Hi, after some PM discussion that went into this direction and a short check, I want to persent here a summary of some of the ideas involved concerning a link between the consciously experienced subjective world and physics. First of all, it is probably interesting to find out the controversy between "materialism" (which states that the physical world includes whatever is "consciousness") and "dualism" which is supported by some arguments that the physical world can never entirely explain all aspects of consciousness. A summary of the concepts involved can be found here: http://www.iep.utm.edu/c/consciou.htm What I will write here subscribes in a way to the dualist notion, where consciousness is something extra-physical. However, it finds its roots in the physical world. My point was the following: modern theories of physics (GR and QM) need a non-trivial relationship between the physical ontology (corresponding to a mathematical object in the theory) and the subjective experience by consciousness. This is in contrast to the Newtonian frame where a much more evident 1-1 relation can be seen. In order for this to make sense of course, some form of a dualistic vision on consciousness is necessary because a purely materialistic view cannot do. But first, what about the Newtonian frame ? In the newtonian frame, one can (almost) keep a purely materialist vision, if one associates consciousness to a physical structure (say a brain), because it is possible, because of the *physically ontologically meaningful concept of universal time* to recognise an ontologically existing 3-dim space with a brain state, which will then evolve according to that other, ontologically existing universal quantity, time, which "ticks away". Of course, in a deterministic Newtonian frame, it is always possible to construct a 4-dimensional "static" manifold, and as such to attach an ontology to a 'spacetime'. This remark is sometimes made, that there is no fundamental difference between the 4-dim static manifold in Newtonian physics, and in relativity. However, the point is that this 4-dim manifold in Newtonian physics is entirely facultative. We don't NEED the concept of a 4-dim manifold as an ontological reality in Newtonian physics. What happens in GR ? There, the postulated ontology is a static 4-dimensional manifold. We now NEED this structure, it is not facultative anymore. GR has no real meaning without the concept of a 4-dim manifold. So "yesterday" and "tomorrow" are different regions of that manifold (and even only make sense with respect to a specific world line). Yesterday exists no less than tomorrow or today. Nevertheless, we are consciously ONLY aware of "today". So I argued that you need AN EXTRA POSTULATE which maps, in a non-trivial way, the entire "state of the brain" which is a 4-dimensional structure (the worldline of the brain) onto ONLY ONE SLICE corresponding to "now" and that slice is what is subjectively experienced by the consciousness that is conjugated to that brain. Although that brain's birth still exists somewhere on the manifold, and its death too, the consciousness of the brain only experiences ONE slice of it, namely the "today" slice. And as there is NO ontologically existing universal time parameter anymore, "ticking away", there is no PHYSICAL way to select this timeslice. This has hence to be done by a non-trivial mapping from the physical ontology (4-dim structure) to the subjective experience of a conscious being. However, this is often not explicitly stated, because locally the equations LOOK like those of a Newtonian observer, with his space and time coordinates. Nevertheless, the time coordinate is now just that: a coordinate. It is not a physically existing quantity anymore that has a specific value (and hence determines a specific slice). In Newtonian physics, one could claim that only ONE value of the time parameter "had ontological existance" (and that yesterday and tomorrow did not exist). This is not possible anymore in relativity. Next comes in quantum theory. A popular (although not (yet?) standard) view on quantum theory is the relative state (or many worlds) interpretation, which claims essentially that ONLY ONE TERM in the cosmic wavefunction is consciously experienced by a conscious being - which explains the apparent probabilistic nature of QM. Usually, this meets a lot of critique because "introducing consciousness in a physical theory is somehow a bad idea". But I wanted to argue that *this was already the case when we took up general relativity with its spacetime manifold*.