First of, I don’t want our discussion to derail this thread, which is about @AndyWalsh’s book. Maybe it should be split off.
Here are the answers to your questions:
We hashed this out before in this thread: Several States Investigating the Catholic Church - #35 by PdotdQ
I will repeat: The word “substance” here refers to the metaphysical substance of Substance Theory, not physical substance.
Let me preface: like I said, typical Catholics including myself do not hold that the Universe is closed with respect to God’s actions in the sense that the Universe and the laws of physics was created at some point and now it just acts without a need for God’s intervention.
Now, is the universe a closed system with regard to thermodynamics? First, a few concepts from physics:
- Thermodynamically closed means a system that cannot exchange matter but can exchange energy
- The Universe is a single bubble that had gotten out of inflation, and is a subset of the Multiverse. Our Universe is roughly FLRW.
The usual notion of energy is ill-defined for the entirety of an FLRW Universe, so unless you can supply a solid definition for energy that is compatible to 2), I cannot assess whether 1) is true for the Universe.
Yes, I am familiar with Godel’s incompleteness theorems. I don’t see how it is relevant in this case. Would you mind elaborating on what you mean?