Version: v3, Published online: 2018
Retrieved March 20, 2019, from https://www.rep.routledge.com/articles/thematic/time-metaphysics-of/v-3
Metaphysics is the part of philosophy that asks questions about the nature of reality – about what there is, and what it is like. The metaphysics of time is the part of the philosophy of time that asks questions about the nature of temporal reality. One central such question is that of whether time passes or flows, or whether it has a dynamic aspect. By this metaphysicians mean something very specific: is one time metaphysically privileged in some way, and does this metaphysical privilege move on from time to time? A-theorists answer in the affirmative, and different A-theorists offer different ways of thinking about the metaphysical privilege involved. Some say the privilege consists in being the only time that exists (presentism). On presentism, only the present exists, but which time that is changes as time passes. Other A-theorists, known as growing block theorists, say the metaphysical privilege consists in being the latest time that exists. On the growing block view, the past and the present exist, but the future does not. As time passes, new times comes into existence. Yet another version of the A-theory says that all times exist, but that one time is metaphysically privileged because it is present in an absolute sense. This version of the A-theory is known as the moving spotlight theory. Different times gain the privilege in turn by becoming the one time that is present in an absolute sense.
The A-theory is opposed by the B-theory. B-theorists take all times to exist (eternalism), but unlike moving spotlight theorists, they deny that any one time is metaphysically privileged in any way. Each time is present, but only relative to itself, not in an absolute sense. The B-theory is usefully understood by comparison with views about space. A natural view of space is that all spatial locations exist and that none is ‘here’ in an absolute sense, even though each one is ‘here’ relative to itself. The B-theory says the same about time. Thus, according to B-theorists, time is in a key respect much like space: what is past, present or future is just a matter of temporal perspective, just like what is here or over there is a matter of spatial perspective.
Modern physics is more hospitable to the B-theory than to the A-theory, while ordinary thought and experience arguably favour the A-theory. One reaction to this is to endorse the B-theory, but to ask why it is that time presents itself in ordinary thought and experience as being different from how it really is. There is a growing literature on this problem that draws on cognitive science work on time perception.
Deng, Natalja. Time, metaphysics of, 2018, doi:10.4324/9780415249126-N123-3. Routledge Encyclopedia of Philosophy, Taylor and Francis, https://www.rep.routledge.com/articles/thematic/time-metaphysics-of/v-3.
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