“Part of me…”
“Part of me thinks this.” “Part of me feels this way.”
But which part? Wittgenstein would say: point to it. Is it your foot? Your thumb? Your head?
Does “I think this, but also that” mean the same thing? Or maybe “I think this, but I do not want to believe it”?
I can think something without committing myself to it completely. I can test my thoughts, or weigh them. I consider them, and I enumerate what follows, without accepting the conclusions. “Part of me” hypothesizes, but the rest of me waits for the results to come back from the lab. I would not want to say that part of me “thinks on its own”, however, because then it wouldn’t be part of me. It seems that I come as a unit, and talking about “part of me” that does this or that is either useless (because, though it may be “part” of me, it is still me, and thinks as I do) or nonsense (because, if it does not think as I do, it must be someone else). There does not seem to be any middle ground.
How does parallel computing work? One signal initiates two processes. This can be a difficult thing to imagine: if the signal is the same, how does the computer know to initiate two different processes? The problem is like following directions that bring you to a fork in the road; it’s natural to think that the instructions can, at best, tell you to choose one way over the other. They cannot tell you to choose both, or to make an exact copy of yourself so that you can go down both roads simultaneously. But computers are not people walking down roads, and the problem, for them, does not exist. The decision to go down both paths at once must be made in the hardware, like a stone protruding from a waterfall, that divides one stream into two.
Is this how we can understand “part of me”–as a parallel process? I think the image of the traveller trips us up: we think, Since I am thinking this, I cannot also be thinking that. “I cannot be in two places at once.” Yet, for all the mess it makes, that thought is clearly still mine, so it must belong to some other part of me, a part with which I am less familiar at the moment. This seems to be a hopeless business: I have to imagine that I have stretched some part of me so far away as to have become unfamiliar to me without having become detached from me completely. But if we abandon the idea that I am like a traveller coming to a fork in the road, that I can only be in one mental “place” at once, and think instead that I can be more like the stream going around a rock on both sides, it seems to be less troublesome.
The image of the stream, though, is uncomfortable. We (or I, anyway) do not like to think of ourselves as splitting in two and then coming back together on the other side. That doesn’t seem to be something we can do. But why is it uncomfortable? Because we have mistaken something mental for something physical?
Do neurons compute in parallel, if they compute at all?