Nothing is ever «necessarily true» (in the
philosophical sense) in the
real world, (except the trivial, such as «Milliband is Milliband», and even then...) The important point is that the causal connections have not been made, ever, by anyone.
Every time I come face to face with the idea that somehow GCMs have a life of their own (literally) and are therefore of equal value as observations of the
real world, I
sense a deep
philosophical divide that goes to the heart of modern scientific method and empiricism.