Thanks to Einstein, we know one thing about consciousness: It’s inside your head. “Inside” is meant literally here. If you’re in Dallas wearing a hat, your consciousness is in Dallas, under your hat.
In a new paper (forthcoming in Synthese) I argue that Einstein’s theory of relativity shows that qualia, the elements of subjective experience, must be in the same place as their neural correlates, the brain events constituting or immediately causing them (which scientists have not yet identified). It goes like this:
1. If something shares a time with a physical event in all reference frames, it shares that physical event’s location.
2. Qualia share times with their correlates in all reference frames.
3. Therefore, qualia share their correlates’ locations.
Einstein discovered that motion affects the times at which things happen in your reference frame, or your location in spacetime. Moving toward things makes them happen earlier. Moving away makes them happen later. These effects are significant only if you move at near the speed of light.
If we’re side by side, and you’re moving near lightspeed while I’m standing still, events ahead will happen earlier for you than for me. If lightning bolts strike ahead and behind simultaneously in my reference frame, the one ahead will strike earlier in your reference frame and the one behind will strike later. They’re in different places, so you can move toward one and away from another, making them not simultaneous for you like they are for me. But when two events happen simultaneously in the same place, it’s impossible to move toward one and away from the other. This ensures simultaneity in all reference frames.
If you’re in Dallas wearing a hat, your consciousness is in Dallas, under your hat.
There can be no delay between correlates and qualia, because correlates either cause or constitute qualia. If neural correlates of consciousness are the last causal step before nonphysical qualia, as many dualists claim, they must produce qualia simultaneously or instantaneously. That’s how all causes we observe work. Whenever causes take time to have effects, an intermediate chain of steps occupies all the time in between. Hearing a song yesterday can cause me to buy the album tomorrow, but only by affecting my brain throughout the intervening period. And if neural correlates simply are qualia, as physicalists usually claim, they’re the same and must arise at the same time.
Because there is no delay between neural correlates and qualia, they must share spatial locations. If my correlates caused qualia somewhere else, you could make my qualia occur earlier than my correlates in your reference frame by moving from my correlates toward my qualia. This would be backwards causation! Relativity never allows the causal order in one reference frame to be reversed in another. It therefore requires qualia and correlates to share locations. Qualia are with their correlates, rather than being nowhere or in a weird place.
Location-sharing may come as a surprise to dualists, who hold that qualia and neural correlates are two different things. But it helps make their theory more scientific and less magical. If qualia were nowhere or far away from their correlates, our brains would have to instantaneously cause things nowhere or far away. (If correlates are quantum-level entities, they might be able to cause things far away, but there is currently insufficient evidence for these hypotheses about correlates and quantum causation.)
Contemporary physics has found 17 types of fundamental particles in space. All these particles exert their causal force locally, rather than at a distance. Location-sharing ensures that qualia will follow the same causal rules—the laws of particle physics—as everything else in space.
Discovering the physical nature of qualia would be a great explanatory triumph. But if we can’t do it, we might have to posit dualist qualia, separate from neural correlates. Location-sharing puts qualia where science wants them, whatever their nature may be. 
Lead image: spatuletail / Shutterstock
