Feeling the Brain
You can feel your heart. It beats perceptibly in your chest. Before you ever knew what a heart was you could feel it in there. When you learned about its anatomy and physiology you had no trouble recognizing the thing you knew about before: you didn’t doubt that they were one and the same. The identity was informative, given the different modes of presentation, but it wasn’t a matter of dispute. No one argues that the organ discovered in the chest is not the organ you feel thumping when you run hard—there are no heart dualists. No one thinks the heart he feels is an immaterial substance distinct from the heart described by anatomists. The anatomist simply informs us about the nature of what we feel inside. But none of this is true of the brain: you don’t feel your brain working and recognize that the organ described by the anatomist is what you feel. You don’t have sensations of your brain as it goes about its business: you don’t feel your brain transmitting nerve impulses and regulating your bodily functions, or perceiving, thinking, and feeling. That is, you don’t feel that your brain is doing these various things—this is not the content of any cognitive or sensory state of yours. You say “I can feel my heart beating” but not “I can feel my brain transmitting” or “I can feel my brain thinking”: your brain is not an intentional object so far as ordinary experience of the body is concerned—though it can become an intentional object by external perception of the body. You can feel your heart and also see it (in principle), but you can only see your brain not feel it. Your body awareness does not extend to your brain.
It is a question whether this is true only of the brain among bodily organs. Certainly we feel most of the organs of the body, particularly the muscles (of which the heart is one). Arguably we feel the bones, which are tightly interlocked with the muscles; also the stomach and intestines. But what about the liver, the kidneys, the spleen, and the pancreas—do we feel them? We can feel pain in these organs, but in the normal course of events we don’t feel their activities. Yet we sense the presence of a congeries of organs within the abdominal area, though indistinctly. I am prepared to allow that these are objects of awareness in an attenuated sense. But the brain is in a class of its own: no pain receptors and no afferent nerves leading from itself to the sensory centers. From a phenomenological point of view, it is as if it is not there at all. If you concentrate your attention on your head and face, you can make out your nose, ears, lips, eyes, forehead, back of head, cheeks—but you can’t get any sensation of your brain. It is simply not an object of awareness. The inside of your skull is a complete phenomenological blank, a sort of proprioceptive blind spot. If you turned out to have to have an empty cranium, nothing in your experience would be thereby refuted. You feel yourself to have a heart (etc.) but you don’t feel yourself to have a brain. It’s almost as if your brain is so much dead tissue so far as your self-awareness is concerned. You know your brain is in there—you have heard about it in school and maybe seen a brain or two—but you don’t have any basic proprioceptive sense of its existence, still less its nature. There is a gap in your proprioceptive field where your brain should be.
This doesn’t seem like a necessary truth. You could have been aware of your brain (maybe Martians have elaborate brain awareness). Suppose your brain contained pain receptors as well as afferent nerves connecting it to itself. Then you would feel pain in injured parts of it (“I have a dull pain in my hippocampus”) and you would have sensory experiences as of states of your brain, e.g. feeling that your occipital lobes are unusually active, or that the nerve impulses in your hypothalamus are sluggish. You might sense your brain’s gross anatomy, or the rate of cerebral blood flow. Just as you now say, “My heart is beating fast” you would say, “My brain is in a state of high excitation”. For some reason, evolution saw fit to keep us in proprioceptive ignorance of our brains—nearly all animals have no knowledge of their brain at all, though they sense their other bodily organs—but that seems like a contingent fact; we could have had basic first-person knowledge of our brains. Instead of coming up blank in the search for proprioceptive awareness of the brain, we might have had it at the forefront of our attention, a vivid pulsing presence in our phenomenal field. As it is, however, the contents of our cranium are hidden from self-awareness. Things would be different if the brain were a muscle. To be sure, we experience the effects of the brain, physical and mental, but the origin of these effects is omitted from awareness. We only sense the brain when we open the head and see it skulking in there, like a tortoise without its shell. It comes as a startling discovery, like discovering a new continent, not the ratification of what we earlier observed from the inside. We didn’t see thatcoming.
If we did sense our brain that would change the way we greet the discovery of it by external means. We would respond by saying, “Ah, so that’s what you look like, just as I pictured you (but I’m surprised at all the ridges)”. Our experience would have anticipated our discovery: we would be ready to accept that what we experienced before just is that thing now before our eyes. We knew about our brain’s existence from the inside and now we know about it from the outside—two modes of presentation of the same entity. As things stand, however, we greet the brain with something like incredulity: who would have thought that was lurking in there! We feel alienated from it, as if it is more like an intruder than an old friend. Hence our attitude to our brain differs markedly from our attitude to our other bodily organs (most if not all). And given the centrality of the brain to our own identity, this must seem like a remarkable discovery, and not a very welcome one. We had no idea what the organ of the self was like, nor even that there was such an organ sitting in our head, but now we see that it is thisunprepossessing thing. We are not disappointed by the heart, whose objective nature is close to how we anticipated it to be; but the brain strikes us as both unheralded and bathetic. If we had prior proprioceptive knowledge of it, we would have been prepared for the reality: an elevated (and erroneous) view of ourselves would have been preempted.
Someone might say that we are acquainted with our brain because we are acquainted with our mind, and the mind is just an aspect of the brain. As we feel our heart beating, so we feel our brain thinking. That is not a fatuous thought–indeed, it might even be true—but it doesn’t restore the analogy to the heart. For we don’t experience the fact that our brain thinks: maybe it does, and maybe we experience the thinking, but it doesn’t follow—and it isn’t true—that we have experiences as of our brain thinking. We don’t take our brain as an intentional object and attribute to it the property of thinking; it may have that property, but we don’t experience it as having it (we don’t experience it at all). By contrast, the heart has the property of beating and we experience it as having that property—we attribute that property to the organ in question. That is, we don’t, in thinking, attribute thinking to the brain that enables thinking. We just have the thoughts without predicating them of the brain. So our cognitive relation to the brain is quite different from our cognitive relation to the heart, even if thinking is a property of the brain that we are aware of. The thoughts are possible intentional objects, but the brain in which (allegedly) they exist is not (for us). So the brain maintains its peculiar status as a phenomenal blank: it never comes into view except as an object of external perception. It is not a felt reality of the body. It is the basis of all inner feeling, but it is not an object of inner feeling. We are aware of our nature as a muscular being, because of primitive self-awareness, but we are not similarly aware of our nature as a neural being; yet we are at least as much neural as muscular. We might never have known of the brain’s existence but that heads occasionally pop open to reveal it. And doesn’t that adventitious knowledge change our feelings about ourselves? It reveals something quite unexpected. What if we had never discovered it?