d be interested in whatever anyone thinks of this.

With regard to the logic of defeasible conditionals, I think that the most central issues for epistemologists are:

1. What “exactly” are defeasible or nonmonotonic conditionals such as those in system R (the rational consequence relations) supposed to represent? and how precisely are they supposed to be relevant to knowledge or belief? and

2. How does each particular semantic basis or model theory (e.g. Popper functions, Popper measures (which I’ve been calling “vF functions”), preferential models, etc.) illuminate whatever it is that these conditionals are supposed to represent (in a way that is useful to epistemology)? Skip the technicalities — what is it supposed to represent, intuitively? And does it succeed?

I’ll take a stab at part of this. I’ll focus on the R conditionals.

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Harry Frankfurt has just published On Bullshit with Princeton University Press. An excerpt and links to the paper on which it was based and an interview with Frankfurt on “Marketplace” can be found here. I found the essay upon which this small book is based to be very engaging and illuminating.

A word of caution: it will be very hard to find a conception of epistemology on which this post counts as that. It’s on the conditional fallacy, but the context of discussion is the nature of dispositions. So I’m going to put the content of the post below the fold. My defense at violating the epistemological purity of the site is that so many instances of the fallacy crop up in epistemology that clarity about the fallacy (if there be such a fallacy) is important in epistemology.

I posted earlier linking to the paper by Bonevac, Dever, and Sosa on the fallacy, and then emailed David about it, and he’s amenable to discussing the paper here on the blog so others can join in as well if they choose, or just enjoy reading. So here goes.

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