The Turn to Materialism
At the level of molecular structure the table is not really solid. It is, as the physicist Eddington said, a cloud of molecules. It is just that from our point of view it seems solid. But at bottom the physical world consists entirely of microentities, the physical particles. However, there is one exception. Consciousness is not just particles. In fact it is not particles at all. Whatever else it is, it is something “over and above” the particles. I believe this is the insight that drives contemporary property dualism.Page 33
Chapter 4 – Consciousness Part 1
Consciousness and the Mind-Body Problem
II. Solutions to the Mind-Body Problem
All forms of cosnciousness are caused by the behaviour of neurons and are realized in the brain system, which is itself composed of neurons. What goes for thirst goes for all kinds of conscious life whatever, from wanting to throw up to wondering how to translate the poems of Stéphane Mallarmé into colloquial English. All conscious states are caused by lower level neuronal processes in the brain. We have conscious thoughts and feelings; they are caused by nuerobiological proccesses in the brain; and they exist as biological features of the brain system.
I will state biological naturalism about consciousness as a set of four theses:
1. Conscious states, with their subjective, first-person ontology, are real phenomena in the real world. We cannot do an eliminative reduction of consciousness, showing that it is just an illusion. Nor can we reduce consciousness to its neurobiological basis, because such a third-person reduction would leave out the first-person ontology of consciousness.
2. Conscious states are entirely caused by lower level neurobiological processes in the brain. Conscious states are thus causally reducible to neurobiological processes. They have absolutely no life of their own, independent of the neurobiology. Causally speaking, they are not something “over and above” neurobiological processes.
3. Consious states are realized in the brain as features of the brain system, and thus exist at a level higher than that of neurons and synapses. Individual neurons are not conscious, but portions of the brain system composed of neurons are consious.
4. Because conscious states are real features of the real world, they function causally. My conscious thirst causes me to drink water for example. I wall explain in detail how this worls in chapter 7…
Page 79
III. Overcoming Mistaken Assumptions
Assumption 1. The distinction between the Mental and the Physical
The worst mistake is to suppose that the common sense distiction between mental states naïvely construed and physical states naïvely construed is an expression of some deep metaphysical distinction. On the view that I am presenting, it is not. Consciousness is a system-level, biological feature in much the same way that digestion, or growth, or the secretion of bile are system level, biological features. As such, consciousness is a feature of the brain and thus a part of the physical world. The tradition that I am militating against says that because mental states are intrisically mental, they cannot be in that very respect, physical. I am in effect saying that because they are intrinsically mental, they are a certain type of biological state, and therefore a fortiori they are physical. However, the whole terminology of mental and physical was designed to try to make an absolute opposition between the mental and the physical, so maybe it is better not to use that terminology at all and just say that consciousness is a bilogical feature of the brain in the same way that digestion is a biological feature of the digestive tract. We are in both cases talking about natural processes. There is no metaphysical gulf.
(Relates to Bohm’s idea that there is no distinction between consciousness and the world ‘outside’, also Merleau-Ponty, and also much of what Hockney has to say)
Page 81
Assumption 2. Reduction
…the main point of having the concept of consciousness is to capture the first-person, subjective features of the phenomenon and this point is lost if we redefine consciousness in third-person, objective terms. ..Consider…Beethoven’s Ninth Symphony….Performances of the Ninth Symphony can be reduced to wave motions in the air, but that is not what is interesting to us about the performance. The music critic who writes, “All I could hear were wave motions,” has missed the point of the performance. Analogously you could do a reduction of consciousness and intentionality, but you would still need a vocabulary to talk about the surface features. Consciousness and intentionality are unique only in that they have a forst-person ontology.
Page 84
…we would lose the point of having the concepts of consciousness if we carved off the first-person ontology and redefined the words in third-person terms. In that sense the irreducibility of consciousness does not reveal a deep metaphysical asymmetry between, for example, the way colour experiences relate to their causes and the way pain experiences relate to their causes, but rather an asymmetry in our definitional practices. For the definition of “pain” we care more about how pain feels to us than we do for the definition of “colour”.
Page 85
To summarize this brief discussion of reduction: you can’t do an eliminative reduction of consciousness because it really exists; and its real existence is not subject to the usual epistemic doubts, because those doubts rest on a distinction between appearance and reality and you can’t make that distinction for the very existence of your own conscious states. You can do a causal reduction of consciousness to its neuronal substrate, but that reduction does not lead to an ontological reduction because consciousness has a first-person ontology, and you lose the point of having the concept if you redefine it in third-person terms.
Page 86
Assumption 4. Identity
Is consciousness identical with the brain or not? Well, obviously and trivially, as I have said, consciousness is just a brain process. It is a qualitative, subjective, first-person process going on in the nervous system. Yes, but that is not what the identity theorists wanted. What they wanted was to indentify a conscious state with a neurobiological process, neurobiologically described. Here it seems to me we are looking for a decision and not for a discovery.
The concept of identity is not much help with the mind-body problem because we can make our events big enough to include both the phenomenological and the neurobiological. The right move, as usual, is to forget about these great categories and try to describe the facts. Then go back to see how you have to adjust the preconceptions you may have of other categories in order to accommodate the facts.
Page 87
IV. Neither Materialism Nor Dualism
It is worth emphasizing the view that I am expounding differs from both materialism and dualism. Because I think that both materialism and dualism are trying to say something true, it is important to carve off the true parts from the false parts. To do that I need to state exactly the differences between my view and the traditional views. Materialism tries to say truly that the universe is entirely made up of physical particles that exist in fields of force and are often organized into systems. But it ends up saying falsely that there are no ontologically irreducible mental phenomena. Dualism tries to say truly that there are irreducible mental phenomena. But it ends up saying falsely that these are something apart from the ordinary physical world we all live in, that they are something over and above their physical substrate.
Page 88
The fact that the causal powers of consciousness and the causal powers of its neuronal base are exactly the same shows that we are not talking about two independent things, consciousness and neuronal processes. If two things in the empirical world have an independent existence they must have different causal powers. But the causal powers of consciousness are exactly the same as those of the neuronal substrate. This situation is exactly like the causal powers of solid objects and the causal powers of their molecular constituents. We are not talking about two different entities but about the same system at different levels. Consciousness differs from solidity, liquidity, etc., in that the causal reduction does not lead to an ontological reduction. This, as we have seen, is so far an obvious, and indeed trivial, reason. Consciousness has a first-person ontology; neuronal processes have a third-person ontology. For that reason you cannot ontologically reduce the former to the latter. Consciousness is thus an aspect of the brain, the aspect that consists of ontologically subjective experiences. But there are not two metaphysical realms in your skull, one “physical” and one “mental”. Rather, there are just processes going on in your brain and some of them are conscious experiences.
Page 89
At the most fundamental level points of mass/energy are constituted by the forces that are described by the laws of nature. From these laws the existence of consciousness follows as a logical consequence, just as does the existence of any other biological phenomena, such as growth, digestion, or reproduction.
Page 90
Think of it this way: roughly speaking, consciousness is to neurons as the solidity of the piston is to the metal molecules. Both consciousness and solidity function causally. But neither is “over and above” the systems of which they are a part.
Page 91
Chapter 5
Consciousness Part II The Structure of Consciousness and Neurobiology
2. Subjectivity
Because of the qualitative character of consciousness, conscious states exist only when they are experienced by a human or animal subject. They have a type of subjectivity that I call ontological subjectivity. Another way to make this same point is to say that consciousness has a first-person ontology. It exists only as experienced by a human or animal subject and in that sense it exists only from a first-person point of view. When I know about your consciousness, I have knowledge that is quite different from the kind of knowledge I have of my own consciousness.
The fact that conscious states are ontologically subjective, in the sense that they exist only as experienced by a human or animal subject, does not imply that there cannot be a scientifically [or artistically] objective study of conscious states.
Page 94
3. Unity
At present, I do not just experience the feelings in my fingertips, the pressure of the shirt against my neck, and the sight of the falling autumn leaves outside, but I experience all of these as part of a single, unified, conscious field. Consciousness of the normal, non-pathological kind, comes to us with a unified structure. Kant called this unity of the conscious field the “transcendental unity of apperception”, and made a great deal out of it. He was right to do so…
I used to think that these three features, qualitativeness, subjectivity, and unity, could be described as three features of consciousness. It now seems to me that that is a mistake; they are all aspects of the same phenomenon. Consciousness is by its very essence qualitative, subjective, and unified. There is no way that a state could be qualitative, in the sense that I have introduced, without also being subjective in the sense that I have explained. But there is no way that the state could be both qualitative and subjective without having the kind of unity that I have been describing.
Page 95
6. The Distinction between the Center and the Periphery
Within the conscious field, one is always paying more attention to some things than others. I am, right now, concentrating my attention on writing down ideas about the philosophy of mind, and not on the sounds coming from outside, or the light streaming in through the window. Some things are at the center of my conscious field, others are at the periphery. A good mark of this is that one can shift one’s attention at will. I can focus my attention on the glass of water in front of me, or on the trees outside the window, without even altering my position, and indeed without even moving my eyes. In some sense, the conscious field remains the same, but I focus on different features of it [Perhaps not possible with one-point perspective?]. This ability to redirect attention and the distinction between those features in the conscious field that we are paying attention to, is already a subject of important research in neurobiology.
In our capacity to shift our attention at will, typically the brain plays small tricks to cover for certain deficits. We do not see our blind spot, though we do have a blind spot; and we see colour at the periphery of our visual field even though there is no colour receptivity there.
Page 98
10. The Gestalt Structure
Our conscious experiences do not just come to us as a disorganized mess; rather they typically come to us with well-defined, and sometimes even precise, structures. We do not, for example, in normal vision see undifferentiated blurs and fragments; rather, we see tables, chairs, people, cars, etc., even though only fragments of those objects are reflecting photons at the retina, and the retinal image is in various ways distorted. The Gestalt psychologists investigated these structures and found certain interesting facts. One is, the brain has a capacity to take degenerate stimuli and organize them into coherent wholes. Furthermore, it is able to take a constant stimulus and treat it now as one perception, now as another. So in the famous “duck-rabbit” example there is a constant perceptual input but I perceive it now as a duck, now as a rabbit.
 |
| Duck-Rabbit, Simon Cunningham, 2007 |
In these [examples], the left hand figure does not actually physically resemble a human face, but nonetheless, you will perceive it as a face because your brain organizes the degenerate stimulus into a coherent whole. The right hand figure is the famous duck-rabbit, which can be seen either as a duck or as a rabbit.
Furthermore, the Gestalt structure is not only a matter of organizing our perceptions into coherent wholes, but within the entire conscious field, we make a distinction between the figures that we are perceiving and the ground on which they are perceived. So, for example, I see the pen against the background of the book, the book against the background of the desk, the desk against the background of the floor, and the floor against the rest of the room, until I reach the horizon of my entire perceptual field.
Page 100
No comments:
Post a Comment