I'm in a beginning logic class and so far we have learned four rules: Assumption, Modus Pollens, Double Negation and Modus Tollens. I understand everything but Modus Tollens. The other downside is ...

Abstract: The article begins by focusing a property which N. Goodman in his celebrated 1947 essay ascribes to counterfactual conditionals, i.e. that every counterfactual may be converted by ...