HOW TIME PASSES On Conceiving Time as a Process

Time is a basic ingredient of the universe. It is the dimension of change. Change has two meanings, however. There is real change in the sense that world states differing in date also differ in structure or function; and there is temporal change in the sense that states having been future become present and then past. In physics, only real change is acknowledged. Accordingly, time in physics exclusively is the dimension of real change. In experience, real change and temporal change are unified. We cannot help assuming the viewpoint of the now when undergoing experience. That is, we experience real change by being presented one state of the world after another. It was not until the advent of relativity theory that real change and temporal change were clearly distinguished. Relativity theory denies the possibility of universal simultaneity and thus the possibility of a universal now. Without the now, there is no borderline separating past and future. Removing this borderline amounts to constructing a static universe, a universe in which the states we experience sequentially are given as one block. When given as one block, reality presents itself as assumed to appear in God's eye. In the block universe, time does not pass. In this universe, time is reduced to a dimension of extension. The block extends in four dimensions. The four-dimensional block contains all the (states of) processes of real change. It does not contain the process of temporal change, however. If one proceeds from the block universe, temporal change appears as something additional: as a process supervening on spacetime. The conjecture that temporal change supervenes on spacetime agrees with the assumption that the now is subjective. For us, as conscious beings, the now is indistinguishable from the presence of our own consciousness. Consciousness conceived as mental presence supervenes on spacetime as traditionally understood. It is, nevertheless, related to processes going on in the brain. Those are processes of real