God, our genes, our environment, or some stupid programmer keying in code at an ancient terminal - there's no way free will can ever exist if we as individuals are the result of some external cause.
The interval between a cold expectation and a warm desire may be filled by expectations of varying degrees of warmth or by desires of varying degrees of coldness.
I think that one of Tim's great qualities and abilities is in what seems like a thumbnail sketch to get something quite telling, very simply, when you're doing it or being in that thumbnail sketch, you don't feel that it's important.