Behavioral and Brain Sciences

Open Peer Commentary

Classical logic, conditionals and “nonmonotonic” reasoning

Nicholas Allotta1 and Hiroyuki Uchidaa1

a1 Department of Linguistics, University College London, London WC1N 1PF, United Kingdom. [email protected] [email protected]


Reasoning with conditionals is often thought to be non-monotonic, but there is no incompatibility with classical logic, and no need to formalise inference itself as probabilistic. When the addition of a new premise leads to abandonment of a previously compelling conclusion reached by modus ponens, for example, this is generally because it is hard to think of a model in which the conditional and the new premise are true.

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