Akinbo,
"Let me put it this way. The groups 1 and 2 that try to answer the question 'what is space' are wrong in the question itself"
What specifically is wrong with the question?
Marcel: Philosophy keeps pretty much the same questions through the ages. But the answers are time sensitive. In the age of QM and GR the answer and even the questions must be adapted.
"Space is a construct of our mind and already carries dimensions"
Marcel: The universe is a cold dark place with matter and radiations. Our eyes and mind make from it the color, conceive the space and shapes etc. My questions pertain to matters behind this perception.
Are you saying that without minds space cannot exist?
Marcel: Yes. We already know that. This is why we call it space-time. It is all time, but we kept the "space" part in order to keep the experience of physics going. You look at a meter stick. That is space for you. But the universe has no eyse and mind to integrate, like you do, all the points of the meter in one moment of perception. No. The universe has no point of view like you do. The universe is not contemplative, it is operational. For one point to affect another point requires some time even at the speed of light. Because it requires time they cannot be at the same moment. On the other hand, Space is a concept of things being at the same moment, like objects ...
"What substance makes the vacuum"
Marcel: Substance it that which exist by itself, we don't make it, and it makes everything but that we cannot perceived other than through a relationship called "experience". Experience is our own adapted, transformed interpretation of the substance. All of our reality is nothing without us making it by our experience. Physics is the study of this experience.
"Metaphysics..."
My dictionary says: branch of philosophy concerned with being and knowing. Is physics not also about being and knowing?
Marcel: Yes, but within the confines of our experience. Sure, as Dean Rickles explained, a kind of metaphysics is creeping into physics with advanced mathematics and other theories. But excess baggage is carried along and we don't let go easily and enough of the way we perceive and think required to address the foundation of it all.
Answers to most other questions are in the posts to Roger.
Thanks,
Marcel,