Substrate dependence / independence is discussed in chapter 13. The short answer is no, I do not assume substrate dependence because substrate just doesn't need

Substrate dependence / independence is discussed in chapter 13. The short answer is no, I do not assume substrate dependence because substrate just doesn't need to be addressed given the premises. It becomes irrelevant when we start from such basic premises. Instead, the biggest unanswered question is something I call "The Temporal Gap". It would seem to be the closest thing in spirit if not letter to the question of substrate dependence / independence.