Answer
Let p represent "I say it" and q represent "I mean it," then "I say what I mean" can be rewritten as, "if I say it, then I mean it," which is of the form p $\rightarrow$ q. The sentence "I mean what I say" can be rewritten as, "if I mean it, then I say it," which has the form q $\rightarrow$ p. Hence these two sentences are converses of each other. As was proven in problem 24, a conditional statement and its converse are not logically equivalent, so the Hatter is right.
Work Step by Step
The converse of the conditional statement p $\rightarrow$ q is q $\rightarrow$ p.
