I suppose it's because we're two different beings, and no two beings can ever know each other in this world, not altogether.
We're what the Chevalier calls 'separate entities.' I seem to understand his odd, wise talk better lately.

He said the other day: 'Lonely we come into the world, and lonely we go out of it.' That's what I mean.

It makes me shudder sometimes, that part of us which lives alone for ever.
We go running on as happy as can be, like Biribi there in the garden, and all at once we stop short at a hedge, just as he does there--a hedge just too tall to look over and with no foothold for climbing.

That's what I want so much; I want to look over the Hedge." When she spoke like this to Philip, as she sometimes did, she seemed quite unconscious that he was a listener, it was rather as if he were part of her and thinking the same thoughts.

To Philip she seemed wonderful.