Why Aren’t Ghosts Blind?

Ain’t nothin’ to see here.

Ghosts are like zombies, but opposite. That’s the story in philosophy of mind, at least. Whereas zombies have all of our physical properties and none of our mental ones, ghosts have all of our mental properties and none of our physical ones. Are ghosts conceivable/possible? Before diving into that, I want to ask first: Are they blind?

René Descartes, the original ghost in the machine.

Why aren’t (philosophical) ghosts blind (and deaf, etc.)? One of my physical properties, and one that seems quite obviously important for my ability to see, is that light rays don’t just pass right through the spaces I occupy. I absorb light. With my eyes. But occupying spaces and interrupting the free passage of light are physical properties I have that my so-called ghost doppelgänger would lack. And seeing is one of the mental things I do. So maybe philosophical ghosts, which allegedly have all my mental properties and none of my physical ones, are inconceivable/impossible.

Here’s another thing it’s hard to see if you literally have no physical properties: It’s exceedingly hard to see things from one point of view as opposed to another. One might even say it’s impossible to see that if you’re totally ghostly. Embodied minds, in contrast, can occupy literal spaces with their beefy bodies and thus see these three houses from a point of view in front of the first house, and not the second, or vice-versa. See?:

Illustration from Mandik, Pete. (2001) Mental Representation and the Subjectivity of Consciousness. Philosophical Psychology 14 (2): 179-202. https://philarchive.org/archive/MANMRA

Spatial phenomenology is intrinsically structural and its explanation is due, at least in part, to physical/structural properties of perceivers and the structural properties of the things perceived. A ghost that was literally nowhere wouldn’t see the houses from the point of view that you and I do. And a ghost that is an extensionless point wouldn’t be able to see a triangle instead of a square, since all light-rays from the parts of those shapes would converge on a literal single point, thus destroying any capacity to discern different distances between the shapes’ parts. And anyway, a single point couldn’t absorb any light, and would thus be totally transparent. And totally blind.

Moral of the story: If you can see this, you aren’t a ghost: 👻.

Ok, now direct your fleshy senses further downward and please enjoy this spooky comic 👁️👁️: