Studying the Brain
Brain studies have proceeded apace since that clump of grey tissue in our heads was tapped as the basis of mind. First it was inspected with the naked eye, prodded and poked; then dissected and anatomized; then stained and examined under a microscope; then electrically recorded, grossly and minutely; and latterly viewed by means of MRI machines and the like. With these instruments we have developed quite a full picture of the brain’s architecture, chemistry, and mechanics—its parts, constituents, and processes. The role of human eyes has been conspicuous in this effort: by using our eyes we have learned a lot about the brain (researchers don’t tend to use smell and taste or touch and hearing). Indeed, we can think of the eye as just another instrument, along with the microscope and the electrode: the eye is the main instrument the brain uses to study itself (with its cornea, retina, fovea, etc.). Brain science is methodologically ocular. It is the eye that chiefly reveals the brain as we now know it. Even when a microscope is used the human eye is still at the epistemic center.  It would be generally agreed that the same methods will continue to be used to accumulate knowledge of the brain—and that no other method would be workable, or even desirable. The brain reveals itself exclusively to these methods: third-person observation, assorted scientific instruments, and recordings of neural activity. In particular, visual perception is the best (and only) route to knowledge of the brain. For what other comparable method is available?
But this ignores another possible avenue of discovery: introspection, i.e. knowing oneself from the inside. You might reply: but introspection reveals the mind not the brain, so it is of no use as a means of learning about the brain. This, however, assumes that the mind is not an attribute of the brain—possibly being located in a separate substance altogether. But that is wrong: the mind—consciousness—is an aspect of the brain. The brain—a physical object in space—is the bearer of mental states, there being nothing else to be their bearer. Consciousness is a brain state. This shouldn’t be controversial when correctly understood: it does not mean that consciousness is a physical state of neurons just like the physical states they are known to have by using the observational method. It may well be a state of an entirely different kind, as private and subjective as any arch-dualist might wish; but it is still a state of neurons. Neurons have these states as they have the states discovered by the observational methods described above. Electrical activity is an aspect of the brain, ultimately its neurons; conscious activity is likewise as aspect of the brain, and hence its neural constituents. This means that in knowing about the mind by means of introspection we thereby come to know about the brain: we are learning about the brain by introspecting the mind. Knowledge of mind is knowledge of brain. Note that this kind of first-person knowledge is relatively primitive methodologically: there are no microscopes, electrodes, and MRI machines here. We are using our “inner eye” nakedly, without augmentation or upgrade; so we don’t have instruments that can enhance its resolution power or reveal the fine structure of what is revealed. Still, it provides genuine knowledge of the brain—knowledge that extends beyond what can be gleaned using the first method. So we really have two methods available for studying the brain: the perception-based method mainly centered on the eye, and the introspection-based method solely based on the “inner eye”. Put differently, the brain allows both methods to be used to investigate its nature, revealing different things to each.
Let’s pause to interrogate the phrase “the inner eye”. Can it be taken literally? It might be thought unavoidably metaphorical since there is no eyeball in the brain responding to light given off by the mind. But that is a much too narrow interpretation if the concept of the visual. First, we have the concept of the mind’s eye, i.e. visual imagination: we see things with the mind’s eye as well as the body’s eye. This use of “see” is not metaphorical. Second, and connected, we use the concept of seeing far more widely than for the case of seeing by use of the eyes in the head: we are constantly seeing things that are not sensed by the eyes (a glance at the dictionary will assure you of this). We could call this “intellectual seeing” but even that does not do justice the variety of ways of seeing. In fact, in this capacious use of “see”, it appears to mean something like “perceive clearly” or “perceive as a totality”, which goes well beyond the deliverances of the body’s eyes. Indeed, the eyes don’t see at all if they don’t provide seeing in this wider sense: fragmentary and indistinct visual experience doesn’t count as genuine seeing—for nothing is perceived clearly and as a totality (“blooming, buzzing confusion”). Third, the involvement of visual cortex is relevant to the question of seeing: visual imagery involves activity in the visual (occipital) cortex, and it is not to be ruled out that employment of the “inner eye” might also recruit this part of the brain. It is noteworthy that talk of the “inner eye” (like talk of the “mind’s eye”) comes very naturally to us—we don’t likewise reach for the phrases “inner ear” or “inner touch”—and this may indicate an appreciation of the visual character of introspection. Nothing rules out the idea that introspection might have a visual character in the wide sense, and it is certainly not contrary to our habitual modes of speech. In fact, once you become accustomed to the idea, it becomes quite natural to regard introspection as a mode of seeing: it is certainly an example of perceiving things clearly and as a totality. I propose, then, to speak in this way: then we can say (what is agreeably neat) that we know about the brain by two kinds of seeing—seeing with the eyes embedded in the face and seeing with the inner eye. Both types of eye enable us to see aspects of the brain: physical and mental aspects, respectively. Thus we can study the brain by employing our two sorts of eye—outer and inner. Now we see it one way, now another, with different properties revealed, depending on the type of eye being used.
The point of central interest to me at present is that neither eye tells the full story. Actually that understates it: each eye is systematically blind to what the other eye sees. The outer eye tells us nothing about the mental aspect of the brain, and the inner eye tells us nothing about the physical aspect of the brain. Each eye is perceptually closed to what the other eye is open to—rather as the human eye is closed to certain parts of the spectrum. The outer eye reveals quite a bit about the brain but stops short where the mind begins, while the inner eye is very revealing about mental aspects of the brain but cannot extend to its physical aspects. In fact, the situation is even more extreme than that: the inner eye doesn’t even give so much as a hint that the brain is a physical object located in the head, while the outer eye intimates nothing about the existence of consciousness. So far as each eye is concerned, the brain is nothing other than what it can reveal; but each offers only a very partial picture of the brain’s full reality. These two modes of seeing are thus remarkably tunnel-visioned.  They don’t even acknowledge the existence of the aspect of the brain they are not geared to reveal. They are blind to each other’s domain in a very strong sense: constitutionally ignorant, dedicatedly blinkered. It is almost as if they want to deny that the brain has another aspect altogether—the one they can’t resonate to. And this means that, as means of studying the brain, they each suffer from what I shall call methodological closure. It could also be called methodological blindness or partiality or selectivity or divergence or tunnel vision or bias or ignorance, but I use the word “closure” to recall the phrase “cognitive closure”: the type of closure at work here derives from specifically methodological limitations rather than from limitations of the entire cognitive system. We could also call it “instrumental closure”, bearing in mind the point that methods involve instruments, whether natural or artificial. If the eye counts as an instrument of investigation, then we can say that the outer eye is instrumentally closed to mental aspects of the brain, while the inner eye is instrumentally closed to physical aspects of the brain. Both are useful instruments for gaining knowledge of some aspects of the brain but also useless for gaining knowledge of other aspects. They each suffer from a form of instrumental specialization: one is designed to get at physical aspects of the brain (inter alia) and the other is designed to get at mental aspects of the brain. The brain has each aspect just as objectively as it has the other, but our methods of knowing about it favor one aspect over the other, as a matter of their very structure. Outer eyes can vary in their scope and limits from organism to organism; well, our two sorts of eyes also vary in their scope and limits. Each has a blind spot where the other has clear vision. That’s just the way these eyes are made.
Now this raises an intriguing question: are there any other aspects of the brain that these eyes don’t see? Is there anything about the brain that they are both blind to? Surely that is very possible, since not everything about the brain will be revealed by these perceptual systems: we may need theory and inference to discover properties hidden to these two modes of perception. Of course, the perceptual foundations are likely to constrain the scope of theory and inference, but we can suppose that new properties may lurk in the brain, which belong to neither sort of perceptual faculty. In fact, I think (and have argued) that this must be so, on pain of having no account of the connection between the two aspects of the brain. But I won’t repeat that now; my point is rather that the limitations of both ways of seeing suggest that we are highly confined in our methods for knowing about the brain. If both faculties are so sharply limited, what are the chances that the conjunction of them provides total coverage? Why should the capacities of these eyes, inner and outer, exhaust the objective reality of the brain? The brain might be brimming with properties to which our two eyes are completely blind. True, the two eyes do well within their respective domains of operation, yielding impressive knowledge of the brain, but the limitations of each, as revealed by the other, suggest a good deal of methodological closure—which is to say, ignorance. The two instruments have the limitations of all instruments, given their inbuilt scope and limits; and the brain might well (almost certainly does) have aspects to which they are both incapable of responding. It is left up to reason alone to try to discover what they decline to disclose, and pure reason can only go so far without a supply of primitive data to go on. What if the brain houses a completely distinct set of properties that are not hinted at by either the inner eye or the outer eye? Then we can expect methodological roadblock, instrument failure, and cognitive collapse. At any rate, the two eyes will not themselves be up to the task of disclosing what the brain contains.
Putting that aside, what are the broader implications of seeing things this way? Phenomenology turns out to be brain science: Husserl was a brain scientist (as was Sartre and other phenomenologists). Moreover, phenomenology relies on the use of an inner eye to establish its results—it has a vision-based methodology. Psychology is also the study of the brain, even in its least neurological departments, since the mind simply is an aspect of the brain. Philosophy of mind is philosophy of the brain, for the same reason. By the same token, brain science is (partly) phenomenology, because consciousness is a property of the brain as such—not just correlated with it. Locke, Hume, and Kant (among others) were students of the brain, since “impressions” and “ideas” are states of the brain (mental states of the brain). We can even describe psychological studies as studies of the physiology of the brain, since “physiology” just means “the branch of biology concerned with the normal functions of living organisms and their parts” (OED). There is no requirement here that the functions be physical in nature (whatever quite that means): they could be irreducibly mental (and that word too has no clear meaning short of stipulation). The study of mind is a physiological study, conducted by means of the instruments available to us, both natural and artificial. The study of the brain thus includes a great many methods and disciplines, many of which are divorced from the methods adopted by what is conventionally called “brain science”. The so-called humanities are all brain science in the end—and there is nothing in the least reductive in saying that. It is just an acknowledgment that the brain is the de facto locus of the mind—where the mind happens, what bodily organ it derives from. The mind is not an aspect of the kidneys or the heart, and is not an aspect of an immaterial substance; it is an aspect of the organ we call the brain. To say that is not to reduce the mind but to expand the brain. This is why it is important to understand that introspective knowledge is knowledge of an aspect of the brain (in fact, several aspects). And it is also important to understand that the kind of knowledge contained in a neurophysiology textbook is only partialknowledge of the brain, omitting everything that can be learned about the brain by introspection—as well as by psychology and other studies of the human mind (history, literature, and science itself as a human institution). The brain is a multi-faceted thing. It is a mistake to let a single mode of access to the brain bias one’s general conception of the kind of thing the brain is. The brain is a far more remarkable entity than our untutored senses represent it as being. 
 Compare astronomy: here too the investigator must rely on the eyes and optical instruments such as the telescope. Without these devices he or she would be hopelessly stymied. And it just so happens that distant objects interact with our eyes in such a way as to permit astronomical knowledge. Thus reality and method mesh, but only just.
 Isn’t it true that any instrument, including the human sense organs, contains inbuilt biases that obstruct knowledge of anything outside their range? When you look at an object through a microscope, say, you no longer take in its macro features, focused as you are on its microstructure. If you did nothing but this your whole life, you might naturally come to think that things don’t have macro features. Similarly, telescopes elide facts of distance that are apparent to ordinary vision. The eye itself with its limited visual field gives an impression of non-existence to what lies outside of it (thus fueling idealism). All instruments of knowledge tend to suppress other knowledge, if only by occupying one’s attention: so they are not just partial but also oblivious of, and biased against, realities they can’t reveal. Don’t we have a strong impression when looking at a brain that it can’t contain consciousness? Our eyes give us a biased sense of the possibilities of the brain. From a different perspective it might seem perfectly natural for the brain to be the locus of consciousness.
 It would be different if every physical object could introspect itself, thus revealing an inner mental being as well as an outer physical being, but so far as we know this isn’t so (even for the staunchest panpsychist). The brain stands magnificently alone in its dual nature. My own suspicion is that the brain is wildly different in its objective nature from what we suspect, a complete anomaly of nature, given our standard modes of knowledge acquisition. A weak analogy: the earth is really very different from other planets in the solar system, which is what allows it to have life and mind on it. It is similar to them in many ways, but in crucial respects it is not—particularly as regards water content and temperature. Likewise, beehives and ant colonies are very different from mere aggregations of insects, exhibiting another level of organization altogether. But these are only lame analogies: the brain is special in a special way (and we don’t know what that way is). I tend to picture it in my imagination as having a completely different color from every other object.