PHL246H1 Lecture Notes - Logical Consequence
Document Summary
The swan-hypothesis h is a universal if-then sentence and says that all swans are white. H is logically equivalent to the universal if-then sentence h" that everything that is not white is not a swan. H is also logically equivalent to the universal if-then sentence h"" that everything that is or is not green is not a swan or is white. The nicod criterion nc says that universal if-then sentences of the form all fs are gs are confirmed by their instances of the form a is f and a is g. The equivalence condition ec says that if evidence e confirms one hypothesis f, then evidence e confirms any hypothesis g that is logically equivalent to f. Use nc and ec to show that each of the three claims e1, e2, and e3 confirms the swan-hypothesis h. (3 points) The entailment condition entc says that evidence e confirms hypothesis h if evidence e logically implies hypothesis h.
