Symposium held at the University of Connecticut on May 24, 2024
convened by Matthew Mandelkern (NYU) and Stefan Kaufmann (UConn)
Heritage Room (4th Floor, Rm. 4118), Homer Babbidge Library
369 Fairfield Way, Storrs, CT
The relationship between the probability of a conditional ‘if A, C’ and the conditional probability of C given A has long been one of the most hotly debated topics in epistemology and philosophy of language, as well as more recently in psychology and linguistics. The 1970’s saw groundbreaking work in this area, including Stalnaker’s (1970) proposal to identify the two probabilities, sometimes known as “Stalnaker’s Thesis” or simply “The Thesis”; Lewis’s (1976) argument that The Thesis is seriously at odds with certain deeply entrenched assumptions about truth conditions and the semantics of conditionals; and van Fraassen’s (1976) ingenious proposal to resolve the tension by adopting a new kind of model theory. In van Fraassen’s models, possible worlds are replaced with sequences of possible worlds. This move solves a surprising number of problems. But it took several more decades of arguments and counterarguments, scrutinizing the topic from every conceivable angle, before researchers began in earnest to explore such world sequence models as an alternative to conventional possible-worlds models. Since the aughts of the new millenium there has been a slew of new proposals and results in this arena, enough to warrant a moment of reflection to take stock and exchange some ideas. Our symposium is meant to provide a forum for this discussion. It brings together two of the original pioneers – Bas van Fraassen and Robert Stalnaker – and a group of younger scholars who have been drivers of the recent surge of interest in the topic.
convened by Matthew Mandelkern (NYU) and Stefan Kaufmann (UConn)
Heritage Room (4th Floor, Rm. 4118), Homer Babbidge Library
369 Fairfield Way, Storrs, CT
The relationship between the probability of a conditional ‘if A, C’ and the conditional probability of C given A has long been one of the most hotly debated topics in epistemology and philosophy of language, as well as more recently in psychology and linguistics. The 1970’s saw groundbreaking work in this area, including Stalnaker’s (1970) proposal to identify the two probabilities, sometimes known as “Stalnaker’s Thesis” or simply “The Thesis”; Lewis’s (1976) argument that The Thesis is seriously at odds with certain deeply entrenched assumptions about truth conditions and the semantics of conditionals; and van Fraassen’s (1976) ingenious proposal to resolve the tension by adopting a new kind of model theory. In van Fraassen’s models, possible worlds are replaced with sequences of possible worlds. This move solves a surprising number of problems. But it took several more decades of arguments and counterarguments, scrutinizing the topic from every conceivable angle, before researchers began in earnest to explore such world sequence models as an alternative to conventional possible-worlds models. Since the aughts of the new millenium there has been a slew of new proposals and results in this arena, enough to warrant a moment of reflection to take stock and exchange some ideas. Our symposium is meant to provide a forum for this discussion. It brings together two of the original pioneers – Bas van Fraassen and Robert Stalnaker – and a group of younger scholars who have been drivers of the recent surge of interest in the topic.
Schedule (tentative!)
Friday, May 24 | |||
8:45- 9:00 | Opening | ||
9:00-10:00 |
Robert Stalnaker,
MIT
In van Fraassen’s, Probability and conditional”, he responds to David Lewis’s triviality result by identifying and rejecting an implicit premise that was crucial to Lewis’s proof, a premise concerning the independence of the truth-conditions for conditionals from the probability judgments about those conditionals. This premise, he wrote, must have been motivated by Lewis’s metaphysical realism, “according to which one should always be able to say: let the possible worlds in my model structure be those which there actually are.” In my response at the time, I acknowledged that Lewis’s proof depended on this premise, but argued that one can get the same triviality result without it, so long as one made an assumption about that the logic of conditionals that I, at least, was prepared to make. In this talk, I want to explore the relationship between general philosophical theses about metaphysical realism and specific theses (such as Lewis’s implicit premise) about connection between truth-conditions (in a model) for conditionals and probability values. Van Fraassen’s own view was that “counterfactual conditionals do not have the function of stating facts, and in a strict sense, none deserve to be called true or false,” but a metaphysical realist who rejects this bold anti-realist thesis (as I do) may still allow for conceptual connections between propositions that make factual claims and propositions (such as probability judgments) about the epistemic status of those claims. |
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10:15-11:15 |
Cian Dorr,
NYU
tba |
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11:30-12:30 |
Snow Zhang,
UC Berkeley
tba |
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12:30- 1:30 | Lunch break | ||
1:30- 2:30 |
Calum McNamara,
University of Michigan, Ann Arbor
A prominent challenge for Bayesians is to say how your credences should change when you learn an indicative conditional. A number of cases in the literature seem to show that the standard Bayesian update rules—conditionalization and Jeffrey conditionalization—give implausible results when you learn conditionals of this kind. The most famous of these cases is Bas van Fraassen’s Judy Benjamin problem, where it's shown that if, after learning an indicative conditional, your credences satisfy some intuitive desiderata, then you can't be updating in accordance with standard Bayesianism. In response to this case, some authors have argued against van Fraassen's desiderata, while others have given additional updating rules, intended to supplement standard Bayesianism. In this talk, however, I’ll argue that both kinds of response are mistaken. I'll first draw a connection between the Judy Benjamin problem, on the one hand, and the thesis known as Stalnaker's thesis, on the other. Stalnaker's thesis—which relates your credences in indicative conditionals to your conditional credences—was for a long time thought to be untenable, owing to the famous triviality results of Lewis and others. However, recent work has shown that, given a sophisticated contextualist view about indicative conditionals, this thesis is tenable after all. In the talk, I’ll show that, given the same contextualist view of indicative conditionals, the standard Bayesian update rules can satisfy all of the intuitive desiderata in van Fraassen’s case. I’ll then show that certain alternatives to the Bayesian rules actually turn out to be equivalent to those rules in particular contexts. Thus, what we end up with is a nice, unified account of rational learning—one which fits well with recent work on the semantics of conditionals, and on Stalnaker's thesis more specifically. |
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2:45- 3:45 |
Melissa Fusco,
Columbia
tba |
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4:00- 5:00 |
Bas van Fraassen,
SFSU
I will argue for three claims. First, that lack of closure under conditionalization is ubiquitous and not a fault. Second, that the CCCP (Stalnaker’s Thesis) has consequences for our basic concept of the relation of logical consequence. Third, that Alan Hajek’s view, that conditionals are true only if the corresponding conditional probability equals 1, can receive a tenable formulation by relinquishing possible world semantics. |
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