chuck wrote:
Cecil Moore wrote:
"If I receive a present today, then today is my birthday."

Assuming no present is received today, that statement is
true by definition. :-)

Sorry, Cecil. I'm not following you on that.

Neither do a lot of other people. Here's the truth table
for an: (If A then B) = C logical statement

A B C

True True True
True False False
False True True
False False True

If the if-portion of an if/then statement is false,
then the entire statement is true, by definition.

For instance, this is a logically true statement.

If I were ever to play in the NBA, then I would be a superstar.

Since the A portion can never be true, the entire statement
is true, by definition.

In your earlier example, *both of these statements are true*
if you didn't receive a present. Only if you actually received
a present can one be true and the other false.

1. If I receive a present, it's my birthday.
2. If I receive a present, it's not my birthday.
--
73, Cecil http://www.qsl.net/w5dxp