Dylan accepts that Santa is 'metaphorical' (though he doesn't know the exact meaning of that word) as an explanation for all mysteries about the man.  ("How can Santa fit down a small chimney?" etc.)  He knows that Santa is both metaphorical and 'real' (as metaphors are real).  Maybe he thinks 'metaphorical' means 'magical'.  Daddy has told him that Santa is a metaphor for 'the spirit of Christmas'.

Music February 2013.

DADDY:  Is your name Isaac Obediah?
ISAAC:  No.  Isaac Obedylan.

Playing with Friends August 2012

Cheering Trampoline Slippers July and August 2012.

Maverick

Isaac asks us, each time we use the car, to put the 'music' on.  He knows that we press some buttons on the dashboard, in order to play the stereo.

Yesterday Isaac climbed into the cockpit of a real fighter jet, in the RAF museum.  He stared at the instrument panel, the altimeter and so forth, and said, 'Music on'.

DADDY:  What do rhinos eat?
ISAAC:  Chocolate tarts.

Dylan and Isaac making music.

DYLAN:  Do you know how many legs are on the people who live in this house?  Eight.  Do you want to know how I found out?  I counted how many legs I have, and Isaac, and you Daddy, and then I pretended Mummy was here, and I counted her legs too.