Time

Time is what happens between interactions rather than the medium they occur in, which follows from spacetime being the membrane formed around each interaction. If each interaction has its own spacetime, time cannot be a single container, and what remains is the relation between them. Marsh reaches this by noticing that time varies for each actor, so an interaction cannot exist exactly within a fixed spacetime and it seems more accurate to consider time as occurring between interactions. The second sentence is the speculative one and it connects to the rest of the framework. Time may be synonymous with will, since will is that which chooses and time links interactions in a direction. Time flows towards greater entropy because time links interactions and the conscious and quantum will choose greater entropy, so the arrow of time is a consequence of what wills want rather than a law they are subject to. Will creates time. Two practical observations follow. A lifetime is a struggle between a store of energy and its expenditure, and those who fill their time with interactions that expand the self and provide more animated connections gain not only from extended years but from fitting more interactions into a lifetime, which makes the quantity of life a matter of interactions rather than duration. Her account of decoupling depends on the same picture, since some who have decoupled describe moving throughout spacetime and experiencing any interaction, which is coherent only if interactions persist where they occurred.

Relational theories of time run from Leibniz, who held that time is the order of successions rather than a container, through relativity's dependence of simultaneity on the observer, to Julian Barbour's argument that time does not exist independently of change and to Carlo Rovelli's relational quantum mechanics. The thermodynamic arrow of time is standardly explained by entropy increase rather than by anything choosing it. Marsh's relational account is orthodox in its structure and heterodox in its cause, since attributing the direction of time to what wills choose is a claim physics neither requires nor supports.