Monday, July 1, 2019

Theories of time and truth-supervenes-on-being

Truth supervenes on being is the thesis that if two worlds have the same entities, they are otherwise the same. I just realized something that should be pretty obvious. One cannot hold on to all three of the following:

  • A-theory

  • eternalism

  • truth supervenes on being.

For according to eternalism, at any two different times, the facts about what exists are the same. So if truth supervenes on being, at any two different times, all facts are the same—and in particular the facts about what time is objectively present will be the same, which contradicts A-theory.

In other words, just as the best version of presentism (that of Trenton Merricks) rejects that truth supervenes on being, so does the best version of the moving spotlight theory. Moreover, closed-future growing blockers—and, in particular, classical theist growing blockers—will also want to reject that truth supervenes on being since substantive truths about the future won’t supervene on being given growing block.

All this suggests that we are left with only two major theories of time available to those who accept that truth supervenes on being:

  • B-theoretic eternalism

  • growing block with an open future.


Red said...

Dr. Pruss, why do you think Trenton Merrick's Presentism is the best version of it? If I recall correctly your view about modality is that truths about other worlds are grounded in the actual world so why aren't you more sympathetic to the sort of presentism that grounds truths about other times in present?

Alexander R Pruss said...

It's not going to give you contingent truths about the future without supposing something like ubiquitous backwards causation.

And it's implausible with respect to the past on a substance ontology. Imagine a world where God creates a finite bunch of free creatures that live for a finite amount of time, and after they die off, there are no longer any creatures, only God. Then there are no substances to ground facts about the creatures' past activity other than God. But to ground facts about the past in God would require violations of divine immutability and simplicity.

One could suppose additional types of entities, such as contingent states of affairs, to make things true. But that's a violation of both Ockham's razor and substance ontology, and it supposes a mysterious metaphysically necessary transtemporal causation.

Michael Gonzalez said...

Just a side-point, I suppose, but don't all views where God is in time "violate divine immutability and simplicity" in this same way?