QED

During recent banter with my father over email, he requsted I elaborate on a theory I doumented in a recent post. OK, elaborate isn't exactly accurate. He disagreed with my theory that the skinny people sitting around the dining room table at our holiday gatherings are all in-laws.

Without naming names, we agreed that of the 5 in-laws at the table, only two can be deemed, "skinny." Dad said, "...2 out of 5 does not bode well with your in-law theory. Go back and update your blog! Ha ha ha."

Dad, I think you are arguing the wrong point here. For the record, "...and the skinny people are all in-laws..." has an entirely different meaning than "all the in-laws are skinny," which is what you were arguing in your emails and why you have some beef with my theory. Which isn't really a theory - it's more of an observation, but whatever.

Let's discuss further...

Let's let p represent the people who are skinny.
And let's let q represent the peole who are in-laws.

My argument that the skinny people at the table are in-laws can be logically represented in terms of p and q. What I was saying, was "if p then q." If you are skinny, then you are an in-law. Dad, unfortunately, you were arguing the CONVERSE of my statement, "If q then p." In this case, the CONVERSE of my statement would be, "If you are an in-law, you are skinny." Mathematically or logically speaking, the CONVERSE of a statement is not necessarily true. And as you argued over email, it is not true as applied to our real-life family matters. So kudos, you're point was correct, but you were not correctly analyzing my argument.

Because I'm your daughter and you love me, and because I think you need this logic refresher course, I am going to keep going. The INVERSE of my statement, "If not p then not q," or for the skinny in-law scenario, "If you are not an in-law, then you are not skinny," also cannot be deduced to be logically true given my original statement. However you weren't arguing this point, so this is all fluff right now.

But - I do want to point out that the CONTRAPOSITIVE of my original statement, "If not q then not p," which In this case would be, "If you are not skinny, then you are not an in-law," actually DOES have the same logical value as my original statement itself. So if you were arguing this point, you'd be wasting your time, but you'd be right.

I'm going to wrap things up, now. (If only I could find a therefore sign on my keyboard...)

Therefore, I am still right. And you are technically right, as well, but because I'm disappointed that your argument was not entirely valid, I am going to crown myself more right than you.

There is an additional lesson for you, here, though - and it's one I think you will like. You SO got your money's worth by paying Council Rock School District taxes and then agreeing to pay 3/4 of my college education at UVA. I probably could have learned this stuff at Penn State - or even Drexel - but it was more fun down in Charlottesville.

And actually, I think I get a bonus lesson in all of this, too. Because I guess in some strange way, I miss asking you to help me with my algebra and calculus homework. Hell, I think I actually miss even HAVING that homework.

So I will pine away for some night after dinner in the future, when my little 14 year old son or daughter is attempting to solve the infamous Algebra 1 word problem about how long it will take the boat to travel up the river against the current. And I will look forward being able to say, to my child's dismay nevertheless, "It would be easier if I showed you how to do this with a derivative..."

QED!