Mental Physical

1. Subjective Objective

2. First person ontology Third person ontology

3. Qualitative Quantitative

4. Intentional Nonintentional

5. Not spatially located & Spatially located &

6. Non extended in space Spatially extended

7. Not explainable by physical processes Causally explainable

by microphysical processes.

8. Incapable of acting causally on the physical Acts causally and as a system

is causally closed.

This chart embodies one of the deepest mistakes in our philosophical tradition and once you lay it out in its full nakedness you can see the mistake: the first half of the left hand column, 1-4, does not imply the second half, 5-8. Consciousness does indeed have 1-4. It is irreducibly subjective and in that sense has a first person ontology. It is qualitative in the sense that there is a qualitative feel to every conscious state. It is in many cases intrinsically intentional. But consciousness does not have features 5-8. As far as we know anything about how the world works, all such conscious states are spatially located in the brain. (Indeed with current imaging technology we are starting to discover something about their locations and spatial dimensions,) they are entirely caused by brain processes and like any other higher level feature of a physical system they are capable of functioning causally. The traditional notion of the mental, that distinguishes it from the physical, contains a serious mistake. The essence of consciousness, that it is subjective qualitative, first personal and intrinsically intentional does not prevent it from being an ordinary part of the physical world with spatial locations and extensions and cause and effect relations, just like anything else.

The first and most important step in overcoming the traditional mind-body problem is to recognize that the intrinsic features of consciousness, its subjectivity, first person ontology and intentionality do not prevent it from being a biological feature of the world and thus located spatially in the brain and caused by brain process while itself capable of acting on other brain and bodily processes. Consciousness, though irreducibly mental (features 1-4 on the left) is, in that very respect, physical (features 5-8 on the right). But because the vocabulary has become so philosophically corrupt I suggest we abandon the traditional terminology of “mental” and “physical” and just say that consciousness is a higher level biological feature of brain systems.

This is the most important objection I am going to make to the tradition in this article. The essential features of consciousness are in no way inconsistent with its biological and therefore causal part of three dimensional empirical reality.

Objection 2. Biological Naturalism cannot avoid the charge of epiphenomenalism. The physical universe is “causally closed,” and if consciousness is irreducible to the physical or material universe, then it can have no causal effects on the physical universe.

Answer to Objection 2. It is because of the mistake of accepting the dualistic categories that there even seems to be a problem about epiphenomenalism. Typically higher level features of a system, such as for example the solidity of the hammer, function causally even though the higher level feature is itself entirely caused by and realized in the system of microelements. When the hammer hits the nail, you can tell the causal story, as you would in real life, at the level of weight, solidity and velocity. Force equals mass times acceleration. But when the macro push comes to the micro shove the story could also be told at the level of the molecules and energy transfer at the molecular level. These are not two independent stories, but descriptions at different levels of one continuous causal system. No one in her right mind would say that solidity is epiphenomenal on the grounds that it has a microphysical explanation. Exactly analogously when you decide to raise your arm you can tell the story at the level of the intention and the bodily movement but you could also tell the story at the micro level, the level of neuron firings in the motor cortex and the secretion of acetylcholine at the axon end plates of the motor neurons. These are not two independent stories, but descriptions at different levels of one continuous causal system. No one who was not in the grip of the Cartesian categories would ever think there was a problem about epiphenomenalism.

Objection 3. Your account seems to be self-contradictory. Is it reductionist or not? On your account, consciousness is clearly causally reducible, because it is entirely caused by neuronal processes, and it has no causal powers beyond those of neuronal processes. But at the same time, though you grant that it is causally reducible, you deny that it is ontologically reducible. You deny that consciousness can be reduced to physical processes and you insist, like old-time dualists, that it is “something over and above” the physical or material processes.

Answer to Objection 3. Objection 3 rests on a mistake about reduction. In one crucial respect the analogy with solidity is inaccurate. Solidity can be ontologically reduced to molecular behavior and consciousness cannot be reduced to neuronal behavior. To put the point more precisely, in the case of solidity the fact that we can give a complete causal explanation of solidity in terms of micro physical processes leads us to say that solidity is nothing but a certain sort of microphysical phenomenon. Causal reduction leads to ontological reduction. But in the case of consciousness we are unwilling to make the ontological reduction. Consciousness is entirely caused by neuronal behavior, but all the same we are unwilling to say that consciousness is nothing but neuronal behavior. Why not?

In the case of solidity we do not regard the surface features—such features as how solid objects feel, that they resist pressure, that they are impenetrable by other solid objects, etc.—as essential to solidity. So we carve them off and set them on one side and redefine solidity in terms of the micro causes of the surface features. Causal reduction leads to ontological reduction by redefinition. This reduction does not show that the surface features do not exist, but it simply excludes them from the essence of solidity. Well, why could we not do that with consciousness – carve off the surface features of what conscious states feel like and redefine them in terms of their micro-causes? We could, and if we knew enough, for certain purposes, say medical purposes, we might. We could then say, “This guy is in pain, even though he does not feel it yet. The thalamocortical system definitely shows the presence of pain, though it is unfelt” Just as we can now say, “Glass is really liquid, though on the surface it looks and feels solid.” But even if we did this reduction we would still need a vocabulary to name the first person subjective qualitative features of consciousness, just as we still need a vocabulary to name the surface features of solidity. Because the whole point of having our conceptual apparatus for discussing conscious states is to describe a first person ontology, we are reluctant to carve off this ontology and redefine the notion in terms of its third person causal basis. In the case of consciousness the causal reduction does not lead to an ontological reduction by redefinition, because the redefinition would take away the point of having the concept in the first place.

In earlier writings, I said that the irreducibility of consciousness was a trivial consequence of our definitional practices. That remark was widely misunderstood, and I think the misunderstanding was probably my fault, so let me clarify it here. Grant me that consciousness exists as a first-person phenomenon in a world composed almost entirely of third-person phenomena and where, indeed, at the micro level the world is entirely constituted by third-person physical particles in fields of force. Then why is consciousness not reducible in the way that, for example, liquidity, solidity and color are reducible? Well, if you look at the reduction in the case of, let us say color, pre-theoretically, we defined color in terms of how things look. Red is defined as what looks red to normal observers under normal circumstances. That seems circular, but it is not really because red can be defined ostensively and we can give a non circular account of “normal observr”. But once we discover the causal basis of the experience of red, we can redefine the color in terms of the reflectances that typically produce that experience. We carve off the experience of red and set it on one side and redefine the concept in terms of its causal base. The causal reduction leads to an ontological reduction by redefinition, by carving off the subjective component. Now, as I argued above, we cannot really do that with consciousness without losing the point of having the concept in the first place, so the asymmetry between consciousness and color is not an asymmetry in the basic structure of the universe. On the contrary, the two cases are symmetrical. The physics of colored objects, together with our constitution, cause us to have experiences of color, and the physics of our brain together with its biological constitution cause us to have the experiences of consciousness in general. But we are willing to make the reduction in the case of color in a way that we are unwilling to make it in the case of consciousness because we would lose the point of having the concept of consciousness in a way that we do not lose the point of having the concept of color if we make the reduction. That is what I meant when I said that the irreducibility of consciousness is a trivial consequence of our definitional practices. However, this remark produced a lot of misunderstandings so it is better to withdraw it and just describe the facts.

Objection 4. You are still involved in inconsistencies. You say that consciousness is caused by brain processes. But if consciousness is really caused by brain processes, then there must really be two different things there: the brain processes as a cause, and the consciousness as an effect. And that is dualism.

Answer to Objection 4. Objection 4 rests on a mistake about causation. We have been taught by Hume that causation is always a relation between discrete events ordered in time and that every singular causal relation is always an instantiation of a universal causal regularity. Lots of causal relations are like that, but not all. Many causal forces are continuous through time. Gravity, for example. The causal explanation of why this table exerts pressure on the floor is the force of gravity, but gravity does not consist of a sequence of discrete events. And lots of causal relations are bottom up and simultaneous with the effect. For example, the causal explanation of why this table supports objects is in terms of the behavior of the microparticles, but the causal explanation of why the table supports objects is not given by first specifying one event, the molecular movements, and then a later event, the support of the object. Rather the two are simultaneous. Similarly the causal explanation of why my brain is in its present state of consciousness is in terms of, let us suppose, massive rates of synchronized neuron firings at synapses. But this does not require that, first, the brain behave in a certain way and then, later, consciousness exists, rather the conscious states are realized simultaneously with the neuron firings.

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