I am not sure what the question; ‘what is necessary for physics” means. W.V.O. Quine assented to the question of was he a physicalist, that is, did he believe anything other than physical stuff exists (and he said no). With energy and mass being convertible, the stuff of which the steady state of matter is apparent to people as embedded mass is just what is.
Paradoxically Christian theology does not require a substanceless ‘spirit’ that is the mind at all, or for a soul constructed of spirit, since a soul in some respects is simply everything that one does and thinks as a physical being during a lifetime- and I am sure that God can keep track of that information as easily as someone using ebay tech can video capture stuff and keep track of what happens during one day at some place and store the information on a terrabyte thumb drive. The question of what is God made of as Spirit isn’t answerable by anything that is substance and form in the Universe that one might refer to.
Of course the entire Universe is simply what it is and no one really knows what anything is made of ultimately- even strings and zero dimension points can’t solve that question. One can know the forms and shapes of things and how the forces and particles-waves interact, and that is a lot, yet the question of what they really are-perhaps digital information itself at some level, might never be known exhaustively.
Why would Bishop Berkeley have invented ideaism- idealism as an alternative explanation for reality, if he wasn’t Christian or a theologian as well as a philosopher- and what about St. Augustine’s concept of what time is? People should quit being insulting about Christian perspectives, or theistic perspectives concerning reality. One wouldn’t want to start lining out people like Spinoza for instance, and so many others. The entire Universe could be a thought of God’s; and every mind in it comparable to a subroutine; philosophers should have an interest inf finding truth and increasing knowledge rather than defending political popular repression.
I wrote yesterday about Kurt Godel’s incompleteness theorems concerning sets and the set of all sets. Some Christians are theologians as well as philosophers and are not antipathetic to Cantor’s trans-finite infinity paradigm concerning some infinities being greater than others. I suppose some would like to rule out relativity and infinity as mutually exclusive from Hilbert space metaphors of the verse (uni or plural/multi etc).
Ontology as a definition- everything, might preclude use of the word ‘entity’. I am not an ontology expert. Deontological abstractions from one may include ‘nouns-entities”? If one were referring to God as ‘an entity’ i don’t think that would work for me. I suppose one could use Heidegger’s language etymology meanings to track down a reason why that lexicon selection would be inadequate. Russell’s paradox was a good point. I view these matters concerning intelligence as contingent being something like humans being subroutine trying to define a much larger programs containing n kinds of subroutines, with God being more than a large A.I. program-really undefinable. Godel’s incompleteness theorems seem to reflect that inability, or work as a simile.
People noted the problems with language and means concerning philosophical issues in the mid 20th century. Russell too wrote about objects and sensation in his ‘Essay on Metaphysics’ early in that century. Quine and Strawson wrote a lot on the topic. In physics perhaps monism is more true than pluralism, since ‘objects’ are part of a unified field that has pluralistic features on the surface. People have knowledge as well as awareness- in fact that may be how intelligence evolved- with triangulation and re-enforced memory to better analysise and classify motion and ‘objects’. Objects may initially have been more of a verb experience than an ossified class of ‘nouns’. Nouns (nows) are presorted things. Knowledge of cosmology is concatenated learning. I trust Jesus Christ and God for various reasons that are not simply learning. Life is quite brief in some senses and God is good- those without faith might not experience the goodness of God so much as His incidental general provisioning of grace. Oh well, to return to just philosophical things. Sartre’s Being and Nothingness explains present awareness and perception as epistemology. I read that book pretty well, its good yet there are so may philosophical works and schools concerning subjective epistemology and perceptions- that’s what ‘PF Strawson’s ‘Individuals’ and Quine’s ‘Word and Object’ are about for example. Still, there are so many more, even the very hoary ‘Mind and It’s Place in Nature’ by C.D. Broad. Self-awareness probably differs from awareness. Then one has Cartesian rationalism, sensations, forth. Awareness exist within a unified field of physics.
There is a Christian ontology, and many don’t understand the trinity. The way God with a perfect divine economy relates to the imperfect in-the-Universe with entropy for being in time is through the Son Jesus Christ. Because of original sin- missing the mark-humanity was cast into entropy, birth, death, work. It is a sorry condition and people forget about God. They are lost and without merit. Jesus is perfect though and God sees the Son rather than the lost for those that have accepted his sacrifice. Jesus is the most remarkable individual that has lived. Look at what he said and compare that to what anyone has said before in history to that point. Morality is what people actually do regarding patterns of social behavior and ethics is how they do it, or consider it.
Humans have the original sin of being temporal and subject to willfulness, entropy and imperfection-they consume energy to sustain existence. They have biological and reproductive drives, they gather in clusters and conflict sometimes. They have imperfect knowledge and conceits. Faith in the Lord and his kingdom (the Kingdom of God) is the only way to transcend the problem of original sin that governs humanity, yet humans that are saved are still imperfect.
The Universe is like a train station and people should do the best they can while here regarding stewardship and helping or loving others. Jesus Christ was crucified though. That was the essence of human morality. Even wolf packs have a kind of morality-social behavior and ethics of who leads, follows, gets first bite on the prey etc. One may reason about everything in the Universe obviously. Isaac Newton was fairly good at that and was Christian as were so many others. One of the primary differences between the saved and those remaining lost is the different destinies when the individual’s time in-the-Universe ends.