What is the ultimate nature of reality? In Philosophy of mind, there are many positions regarding what has real being. On a commonsense level, dualism seems to be the reality. Thoughts, beliefs, and qualia really do seem to be different from tables, apples, and automobiles; therefore, according to dualists, there are two types of stuff furnishing reality. However, the gap that bridges the mind and body remains a mystery– no one has yet explained how they interact. To put it another way, how does a physical brain state, consisting of neurons firing, cause the associated mental event, that just is a feeling of pain, or any feeling at all?
Many philosophers have argued that the physical sciences show the way to the answer. On this view, the unparalleled successes of scientific predictions and explanation justify the belief that all reality is physical. One expression of this physicalist account may be found in cognitive neuroscience. To explain vision, neuroscientists will point out that the first physiological response to light is biochemical, occurring in the photoreceptor cells in our eyes. From there, as electrical patterns, the signal travels to the back of the brain, into the occipital lobe, and subsequently to other areas. The physicalist will assert that conscious experiences are actually nothing other than a property of neural events just described.
Many other philosophers question whether science can provide an account of everything that exists. We do not see electrical patterns– we see colors, cars, pedestals, and people. How is this even possible? “Qualia” is the term currently used by some philosophers to refer to conscious phenomena they believe lying outside the scope of scientific explanation. The redness of red, the small of a rose, and the feeling of pain, they claim, are nothing like atoms, wave-length, quarks and gluons, or any of the other phenomenon which form the subject matter of the physical sciences. In this paper I will argue that this view is correct, and that there are phenomena that can never be accounted for from the scientific perspective.
Frank Jackson’s “Mary Problem” gives a clear, concise contemporary argument for the existence of qualia, which he claims, are not physical. About a woman raised in a black-and-white environment, this is the Mary Problem:
Mary is a brilliant scientist who is, for whatever reason, forced to investigate the world from a black and white room, with a black and white television monitor. She specializes in the neurophysiology of vision and acquires, let us suppose, all the physical information there is to obtain about what goes on when we see ripe tomatoes, or the sky, and use terms like ‘red’, ‘blue’ and so on. She discovers, for example, just which wave-length combinations from the sky stimulate the retina, and exactly how this produced vie the central nervous system the contraction of the vocal chords and expulsion of air from the lungs that result in the uttering of the sentence ‘the sky is blue’. (Quoted in Heil p.765)
One day she leaves the lab and walks into the sunlit world, and she experiences color! In the view of those who believe in qualia, this means that she learns something new that the study of physics could not tell her. Therefore, Jackson claims, the Mary problem shows that physics, in the black and white room, does not account for all of reality. All that physics could have taught Mary is what we typically refer to as objective descriptions of the physical world, which can only describe color as radiation wave-lengths that hit the retina and send patterns of electrical signals to the brain. What is missing in the neuroscientific equation is the actual conscious experience of color seen.
The philosopher and neuroscientist, Daniel Dennett, believes that the problem of qualia should be dispelled. To make his case, Dennett argues that we ought to focus on a premise in Frank Jackson’s “Mary Problem” argument. If we recall, Jackson says that Mary knows, “all the physical information…” (765). However, Dennett asserts, if Mary knew all the physical information there is to know about color, then she would not learn anything about color, when stepping outside. He states boldly: “she knows everything– absolutely everything–… about the physical causes and effects of color vision” (399). Therefore, Dennett claims that, Mary would have predictive power regarding events in the physical world, since everything to be learned is ultimately describable in physical terms. According to Dennett’s critique, “[Mary would know] exactly what physical impression a yellow object… would make on [her] nervous system” (Dennett 399-400). He concludes, “So the only task that remains is for her to figure out a way of identifying the relevant neurophysiological effects “from the inside” (p.400). By figuring out that some color isn’t yellow or red, from knowing the physical reaction that yellow would have on the nervous system, Dennett believes, she would then be able to open the flood gates to the color spectrum—before exiting the black and white room. Dennett finally concludes that the existence of color as “qualia” is null and void, for there is no actual objective evidence of it, only our own reports of allegedly private perceptual experiences.
Let us review Dennett’s argument further. Jackson is stating that physics is not complete because there is a subjective aspect to our consciousness. For this part, Dennett wants to show that physics can describe everything that truly exists. The first way in which Dennett’s argument falls short is in its emphasis on knowing by description rather than on knowing by the actual experience. For supporters of the Mary Problem, even though Mary presumably knows all that physics conveys, she cannot know what it is to see the color red when she leaves her black and white room. As of yet, no one knows how physical brain-states interact with events characterized as “mental”. It may be the case that all physics can ever do is describe phenomena, external to our mental states. This leaves a problem for physicalists, like Dennett, for how does one describe the sensation of color to one who hasn’t seen the redness of red? As a supporter of the Mary Problem myself, I claim that It’s finally left to our conscious experience to actually sense the phenomenon, called qualia, like the feeling of a pain or perception of color.
Secondly, without the actual prior experience of color, Mary has no way to associate the relevant neurophysiological events with the qualia experienced. Dennett’s solution for Mary is merely to have her study neurophysiological effects on her own brain. Neurophysiological effects are one thing, but now Dennett wants to suppose color is a neurophysiological effect that is reducible to physical terms, but what is relevant is that the qualia actually experienced are qualitatively different, not quantifiable or reducible to the physical sciences. And since these are different in kind, rather than in degrees, Dennett will hit a road block when attempting to reduce something not reducible in physical terms. To illustrate the issue, using an example from Leibniz: “imagine a brain that is blown up to the size of a building. Upon entering, all we see are [physical] parts working on each other; nowhere do we find anything that explains or shows perceptions [known as qualia]” (Leibniz P.50). So, Dennett’s argument basically restates the issue: how is Mary going to associate the relevant brain response with the color if she hasn’t seen the color prior to the neurophysiological response? Viewing the brain’s physical makeup in motion will not explain color as seen by Mary when looking out into the colored world. Therefore, Dennett’s solution for Mary– which is studying neurophysiological events functionally– still presents Mary with a gap.
At every corner we turn we again bump into this explanatory gap, between mind and matter. Dennett’s solution, which is opposed to common sense, is ultimately to deny that we have the subjective sensations other philosophers call “qualia”. While Dennett is correct in claiming that humans can’t “objectively” prove the existence of qualia– I can’t help but feel Dennett is missing an essential ingredient of consciousness, if qualia are left out. To dilate on this, is it not self-refuting to deny one’s own sensations? To have perception, at a bare minimum, means that one knows what it is like to be conscious.
Dennett is not alone in his view of subjective experience. As a result of the “Enlightenment”, one of the beliefs some people do hold is that the physical world makes up all that is reality. However, we would do well to acknowledge that if we set out to describe all of reality, using a method designed to discover only what is physical, then our conclusions must be that everything is physical. On this model, of course physics is complete! I am not here denying the success of scientific achievement, I am merely pointing out this limitation. A scientific method, limited to objectivity, has no capacity for discerning what lay beyond the range of scientific description. Daniel Dennett shows us a picture of a machine, but a machine is, as Leibniz says, simply a set of physical parts working on each other. Would this machine smell coffee, or a burning sensation if spilled on the machines lap? No matter how many pieces we add to the machine, it seems as if it won’t welcome qualia, unless it could have that extra ingredient, conscious experience.