Source: p 110. Sweet Reason: A Field Guide to Modern Logic (2010 2 ed) by Henle, Garfield, Tymoczko.
The following statements are all about schools. Here is some partial information:
A is true at Sophist College
B is false at Stoic University.
C is consistent (i.e. its true at some school).
D is contingent.
E is a contradiction.
F implies B.
[No information is supplied about G.]
For each of the following statements respond Y if the statement is correct, N if the statement is incorrect, or I if there is not enough information to decide whether or not it is correct.
- G implies ¬E.
[Answer on p 357, and online for Section 5.3 too:] 17. Y
My initial answer was I: we do not know the truth value of G or ¬E, because per the following definition, ¬E means that not every line of E's truth table is false (= ≥ 1 line is true).
[p 109:] If a wff [Well-formed Formula] is false on every line of its truth table we say it's a contradiction.
So I was stupefied to see the answer as Y.