Iterated Conditionals: Normative and Descriptive Models

SPEAKER

Horacio Arlo-Costa

ABSTRACT

The talk is divided in two parts. The first part presents a critical overview of
recent normative work on iterated conditionals. The focus is on epistemic and probabilistic
models. Regarding iteration to the right the talk discusses a probabilistic model based on
ideas presented in [1] and extensions of this idea obtained by adopting an axiomatization
of probabilistic update first proposed in [2]. Regarding iteration to the left we present
and compare the epistemic theory presented in [3] and the alternative epistemic account
presented in [6]. Some common problems are mentioned. Finally we consider critically
the probabilistic theory (covering all forms of iteration) presented in [5].
The second part of the talk considers some descriptive theories of conditional reason-
ing. We focus on the theory of mental models presented in [4] and consider its applicability
to study the behavior of iterated conditionals. We claim that the theory makes incorrect pre-
dictions regarding the difficulty in processing left and right nested conditionals. We con-
clude with some considerations about the limitations and problems of various descriptive
approaches (including the probabilistic account presented in [7]) and sketch an alternative
(that takes into account recent empirical work on belief revision and supposition [8]).

REFERENCES

[1] H. Arlo-Costa, Bayesian Epistemology and Epistemic Conditionals: On the Status of the Export-Import
Laws, Journal of Philosophy, Vol. XCVIII, 11, 2001, 555-598.
[2] P. Gardenfors, Knowledge in Flux: Modeling the Dynamics of Epistemic States (Studies in Logic: Mathe-
matical Logic and Foundations), College Publications, 2008.
[3] S. O. Hansson, In Defense of the Ramsey Test, Journal of Philosophy, 89 (10), 1992, 522-540.
[4] P. N. Johnson-Laird and R. M. J. Byrne, Conditionals: A Theory of Meaning, Pragmatics, and Inference,
Psychological Review, Vol. 109, No. 4, 2002, 646 678.
[5] H. Leitgeb, A Probabilistic Semantics for Counterfactuals, manuscript, 2009.
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probabilistic approach? In M. Oaksford & N. Chater (Eds.), Cognition and conditionals: Probability and
logic in human thought. Oxford: Oxford University Press, (in press).
[8] C. Walsh and P. N. Johnson-Laird, Changing your mind, Memory & Cognition, 37, 2009, 624-631.