Mind the Explanatory Gap



Dualism is dead – it’s been dead for a while now, actually, and is beginning to smell a bit. Somebody ought to take it out. Ask any scientist, philosopher, or academic involved in the study of the mind and you will discover this in no uncertain terms for yourself. The notion that the mind and body are separate is an antiquated one heavily influenced by religious ideas about the separation of the soul and the corporeal, physical body. Given the current state of science, this perspective is, effectively, untenable.  Physicalism, instead, has long filled this explanatory vacuum and has shaped modern notions about the mind and its relationship to the body. Whereas previously, the two were believed to be separate entities, physicalism purports that the mind is a product of the body’s natural function. In much the same way the beat of your heart follows from its regular function, so too does your mind from the regular function of your brain. Namely, the mind, consciousness, and cognition follow from the activity of neurons in the brain. It is the coordinated activity of structures from the sub-cellular to the systems level from which your entire conscious experience springs forth. Every last element of the things that make you the person you are – your preferences, your dreams, and your tastes – all of these come from the firing of neurons in your brain. Essentially, then, a brain is a necessary and sufficient condition on having a mind. Without a brain, there is no mind – simple enough.

This is all well and good and relatively uncontentious and, as far as theories of the relationship between the body and the mind go, will provide Joe Everyman with sufficient intellectual mileage. For some, though, there is something missing in these Physicalist theories of mind, something they are not quite capturing about the experience of having a mind. It is one thing to say that the activity of a network of neurons yields a memory of your favorite song, but to explain how this activity actually produces the experience of the memory is something else entirely. The answer might seem obvious, laying out in the open, even – it is the firing of the neurons that yield the memory. Indeed, you can stick me in an fMRI machine and, as I think about my grandmother, tell me that particular regions of my brain may be playing a role in my memory of her. However, when my eyes are closed, there is a real feeling that I can see her and that this experience is housed somewhere. This disjoint, this break between the activity of the brain and the phenomenological experience of consciousness, was first noted by Joseph Levine in a 1983 paper entitled “Materialism and qualia: The explanatory gap”. Briefly, Levine was troubled by the fact that physicalist theories could make claims such as “Pain is the firing of c fibers”, a fact that is unequivocally true, without explaining how the firing of this neuron actually translates into the qualitative experience of pain. If I look at a rose, photoreceptors in my retina fire and are ultimately processed in the visual cortex, but this does nothing to describe how I actually have the experience of redness.

Before proceeding further, I would like to state that I am not espousing any dualist leanings here – the mind must necessarily be a product of the brain’s activity. My intention, rather, is to bring to bear the point that science has a tremendously difficult gap to bridge in providing a full account of what it is to have a mind. This issue is not an easy one to address, but I do not think it is outside of the scope of our ability. In thinking about this issue, I find the following analogy demonstrative. Imagine the brain as a digital projector. It receives input (say, for example, Rodney Dangerfield’s Back to School), and this input causes it to illuminate certain pixels in certain colors. Physicalist accounts, as they stand, stop here. Indeed, the pixels are changing and, by all accounts, the movie is chugging right along, but this in no way accounts for the experience of watching Back to School. This is the question Physicalism must strive to answer. This is the question scientists of the mind and brain should be aiming for – who, my friends, is watching Back to School?