I observed once to Goethe that when a friend is with us we...

I observed once to Goethe that when a friend is with us we do not think the same of him as when he is away. He replied, "Yes! because the absent friend is yourself, and he exists only in your head; whereas the friend who is present has an individuality of his own, and moves according to laws of his own, which cannot always be in accordance with those which you form for yourself.