Homework assignment 2 (due October 3, 2013)
The swan-hypothesisH 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 Econfirms one hypothesis F, then evidence E
confirms any hypothesis Gthat is logically equivalent to F.
Your evidence consists of three claims: E1 = “a is a swan and a is white”, E2= “b is not white and bis not
a swan”, E3 = “(c is green or c is not green), and (c is not a swan or c is white).”
Use NC and EC to show that each of the three claims E1, E2, and E3 confirms the swan-hypothesisH.
The Entailment Condition EntC says that evidence E confirms hypothesis H if evidence E logically implies