My belief about the nature of reality is that the only “thing” that exists is matter. That is, there is no soul, no heaven and no hell. Effects aren’t caused without an interaction with different pieces of matter, and consciousness exists within the confines of the physical head that gives rise to it.

However, although I used to be extremely firm in this position, now I am less sure, because of one question. I don’t know how to answer this from a materialist perspective. Maybe there’s just a really simple answer that I’m missing, but I’ve spoken to many people on this and no one has given it to me. Maybe you can. So here’s the question.

Where is the cat?

“HAHAHA puny humans you will never find me. (Photo by Tambako the Jaguar

I can make a picture of a cat in my head; I can close my mind and think of it. So I’m perceiving this image of a cat.

Where is the image? Where is the cat?

I first heard this question (well, I added the cat part myself) in a lecture on the mind/body problem, and my initial answer is that the cat is simply a 1:1 correlate of certain neurological activity in the brain. That is, if you open up my head you won’t see a picture of a cat, but you’d see something that’s the equivalent of it, sort of like the dots and dashes of Morse code are not English characters, but they are equivalents of them. From a materialistic perspective, you’d theoretically be able to interpret the activity in my brain through some technology, and recreate the image of the cat that I am picturing on a screen.

In fact, we’re past theorising on this, as a famous experiment last year that was widely reported as “Mind Reading” in the media demonstrated. Here’s what they did:

1) Measured brain activity as someone watched a load of YouTube videos
2) Linked up the brain imaging data with the image on the screen, creating a sort of database whereby such-and-such brain activity relates to, say, a red object in the middle of the screen, such-and-such relates to certain shape moving to the left, and so on. I’m probably over-simplifying, but that’s the gist.
3) Get the same person to watch a new set of YouTube videos, again while in the scanner measuring brain activity.
4) Use the database created in step 2 to predict what the person was seeing in step 3.

Here’s how the reconstructions compared to the original videos:

It’s important to note that the brain may not code imagined images in the same way as those you see with your own eyes, and also that each person’s brain will likely code the image of the cat in different ways (hence the need for steps 1 and 2), but, since all of the activity of the mind is thought to have a direct neural correlate, the principle is the same.

So when I was asked “where” my mental image of the cat is, that’s why I responded in this way — the image is located in the brain – it’s just in a different format.

But really, I’m not satisfied with that answer. Because in my mind I can see (well maybe not see, but certainly perceive) the cat; not the equivalent neural ‘code’, but the actual cat. I know where the neural code is, but I don’t know where the cat is.

I can’t think how the materialistic model can explain where the cat is. Doesn’t this mean then that there’s more to reality than the purely materialistic? That the materialistic model is incomplete? What am I missing?

To use a computer analogy, the words you are reading now (hello!) are represented in a chip in a computer as a string of 0’s and 1’s. That’s like the neural code in your brain. But the actual words are represented on the screen in front of your eyes. What’s the equivalent of the screen in the case of the cat? Where is it?

I’m actually asking this to you – do you know where the cat is? Am I making a simple mistake? Please leave a comment and help me out!

Where is reality?

That’s probably enough for one day, but just to take this one step further; we know that what we see is not the world. The image we see is a mental construction of the world, and psychology has identified numerous examples of how we each see the world a little differently. An obvious example is colour-blindedness. Since the brain is constructing the world we see around us, and if we assume that the neural code and the image are different things… where is reality?

Ref:

Nishimoto S, Vu AT, Naselaris T, Benjamini Y, Yu B, & Gallant JL (2011). Reconstructing visual experiences from brain activity evoked by natural movies. Current biology : CB, 21 (19), 1641-6 PMID: 21945275