Ladies and Gentleman, John Searle arguing against property dualism, an excerpt from ‘Why I am not a property dualist’
I put the text here in order to start a discussion about who is right and who is wrong, on the consciousness game.
Because neither consciousness nor matter are reducible to the other, they are distinct and different phenomena in the world.. Those who believe that consciousness is reducible to matter are called materialists; those who believe that matter is reducible to consciousness are called idealists. Both are mistaken for the same reason. Both try to eliminate something that really exists in its own right and cannot be reduced to something else. Now, because both materialism and idealism are false, the only reasonable alternative is dualism. But substance dualism seems out of the question for a number of reasons. For example it cannot explain how these spiritual substances came into existence in the first place and it cannot explain how they relate to the physical world. So property dualism seems the only reasonable view of the mind-body problem. Consciousness really exists, but it is not a separate substance on its own, rather it is a property of the brain.
We can summarize property dualism in the following four propositions. The first three are statements endorsed by the property dualist, the fourth is an apparent consequence or difficulty implied by the first three:
(1) There are two mutually exclusive metaphysical categories that constitute all of empirical reality: they are physical phenomena and mental phenomena. Physical phenomena are essentially objective in the sense that they exist apart from any subjective experiences of humans or animals. Mental phenomena are subjective, in the sense that they exist only as experienced by human or animal agents.
(2) Because mental states are not reducible to neurobiological states, they are something distinct from and over and above neurobiological states. The irreducibility of the mental to the physical, of consciousness to neurobiology, is by itself sufficient proof of the distinctness of the mental, and proof that the mental is something over and above the neurobiological.
(3) Mental phenomena do not constitute separate objects or substances, but rather are features or properties of the composite entity, which is a human being or an animal. So any conscious animal, such as a human being, will have two sorts of properties, mental
properties and physical properties.
(4) The chief problem for the property dualists, given these assumptions, is how can consciousness ever function causally? There are two possibilities, neither of which seems attractive. First, let us assume, as seems reasonable, that the physical universe is causally closed. It is closed in the sense that nothing outside it, nothing non-physical, could ever have causal effects inside the physical universe. If that is so, and consciousness is not a part of the physical universe, then it seems that it must be epiphenomenal. All of our conscious life plays no role whatever in any of our behavior.
On the other hand, let us assume that the physical universe is not causally closed, that consciousness can function causally in the production of physical behavior. But this seems to lead us out of the frying pan and into the fire, because we know, for example, that when I raise my arm, there is a story to be told at the level of neuron firings, neurotransmitters and muscle contractions that is entirely sufficient to account for the movement of my arm. So if we are to suppose that consciousness also functions in the movement of my arm, then it looks like we have two distinct causal stories, neither reducible to the other; and to put the matter very briefly, my bodily movements have too many causes. We have causal overdetermination.
The property dualist has a conception of consciousness and its relation to the rest of reality that I believe is profoundly mistaken. I can best make my differences with property dualism explicit by stating how I would deal with these same issues.
(1) There are not two (or five or seven) fundamental ontological categories, rather the act of categorization itself is always interest relative. For that reason the attempt to answer such questions as, “How many fundamental metaphysical categories are there?”, as it stands, is meaningless. We live in exactly one world and there are as many different ways of dividing it as you like. In addition to electromagnetism, consciousness, and gravitational attraction, there are declines in interest rates, points scored in football games, reasons for being suspicious of quantified modal logic, and election results in Florida. Now, quick, were the election results mental or physical? And how about the points scored in a football game? Do they exist only in the mind of the scorekeeper or are they rather ultimately electronic phenomena on the scoreboard? I think these are not interesting, or even meaningful, questions. We live in one world, and it has many different types of features. My view is not “pluralism,” if that term suggests that there is a nonarbitrary, noninterest-relative principle of distinguishing the elements of the plurality. A useful distinction, for certain purposes, is to be made between the biological and the non-biological. At the most fundamental level, consciousness is a biological phenomenon in the sense that it is caused by biological processes, is itself a biological process, and interacts with other biological processes. Consciousness is a biological process like digestion, photosynthesis, or the secretion of bile. Of course, our conscious lives are shaped by our culture, but culture is itself an expression of our underlying biological capacities.
Then what about irreducibility? This is the crucial distinction between my view and property dualism. Consciousness is causally reducible to brain processes, because all the features of consciousness are accounted for causally by neurobiological processes going on in the brain, and consciousness has no causal powers of its own in addition to the causal powers of the underlying neurobiology. But in the case of consciousness, causal reducibility does not lead to ontological reducibility. From the fact that consciousness is entirely accounted for causally by neuron firings, for example, it does not follow that consciousness is nothing but neuron firings. Why not? What is the difference between consciousness and other phenomena that undergo an ontological reduction on the basis of a causal reduction, phenomena such as color and solidity? The difference is that consciousness has a first person ontology; that is, it only exists as experienced by some human or animal, and therefore, it cannot be reduced to something that has a third person ontology, something that exists independently of experiences. It is as simple as that.
But if consciousness has no causal powers in addition to its neurobiological base, then does that not imply epiphenomenalism ? No. Compare: the solidity of the piston has no causal powers in addition to its molecular base, but this does not show that solidity is epiphenomenal (Try making a piston out of butter or water).
Both materialism and dualism are trying to say something true, but they both wind up saying something false. The materialist is trying to say, truly, that the universe consists entirely of material phenomena such as physical particles in fields of force. But he ends up saying, falsely, that irreducible states of consciousness do not exist. The dualist is trying to say, truly, that ontologically irreducible states of consciousness do exist, but he ends up saying, falsely, that these are not ordinary parts of the physical world. The trick is to state the truth in each view without saying the falsehood. To do that we have to challenge the assumptions behind the traditional vocabulary. The traditional vocabulary is based on the assumption that if something is a state of consciousness in the strict sense – it is inner, qualitative, subjective, etc. – then it cannot in those very respects be physical or material. And conversely if something is physical or material then it cannot in its physical or material respects be a state of consciousness. Once you abandon the assumptions behind the traditional vocabulary it is not hard to state the truth.”