Facts, Properties and the Mind-Body Problem
In considering the mind-body problem, many philosophers conclude that the ‘explanatory gap
’ means that there are nonphysical facts about consciousness
; basically, that consciousness cannot be characterized in purely physical
facts about brain
s. This is because it does not appear that any sort of physical explanation
can ‘get at’ what it feels like to see red. But it seems possible, even likely, that brain-states identify
-states, and therefore that there are facts about the brain that identify to facts about conscious states, or that (in other words) when certain proposition
s become true about the brain, that corresponding propositions become true for the contemporaneous state of the mind. And this seems to agree with our everyday experiences
s, for instance, are all of the elements from which our visual experience is composed; whenever we open our eyes in the presence of visible light
, we experience color. Individual colors are not unique
, but rather recur in our experiences, and their recurrence is directly related to the physical properties of the things that reflect (or, sometimes, project, such as in the case of the sun, or light bulbs) visible light into our eye
s. We see everything that reflects electromagnetic radiation
with the wavelength
of 600 nanometers
to be a certain orange-y color, and whether one person’s feeling of ‘orange-y’ is the same as another’s, there is a law-like consistency of the relationships between the energy levels of the light that strikes the retinas and the sensation that occurs for the mind as a result. Clearly, if this were not the case, the human eye would be an ineffective (and probably counter-productive) sensory apparatus.
So why are facts about brain-states insufficient to explain consciousness? This is an important question that gets far too little attention, considering the tremendous interest in the mind-body problem among recent and contemporary philosophers. It appears that the answer is, none of the physical facts of which we know explain the ‘is’/‘are’ of brain-mind identity. This means that, when we identify brain-states to mind-states -- and therefore basically say that ‘brain-state x is mind-state x’-- there is still the question of what ‘is’ means. When I say that “This ant is alive”, it is because this ant exemplifies cell theory, and would therefore be considered ‘alive’ by most authorities -- so ‘is’ has a substantive implicit meaning. But in the case of mind-body identification, such a meaning for ‘is’ is absent.
Some philosophers have posited psycho-physical laws, principles that describe the relationship between the brain and the mind in lieu of scientific data. Generally, ‘psycho-physical laws’ do not require a dualist or physicalist view; that is, the dualist and the physicalist can both maintain that there are principles that correlate brain-states to mind-states. However, the dualist holds that these principles correlate physical facts to nonphysical facts (sometimes facts about nonphysical substances, sometimes facts about nonphysical properties), and that this is for exactly the reason I mentioned at the beginning of this essay – that it does not seem that physical facts as we know them are enough to explain consciousness. But what defines a ‘physical’ fact? Which properties make something ‘physical’?
This question puzzles me. Even property dualists, who believe that matter is the only substance in the universe, believe that there is a class of properties, mental properties, which is ontologically distinct from physical properties. But what actually distinguishes mental properties from physical properties? I do not know of any account that explicitly resolves this question. Frank Jackson’s ‘Knowledge argument’ may be the most famous argument in support of property dualism, and it fails to make the fundamental distinction. Jackson claims that a super-scientist locked away in a black-and-white room her whole life could learn all of the physical facts relating to vision, but that once she stepped out of the room she would have experiences that none of her physical knowledge could afford her. But could she have learned nonphysical facts (about mental properties) in that room that would have ‘given her the color experience’? Maybe I only ask this question because I cannot conceive of knowledge of any sort bestowing a subjective experience, and maybe my question is irrelevant. But if nonphysical facts can be learned, and can bestow subjective experiences like color sensations, then how can the relationship between the acquisition of nonphysical facts and the triggering of those mental properties of the brain be explained? For this I am inclined to say that there cannot be an adequate answer, as long as we are wanting for an understanding of ‘mental properties’. But what if it is impossible to learn nonphysical facts? This would seem to imply that we cannot understand anything about mental properties, rendering all reductive methods of getting at psycho-physical laws invalid and truly realizing an ontological difference between the physical and the mental. My problem with the theory of such utterly inaccessible nonphysical facts and mental properties is that they suggest that brain-states would not identify to mind-states, and I am not aware of any evidence for this suggestion.
It seems irrational to distinguish physical facts from nonphysical facts, physical properties from nonphysical properties, on an epistemological basis. Whether Jackson’s super-scientist has new experiences when she steps from her black-and-white room or not is irrelevant to the issue of whether the properties of the material things that are responsible for generating subjective experiences are ontologically physical. Maybe I can clarify with a hypothetical experiment. Jacob is a neuroscientist, and he is conducting a study in an attempt to isolate facts about human brain-states that are relevant to the generation of the color experience. He puts each of his subjects in a room painted entirely in purple, with the lights out. He begins scanning their brains with cutting-edge magnetic imaging technology that senses the position of every molecule in its scope. He flips the lights in every room on, observing and recording his subjects’ brain-states every nanosecond for three minutes. Does it not seem reasonable that Jacob should find facts about every brain that remain true for the duration of the study, and that became true with his flipping the lights? Maybe these would not be the only relevant facts, but they would probably be a good start in an effort to determine which physical processes give rise to color sensation; and if this is so, then it would seem that these physical facts would fully or almost fully account for the subjective sensations that each of his subjects has. These facts may not be about individual molecules or cells, but maybe systems, or the brain as a whole; and if this were so, then it would seem that properties could be deduced for individual cells or molecules that relate to their role in the holistic system. Would these properties not be physical, having been deduced from physical facts?
Obviously my experiment ignores the explanatory gap altogether; there is nothing about trying to intuit color by ‘thinking about’ physical facts present whatever, as there is in Jackson's 'Knowledge argument'. But its purpose is to say that the explanatory gap is not so important if a perfect account of sensation is possible. Furthermore, another purpose is to show that arguments like Jackson’s fail to justify belief in ‘nonphysical facts’ and ‘mental properties’ based on the sentiment that uncertainty about the consistency of human experience is not grounds for presuming that there are facts about the mind that are not also facts about the brain. Why does it matter that I cannot be sure that red feels the same to me as it does to you? Really, I assume that as long as your brain is basically the same as mine that it must, and that is reasonable based on what is known about the human body. The incommunicability of the subjective hardly refutes that.