Tuesday, April 23, 2019

Perdurance, physicalism and mind

According to standard perdurantism, we are four-dimensional beings made out of three-dimensional slices, and properties such as mental ones are primarily had by the slices, and only derivatively by the four-dimensional whole.

Here are two problems with this when conjoined with widely held views.

First, mental states are intrinsic to the entity that has them primarily. But most perdurantists are physicalists. If mental states are intrinsic and had by three-dimensional slices, then it is possible to have a world with just one such three-dimensional slice with mental properties, isolated from other slices. But a single three-dimensional slice, isolated from other slices, does not have the functonal properties that the more plausible physicalist theories of mind require.

Second, it is clearly worse if someone has a constant headache for two hours than for one hour. But if time is continuous, as is widely held, then both the one-hour headache scenario and the two-hour headache scenario have the same infinite number of aching slices that are the primary bearers of the pain. But two scenarios which have the same number of primary painbearers are equally bad. Hence, a two-hour headache is no worse than a one-hour one. Which is absurd.

The perdurantist can escape this by saying that mental states are primarily had by the four-dimensional entity, and the three-dimensional slices, if they have mental states at all, have them derivatively. There are two ways of running this story. One way is that the slices have mental* states: states that aren’t mental states but that ground mental states in the four-dimensional whole. Thus, a four-dimensional entity hurts at time t just in case its slice at t hurts, but hurting isn’t a mental state, and doesn’t have the negative significance of hurting.

A second way is to say that the mental states of the four-dimensional entity reduce to ordinary physical states (positions, shapes, momenta, charges, etc.) of multiple three-dimensional slices.

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