"chuck" wrote in message
...

you can restate most negatives as positives. an example of this is a
logical statement, in which case the contrapositive is always true. if
P,
then Q. if not Q, then not P.

Afraid you have this wrong, gravity.

Consider:

P=today is my birthday
Q=I will receive a present

If (today is my birthday) then (I will
receive a present).

If (I will receive a present) then MAYBE
today is my birthday and MAYBE it is not.

that's not the contrapositive. that's the converse, i think.

Gravity