Well we know at least some of what the mind does.
How?
The best we can manage with minds is that we know how it seems to us. That's not inerrancy, merely indefeasibility. Sadly, that indefeasibility cuts both ways and so we have literally no criterion against which we can judge any mental phenomenon from the inside. There is the real problem verifying any mental event is, to quote the bard, 'like buying another copy of the paper to check that the first copy is correct. Have a go: imagine a line exactly six inches long. Now I don't deny that it seems to be six inches long and no one can gainsay you on how it seems. However, how do you verify that the line you have imagined is six inches long? You could, if you wished, imagine a ruler and imagine measuring the line and so on.
I hope you see the problem.
Now that problem gets worse.
We have a sodding great blindspot and we never notice it. Even when we follow well known techniques to expose it, we notice that something disappears, but the blindspot remains resolutely hidden behind a clear conscious experience. Now, it happens that the easy problem of consciousness comes to our aid here: there can't be any information because there are no detectors of any sort where the nerve travels into the eye. For a long time people assumed that the brain 'filled in' the blindspot, but now we know that it doesn't. It's a clear example of what psychologists call neglect. There's no signal from the world so the brain, parsimonious as ever, simply doesn't bother putting any resources there. You don't notice the blindspot because there's nothing there to detect it. The end. However, the worrying thing is that this neglect is experienced as more of the same.
Likewise, the only area of high quality vision is about the same size as the blindspot. All the rest is incredibly out of focus movement detection using huge coalitions of neurons to pull a little information out of not much. Again there are techniques to unmask this. Once again, even as you are realising that you can't tell what suit, or even colour, a card is when held almost directly in front of you, you have the image of perfectly good peripheral vision.
There's a user illusion. The assumption that this user illusion cannot be doubted is a claim that Descartes made that still, today, is intuitively obvious to most non specialists. However, up until fifty odd years ago so was the appeal to dualism and the mind being better known than the body. Up until a century or so ago the idea that God was an intuitive certainty was widespread and so on.
The problem is that what Descartes is doing with his doubting is a bit worrying. He's doubting in language, in an intentional idiom. That's the sort of thing an AI system can do. How convincing would you find an AI system coming out with descartes' formulation, quite independently and without invoking any conscious experience, merely intentional production - no first person, just words? How convincing is that? Because that's basically Dennett's position on what we do and, while I don't buy it myself,
for other reasons, I see the deep force of it and how very inadequate any response I have ever seen to it has been.
It's just been shrugged off, not refuted. He's got a profound point that whatever consciousness is, it isn't what we intuitively think it is. Dennett's spent a long time looking at what happens when brains go wrong and using that to get insight on when they don't. There's some fucking odd phenomena out there, including people who actually and sincerely claim that it is not like anything to be them. What if they are actually seeing things as they are?
