Upcoming Events

The next event is on Thursday, September 3rd:

LIRa session: Edoardo Baccini


Speaker: Edoardo Baccini (MCMP, LMU München)

Date and Time: Thursday, September 3rd 2026, 16:30-18:00

Venue: online only.

Title: Commutativity, Contingency of Beliefs and How Early Interactions Shape Future Beliefs

Abstract. Commutativity principles state that what one comes to believe upon learning several pieces of evidence should be independent of the order in which distinct pieces have been acquired. Within the Bayesian paradigm to belief revision, commutativity is violated by a number of popular Bayesian network frameworks to model belief change on the basis of testimonial information, where the source of information could be telling truths, falsehoods or simply guessing. This talk considers the consequences of commutativity violation within such frameworks: Do one’s beliefs become contingent in the sense that they could have been different had the same evidence from the same source been presented in a different order? If one’s beliefs are contingent, what aspect of the presentation order prompted the agent to accept a particular belief instead of another? Via computer simulations, we show that beliefs are contingent whenever the information provided creates a friction in the agent’s expectation, i.e., whenever a trusted (distrusted) source provides implausible (plausible) evidence. Second, we illustrate that, whenever contingent, the beliefs one forms are largely shaped by the earlier pieces of evidence that a source discloses. Finally, we discuss some philosophical implication of our analysis for the epistemology of expertise, for norms of evidence disclosure and for science communication. (Joint work with Lilian von Bressensdorf and Michela Cimarelli)

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