I know that totally sounds like the response should be, 'no kidding'. And that's kind of true. It's not like he hasn't known for years that we don't always want the same things (with many, many time outs to support that hypothesis), or that we don't hold the same opinions or enjoy the same stuff.
This ability is apparently called Folk Psychology, which isn't quite as condescending as it sounds. It refers to the ability most humans gain by age 3 or 4, of interpreting others' mental states. More importantly, it also refers to the ability of most humans to recognize that others have mental states.
All babies and toddlers are selfish little fucks. They have to be since they can't meet their own needs, let alone anyone else's. Sure, that baby might hand you her semi-masticated goldfish crackers, but that's because she wants you to take them, not because she wants you to have them. Nothing a pre-kindergarten kid does is personal, no matter how infuriating. It can't be, because they literally can't care less.
And then they get older (::cough thank God cough::), and roughly a million time-outs later they understand that, whoa, you're not the same person.
But there's understanding, and then there's understanding, and the latter is what hit my kid like a ton of bricks the other night. He told me it even made his hands shake, that's how big a deal it was to him. He realized, on a level he never had before, that mommy had: "a mind in your own body", to quote the way he said it.
He'd known for years that I wasn't him, but on Sunday he figured out that I'm a separate, unique individual, just as much as he is. A small distinction that's also astonishingly huge at the same time.
The funny thing is, I got hit by the same ton of bricks when he was a baby, when I really got it that this little guy had his own agenda (yes, I used the word 'agenda', like we were superpowers in a spy movie). An agenda that was completely different from mine. He'd grown inside me, but he wasn't me. And sure, I'd known that, but I didn't know it--until I suddenly did. And now nine years later, he's just figured out the same thing.
And yes, I love the irony about having that in common. ;)
The picture is 'Baby Girl Playing Toy' by Tratong at Free Digital Photos.net