This is a conversation I had with The Tort as I was heading back to work after lunch:

Me: See you later, I will be back in a couple of hours.

TT: Okay.

Me: After I get back we will go to Grandpa's house.

TT: Okay.  I don't know when that is.

Me: I know, because you have No concept of time.

TT: No, I don't. (He says this as if he understands what "Concept" and "time" mean.)

Me: Bye, I love you.