"Scratch or Not" joke

This conversation took place between Mr. Kens Tar and his son Klin Ton.
Dad
Son, come in here, we need to talk.
Son
What's up, Dad?
Dad
There's a scratch down the side of the car. Did you do it?
Son
I don't believe, if I understand the definition of "scratch the car", that I can say,
truthfully, that I scratched the car.
Dad
Well, it wasn't there yesterday, and you drove the car last night, And no one else has driven it
since. How can you explain the scratch?
Son
Well, as I've said before, I have no recollection of scratching the car. While it is true that I
did take the car out last night, I did not scratch it.
Dad
But your sister, Monica, has told me she saw you back the car against the mailbox at the end of
the driveway, heard a loud scraping sound, saw you get out to examine the car, and then drive
away. So again I'll ask you, yes or no, did you scratch the car?
Son
Oh, you mean you think you have evidence to prove I scratched it. Well, you see, I understood
you to mean did "I" scratch the car. I stand by my earlier statement, that I did not scratch the
car.
Dad
Are you trying to tell me you didn't drive the car into the mailbox?
Son
Well, you see sir, I was trying to drive the car into the street. I mishandled the steering of
the car, and it resulted in direct contact with the mailbox, though that was clearly not my
intent.
Dad
So you are then saying that you did hit the mailbox?
Son
No sir, that's not my statement. I'll refer you back to my original statement that I did not
scratch the car.
Dad
But the car did hit the mailbox, and the car did get scratched as a result of this contact?
Son
Well, yes, I suppose you could look at it that way.
Dad
So you lied to me when you said you did not scratch the car?
Son
No. No, that's not correct. Your question was "Did I scratch the car?". From a strict legal
definition, as I understood the meaning of that sentence, I did not scratch the car... the
mailbox did... I was merely present when the scratching occurred. So my answer of No" when you
asked "Did I scratch the car" was legally correct, although I did not volunteer information.
Dad
Son, you are such a slick talker you're either gonna wind up as a lawyer or President....