Tuesday, May 31, 2016

Relativity, simultaneity, minds and brains

This is very much a thinking-in-progress post rather than a finished argument. But I've been toying with this line of thought:

  1. The simultaneity relations between conscious mental states of an ordinary human (e.g., "itching while feeling cold") are not relative to reference frame.
  2. The simultaneity relations of spatially extended states of an object are relative to a reference frame.
  3. If conscious mental states are identical with or wholly constituted by brain states, then they are spatially extended states.
  4. So, conscious mental states of an ordinary human are neither identical with nor wholly constituted by brain states.
The restriction to ordinary people rules out cases where someone has two or more centers of consciousness at a given time (e.g., due to brain-splitting, time travel, or multiple personalities). In the case of such a non-ordinary person, we can run the argument for each center of consciousness and conclude that the center's states are not identical with or constituted by brain states.

What makes this argument tricky—and this is the part I need think more about—is that of course the relativistic effects between different bits of the brain are practically negligible. The kind of time difference that would be involved in trying to see whether I started itching before starting to feel cold or whether it was the other way around would be so minuscule that I couldn't tell the difference as to which state started earlier or whether they started simultaneously. Nonetheless, there is some plausibility in thinking that there is a fact of the matter as to which state started earlier or whether they started simultaneously. Moreover, maybe we could imagine beings with bigger and faster brains where the effects would be real--and (1) plausibly isn't just a fact about us, but about any discursive agents with a single center of consciousness.

Here's an interesting thing. Suppose that one responds to the argument by saying that there is an absolute reference frame, despite relativity theory, much as defenders of the A-theory of time hold. That response doesn't get one completely out of the argument. We can argue: the absolute frame is insignificant for physics; yet it is significant for mind; so mind doesn't reduce to physics.

I also think the argument (though perhaps not the absolute-frame variant) may lead to some problems for supervenience theories of mind. But that's for future research.

13 comments:

Michael Gonzalez said...

I'm confused. If a particle both possesses a spin of "up" and a positive charge, it has both of these states simultaneously without reference to intertial frames. It is not my understanding even of the usual interpretation of STR that it dictates state of the very same object should not be simultaneous with each other....

Alexander R Pruss said...

The brain is an extended object, about 15 cm in size. The problem comes from its being extended and its states being extended spatially as well.

Michael Gonzalez said...

Fair enough. Quick question: Can't you get the same result much more cheaply (without the baggage of STR) by just showing that "states" are not the sorts of things to which positions can properly be ascribed (any more than colors can properly be ascribed to numbers)? I mean, forget conscious states; the state of a car being "in good working order" is not located somewhere. It isn't a thing so as to have location. Likewise for ANY state, conscious or otherwise. Even the brain's "state" does not have a location. The brain (an object) has a location, and happens to be in a state (which is just to say that certain collections of statements about it are now true).

Alexander R Pruss said...

We can say something about the location of a state. If the state is constituted by the properties of particles then the state is located where the particles are. The state of the car being in good working order is presumably located where the car is, and includes all the locations where parts relevant to good working order are.

Michael Gonzalez said...

That just seems like a huge mistake to me. It's like saying that the capacity of an ax to split wood is located somewhere. Besides, in what sense could a state ever be "constituted by the properties of particles"?? It could be that a composite object is in the state it is in due to the fact that it is composed of certain particles which are themselves in particular states. But a state is not an object itself; certainly not a composite object "constituted" of smaller objects.

It seems to me that a lot of the biggest problems in discussions of consciousness revolve around this sort of confusion. It's like asking where is the state of a quarter's being worth 25 cents "located"? It's just the wrong kind of question, I think.

entirelyuseless said...

"Nonetheless, there is some plausibility in thinking that there is a fact of the matter as to which state started earlier or whether they started simultaneously."

That could be true even if those states are physical states, if they involve the same parts of matter, just as there is a fact of the matter concerning whether something started to jiggle left and right before it started to jiggle up and down. That is true even according to relativity, and this is a sufficient explanation for the whole issue.

Even apart from this, however, if your argument worked, it would show that irrational animals have immaterial souls, which most people would not be willing to admit.

Alexander R Pruss said...

Excellent point about states of matter. Of course that only works basically if the two states occur in the same chunk of matter (or more generally two chunks with the same convex hull). Is this likely to happen in the brain for, say, auditory and visual perception?

As for animals, as an Aristotelian, I think all substances have an immaterial form, and in the case of animals we call that form "soul".

IanS said...

Maybe simultaneity between our conscious mental states is vague. Conventional wisdom has it that our mental states don’t change much in 1/10 sec. I recall an experiment in which people listening to speech could not say in which syllable a pop was heard (sorry, I don’t have a reference). Maybe within the limit of vagueness, there is no fact of the matter as to which conscious state came first.

In 1/10 sec, light can travel 300,000/10 = 30,000km. This is larger than our brain size by a factor of more than a million. We are very far from any relativistic limit. The speed of nerve impulses is a much tighter constraint. But maybe for hypothetical beings with very big, fast brains, the speed of light might indeed impose a limit on the temporal resolution of consciousness.

From a different angle, are we really conscious of different things simultaneously? Maybe we focus on the itch, then on the cold, then back to the itch, and interpret this as simultaneity.

entirelyuseless said...

Consciousness is not the substantial form of a thing, since things that can be conscious are not always conscious. And (it seems to me) most Aristotelians think that accidental states of a non-rational animal are spatially extended, since they think there is a difference between the way the human soul is immaterial and the souls of other animals. If I am right about that, then most Aristotelians will disagree with your argument.

According to Aristotle, you perceive things like "itching while feeling cold" using a single organ, the one he calls the "common sense." If this is the case, then you could never perceive such relations without it depending on states of the same matter (the matter of your common sense.)

Michael Gonzalez said...

entirelyuseless...

I still think the spirit of Aristotle's point (no pun intended) is being missed here. Aristotle would say that perception is part of a set of capacities that animals have. Capacities are not located. An animal uses its capacity to detect coldness (ambient or of an object) just as an ax uses its capacity to split wood. These capacities are neither material NOR non-material. It's just the wrong way to talk about them entirely. It's like asking about the color of numbers; they are neither colored NOR uncolored. It's just nonsense to ask that question at all.

Likewise, mental states are not located, they describe an exercise of capacities on the part of the whole animal. Assigning those to parts of the brain is not only experimentally disconfirmed (see Alva Noe's book "Out of Our Heads") but also conceptually confused. A piece of the brain may be causally implicated in the animal's exercise of certain capacities that it has, but that is nothing like saying that that piece of brain tissue has those capacities itself. As Peter Hacker would put it: the aeroplane cannot fly without its engine, but it's the aeroplane that flies; not the engine.

So, even without opening the can of worms about STR's proper interpretation (I'm strongly persuaded by Neo-Lorentzian approaches, myself), we have a serious (indeed, fatal) problem in the phrasing of questions such as these.

Alexander R Pruss said...

Ian:

I have a hard time seeing how it could be vague whether one experience preceded another, but then vagueness puzzles me very much anyway...

IanS said...

Well, I’m way out of my depth, but that’s never stopped me before...

Suppose I see a flash, hear a bang and feel a pinprick, not necessarily in that order. Which did I experience first? If they happened more than a few seconds apart, I have no trouble telling. What if they happened within a second? I have no trouble with the flash and the bang, but I’m not so sure about the pinprick. Pain tends to build up slowly, so it’s hard to know for sure when it began. What if they happened within 1/100 of a second? Now I surely can’t tell which I experienced first. And 1/100 of a second is still way too long for relativistic effects to be relevant.

Michael Gonzalez said...

Pruss:

To return to your original argument, what about the quantum state of two entangled particles? It seems rather clear that changes in the one are simultaneous with changes in the other, utterly regardless of reference frame. The wave-function, obviously, is not a spatially extended thing; but it is supposed to be related to the quantum state (which certainly IS a physical, spatially extended thing). So, if wave-function collapse is genuinely instantaneous, with no reference to inertial frames, and it correlates to changes in the quantum state of two entangled particles, then the instantaneity and simultaneity is present also in the state of the particles, regardless of frames.

The answer, typically, has been to use NON-relativistic quantum mechanics until we figure out how to work around this (though, technically, "flashy GRW" is a perfectly relativistic AND non-local theory). Analogously, the answer to your question may be, not to deny that conscious states are brain states (though I certainly do deny that on other grounds), but rather to throw relativity out again, just as we do in QM.