I know because I can hear him. Occasionally we have this pipe dream
in which we ask a child to "play quietly", and even more
occasionally we get something like that. With the synergy between
James and Joel, however, things usually get rough before long.
But right now, James is in preschool. And Anna is napping. Kim is
also working. There's no one else there, and he's still making the
most noise in the house! Earlier I heard him running from one side
of the room, bumping into things on each trip. Just now he was
fighting over a toy (by himself!?). I have to keep telling myself
that there really isn't another child involved. I guess this is
what elementary report cards call "plays well by himself." One
other advantage we have is that it is usually easy to find him.