Last week, my 13.7 co-blogger Tania Lombrozo reported on a study she developed with graduate student Sara Gottlieb on whether science can explain the human mind.
As Tania wrote, this was a survey-based study asking the participants "whether they thought it was possible for science to one day fully explain various aspects of the human mind, from depth perception and memory loss to spirituality and romantic love."
On average, the study found, people judged that certain mental phenomena — such as depth perception or the sense of touch — to be "much more amenable to scientific explanation than others — such as feeling pride or experiencing love at first sight."
According to the participants, the dividing line separating what science can and cannot explain seems to be the perception that some mental phenomena, for example, religious devotion and complex decision-making, "involved an internal experience accessible through introspection" that distinguishes us from other animals that share with us sensorial experiences, such as seeing and hearing.
As Tania remarked, these findings "don't tell us what science can or can't explain. They tell us about the beliefs about what science can and can't explain." The question, then, is: "What do people think explains the human mind, if not science?"
This is an interesting point that merits further discussion. Is the mind explainable?
To Tania's quote by Ambrose Bierce, I add another by Victorian physicist John Tyndall. It is, to me, remarkable that as early as 1868 the issues that we are grappling with today were already so present. Here is Tyndall, in his address to the Physical Section of the British Association for the Advancement of Science:
"The passage from the physics of the brain to the corresponding facts of consciousness is unthinkable. Granted that a definite thought, and a definite molecular action in the brain occur simultaneously, we do not possess the intellectual organ nor, apparently, any rudiment of the organ, which would enable us to pass by a process of reasoning from the one phenomenon to the other. They appear together and we don't know why. Were our minds and senses so expanded, strengthened and illuminated as to enable us to see and feel the very molecules of the brain, were we capable of following all their motions, all their groupings, all their electric discharges, if such there be, and were we intimately acquainted with the corresponding states of thought and feeling, we should be as far as ever from the solution of the problem. How are these physical processes connected with the facts of consciousness? The chasm between the two classes of phenomena would still remain intellectually impassable."
In other words, we may identify the physiological activity related to a feeling, locating in specific or combined areas of the brain. We may identify not just the neuronal firing but also the chemicals flowing from point A to point B as the feeling is felt. But such scientific descriptions of the phenomenon will still not illuminate the feeling itself. There is something missing here, a gap in our explanatory argument that fails to link physicochemical phenomena with the ineffable experience of feeling something. And it doesn't need to be anything as lofty as love or religious ecstasy. Kicking a stone will do it, as one can locate the regions in the brain associated with the pain but can't grab on to how the firing of specific neurons translates into having pain or why certain kinds of pain make you cry and others don't, be the pain physical or emotional.
This is what philosophers such as David Chalmers, Colin McGuinn, and others call the Hard Problem of Consciousness.
An obstacle to applying the usual scientific methodology here is that a feeling is a hard thing to objectify — that is, to isolate from "everything else." When one kicks a stone, it's not just the brain that is involved: Pain is a full-body experience, localized at the point of contact, capable of making us tear-up, but orchestrated all the way up in the brain. It connects brain and body in inseparable ways. Love is similar. You can experience it in the body, as hormones race along to speed up your heartbeat and the release of pheromones. There is a physiological aspect to pain and to love, but there is also something unique about the experience, something personal and subjective, something that is not easily objectified. And what science can't objectify, it has trouble describing.
Tania's, and Sara Gottlieb's, survey response voiced a general intuition that Tyndall's text so beautifully captured. A strict reductionist approach that takes a bottom-up methodology to the mind seems to be missing something essential about what's really going on. It is not that science is unable to ever figure out the mind, or that the problem of understanding the mind is that we can't step out of it. The problem is that this kind of approach, focused on local cause and effect mechanics within the brain, on neurons firing across their synaptic connections, is doomed to fail.
The mind is a challenge because it works more like a city than a household, with several networked links resonating at different times and with different subgroups of nodes, such that understanding the behavior of individuals or even of smaller groups won't tell the whole story of what's going on. No approach can capture the whole of what goes on over time in a large city like New York or Rio, even if a city is made of small neighborhoods — and those neighborhoods, of a few individuals. One may capture certain mass events, like rush hour traffic or festivals, parades or open-air concerts, but not the global behavior of the city. You can describe a city, its neighborhoods and museums, its history, but not explain it, at least not in some clear deterministic way. As Nobel Prize physicist Phil Anderson once remarked: "More is different."
In the case of the human mind, it's different in ways that are extremely hard to qualify, at least for now. We may make some progress if we are ever able to create machines that are somehow capable of some kind of rudimentary self-awareness and not just of following complex program instructions. Catching the emergence of such minds in the act, so to speak, may teach us how to begin to make sense of our own, at least partially.
But we remain far from such machinery, and are still as ignorant about the "passage from the physics of the brain to the corresponding facts of consciousness" as Tyndall and his Victorian colleagues were.
Marcelo Gleiser is a theoretical physicist and writer — and a professor of natural philosophy, physics and astronomy at Dartmouth College. He is the director of the Institute for Cross-Disciplinary Engagement at Dartmouth, co-founder of 13.7 and an active promoter of science to the general public. His latest book is The Simple Beauty of the Unexpected: A Natural Philosopher's Quest for Trout and the Meaning of Everything. You can keep up with Marcelo on Facebook and Twitter: @mgleiser