Barney: You can't give up now. What if I told you that you could relive that night with the exact same conversations, the exact same jokes, only this time you get her and I don't.
Marshall: That's not possible.
Barney: Oh, but it is. She has... [getting more excited] Wait for it. Here it comes. Almost there...an identical twin. Yes!
Marshall: A twin isn't the same person.
Barney: Of course, it is. What do you think "identical" means? "Ident," same. "-ical," person. Same person.