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Phenomenal Consciousness and the Cause of Qualia
Phenomenal Consciousness and the Cause of Qualia
In my previous post I wrote about consciousness, specifically the beliefs that people commonly have about consciousness and my own personal findings that I have come to through introspection and reflection. I concluded that my experience of seeing, hearing, thinking, feeling, etc. always has some qualitative aspect (A.K.A. qualia) that is not reducible to anything physical/material, which means that I believe in what is known as phenomenal consciousness. It is part of the so-called “hard problem of consciousness” to figure out what makes qualia possible and how this relates to the physical body, including the brain.
When applying the concept of qualia to what is known from science, many difficulties arise. If one accepts that qualia are distinct from material substance and that therefore phenomenal consciousness is entirely distinct from any other form of consciousness, then this invites a host of difficult questions that are part of the hard problem of consciousness. Today I will consider what can be called the “Cause of Qualia Problem”: If phenomenal consciousness is qualitatively different from anything material, and therefore is not ontologically reducible to anything going on in the physical body, then how does one’s body causally affect the qualia that one experiences? What bodily states or events cause qualia to exist?
There have been numerous theories proposed regarding the Cause of Qualia Problem. Both John Searle and David Chalmers are in the camp of philosophers who believe that phenomenal consciousness is ontologically distinct from anything physical, but they have different ideas regarding the relation between the physical body and qualia. Searle advocates what he calls “biological naturalism”, in which conscious states are entirely caused by lower level neurobiological processes in the brain and are features of the brain system. Searle believes that conscious states cause qualia to exist.
Searle insists that his theory is not dualist, but he gives too strict of a definition of dualism. Since Searle has concluded that conscious states are not reducible to anything material, this makes his theory of biological naturalism a dualist theory. Note that a dualist theory can include more than just two categories of existence. At the least, a dualist theory has to include material substance and another category of existence that is, in practice at least, only knowable subjectively (with the potential for intersubjectivity to be formed). A dualist theory can include any number of ontologically distinct categories of material substance and other physical categories and also any number of ontologically distinct nonphysical categories of being.
Chalmers has a similar theory to Searle's for reconciling phenomenal consciousness with the physical world, which he calls “property dualism”. In this theory, conscious properties naturally supervene on the physical properties of the body, which is the same as saying that the physical properties of the body directly cause the properties of phenomenal consciousness. To expand on this, if property dualism is true then when a person sees something, what happens is that first the physical brain perceives the image and then this causes nonphysical qualia to exist. Chalmers also speculates that conscious properties might emerge any time a physical thing stores information about another physical thing, which can take the form of a body having information about what it sees and hears, or even a thermostat having information about the temperature of a room.
Searle's and Chalmers' dualist theories seem to provide partial theories regarding the cause of qualia. There are multiple theories that attempt to provide more detailed answers to this problem. A good place to start is to to analyze the nature of mental identity, which itself has multiple theories. Mental identity theories are those that try to answer the questions of what are mental events, mental states, and mental properties. Specifically, what is thought, perception, sensation, memory, emotion, will, and imagination? Just as there are multiple theories of mental identity, each of these theories can be extended to facilitate some form of dualism, which should provide possible answers to the Cause of Qualia Problem.
Token identity theory, which is the simplest and least generalizable of the mental identity theories, says that each mental event can be defined as a specific event within one's brain at a given time. This theory says a mental event cannot be generalized beyond the identification of any specific brain event within a specific person. So for any group of mental events that seem similar and are referred to using the same word like pain, thought, vision, etc., there is nothing universalizable across all instances of this so-called type of mental event. For example, when I have pain in different parts of my body at different times and another person also has pains at different places and at different times, there is supposedly nothing about all of these instances of pain that are similar, aside from the trivial fact that they are referred to with the same word. There might be something physically or mentally similar between any two instances of pain, but there are no essential properties that the word “pain” actually refers to. Each one simply stands on its own, despite the fact that we try to use the same word to refer to all of them.
Donald Davidson formulated a materialist version of this called anomalous monism. This is a monist theory because it holds that mental events are identical with physical events and that no nonphysical properties or categories exist. Anomalous dualism is similar to anomalous monism but adds a dualist element. This theory says that any time a mental event occurs, this causes a single instance of qualia to exist. An implication of anomalous dualism is that there is no law of nature through which qualia are caused to exist by certain types of brain events. It would seem, therefore, that each instance of qualia would end up being a supernatural occurrence.
Type identity theory says that mental events are more generally identified by the type of events in the brain. The idea behind this is that each type of mental event, such as pain, pleasure, memory, etc. have some type of brain event that is the same for all beings that have mental events. For example, if modern science has identified certain brain events, such as C-fiber firings, as being responsible for sensations of pain, then this type of C-fiber firings is exactly what one is referring to when they speak of pain.
The monist version of this theory, which identifies mental types with physical types and holds that no nonphysical properties or categories of being exist, is called type physicalism. Type identity theory can also be extended to facilitate dualism if one assumes that the brain events that identify mental events can also be what causes certain types of qualia to exist. This version of dualism, which I will call type parallelism, would then in turn hold that any time a C-fiber fires in one's brain that an associated type of qualia are caused to exist and the same is true for all other types of brain events. Unlike anomalous dualism, type parallelism can be explained in terms of hypothesized laws of nature and therefore is naturalizable.
Both anomalous dualism and type parallelism seem to be able to provide a plausible answer to the Cause of Qualia Problem, but they both have problems. As Saul Kripke has pointed out, it appears that there are many species of living creatures that feel pain and that have memories, but if type identity theory were true then in order for a species to have genuine mental events, it must have exactly the same type of brain events as humans do. This is unlikely to be the case, so the dualist extension of type identity theory might restrict qualia to humans alone or at least to animals that have very similar brain functions as humans.
Another theory, called functionalism, identifies mental events not by any specific physical implementation but by the function that is performed. For example, many animals seem to have the ability to feel pain, so the definition of pain can be generalized to describe what is going on functionally when a being is in pain. This can be something along the lines of “any internal sensory input that is intended to inform a being that its body is being damaged in some way”. This kind of knowledge is essential for most, if not all, living beings. Also, since computers are usually thought to have memory of their own, the definition of memory can also be generalized to describe what is going on functionally when either a living being or a computer has memory.
Like type and token identity theories, functionalism also has monist and dualist variations. Functional physicalism identifies mental events with the functions of systems that have a purely physical implementation and also denies that anything nonphysical exists. The theory of functionalism can also be extended to facilitate dualism if one assumes that the functional operations of a living being or a machine can cause certain types of qualia to exist. Under this theory, which can be called functional parallelism, if there are qualia associated with pain, then an instance of qualia would be caused to exist any time a human is in pain, any time an animal is in pain, and perhaps even any time a computer program realizes that the computer in which it resides has been damaged somehow. Functional dualism is not necessarily this all-inclusive, however. There may turn out to be some reasons to conclude that a physical being must have a certain package of mental functions in order for any qualia to exist, which might in turn imply that the operations of simple beings (perhaps including some or all animals), and simple computers do not cause qualia to exist and are thus not phenomenally conscious but are instead zombies.
In comparing the three partial solutions to the Cause of Qualia Problem that are listed here, it makes sense to first eliminate anomalous dualism because it is not naturalizable, while the two versions of parallelism are. Functional parallelism can apply more easily to diverse beings that seem to have similar features, so it makes sense to conclude that qualia are caused to exist by the functional features of beings, whatever they might be made of and however they go about implementing the necessary functional features. Despite this realization, there might still be reasons to conclude that some types of beings have qualia while some do not. Functional parallelism can either work in a way such that each physical thing that has a certain functional quality has a nonphysical counterpart, or else possibly this parallelism could actually be restricted to only include physical things that have a certain complex package of functional features. A further analysis will be necessary to figure out whether all animals and humans have phenomenal consciousness or whether humans alone do or whether even nonliving things such as computers, or perhaps even thermostats, do as well.
Before moving on, it is necessary to address a common criticism that it is supposedly impossible or inconceivable that anything physical could have a causal effect on anything nonphysical or vice versa. It is true that the conclusion provided here, that body states and events cause qualia to exist, ends up implying that there is a causal link between the physical and the nonphysical. This causal relation, however, is understood to be completely natural. Natural laws actually govern the behavior of both physical things and nonphysical things because they operate on all categories of being. It is certainly conceivable that a law of nature could be triggered by some physical state of affairs that has an effect on some nonphysical state of affairs or vice versa. If this happens, is not magical. It is just the way things are.