Proceedings of the Annual Meeting of the Cognitive Science Society

Conditionals pervade every aspect of our thinking, from themundane and everyday such as ‘if you eat too much cheese,you will have nightmares’ to the most fundamental concernsas in ‘if global warming isn’t halted, sea levels will rise dra-matically’. Many decades of research have focussed on thesemantics of conditionals and how people reason from condi-tionals in everyday life. Here it has been rather overlookedhow we come to such conditionals in the first place. In manycases, they are learned through testimony: someone warns usabout the ill-effects of cheese. Any full account of the condi-tional must consequently incorporate such learning. Here, weprovide a new formal account of belief change in response to atestimonial conditional.