It seems fitting, at the start of this effort to understand consciousness, to begin by reviewing the frequently referenced essay by philosopher Thomas Nagel, “What is it like to be a bat?”
Published in The Philosophical Review in 1974, Nagel’s words have been echoed and debated by philosophers and scientists ever since. In essence, Nagel argued that consciousness is a subjective experience — different for each species and each individual — and that there were no existing philosophical approaches that could explain the physical basis of consciousness objectively. Given that, any attempt at reductionism moves the thinker farther from understanding the phenomena of conscious experience.
Though the technologies to study brain and mind have advanced far beyond what was available in 1974, the limitations imposed by our subjective human experience is still very much an active argument. Exactly this question was discussed in a recent two-day workshop attended by scientists and philosophers, called “The Blind Spot: Experience, Science, and the Search for ‘Truth’.”
“The debate comes down to the question: Is the world knowable through dispassionate scientific study, or hopelessly viewpoint-dependent and full of blind spots?” Dan Falk, Scientific American
The major themes of the workshop are described in this Scientific American article:
Cosmos, Quantum, and Consciousness: Is Science Doomed to Leave Some Questions Unanswered?
Physicists, philosophers debate whether research can ever solve certain mysteries of the universe — and the human mind
Consciousness is viewpoint-dependent, so how can we ever understand it? Though Nagel did not believe we could understand the physical basis of consciousness in 1974, he did not rule out the possibility that it may someday be knowable. Let’s dive deeper into Nagel’s famous article.
A fundamentally alien form of life
To illustrate the subjective nature of consciousness, Nagel had us try to imagine what it is like to be a bat.
“Bat sonar, though clearly a form of perception, is not similar in its operation to any sense that we possess, and there is no reason to suppose that it is subjectively like anything we can experience or imagine.” Nagel
He convincingly argues that it is impossible for us to understand what it is like, instrinsically, to be a bat. Our bodies and brains are structured in a different way, and we use different senses to perceive the world.
Jump to present day, and we have done experiments to understand how the bat brain uses echolocation to create a mental map of its surroundings and navigate through their environment. Yet we still have no comprehension of what that is like for a bat. What is a bat thinking and feeling as it moves through the world? How does it integrate that incoming sensory stream into a larger sense of self and memories of prior experience?
We can try to imagine this, but that is to overlay our subjective experience as a human being onto the bat. When we peer into the minds of freely behaving bats with microscopes and electrodes we cannot help but to use those tools as a looking glass. Everywhere we look we see reflections of ourselves, rather than the thing itself.
“I want to know what it is like for a bat to be a bat. Yet if I try to imagine this, I am restricted to the resources of my own mind, and those resources are inadequate to the task.” Nagel
You don’t know me
Nagel pointed out that even within our own species we cannot necessarily understand the experience of another person. He gives the example of trying to understand the experience of someone blind and deaf from birth.
All we know is our own experience. Even when exposed to an identical objective process, every individual has a subjective experience of that process.
“Members of radically different species may both understand the same physical events in objective terms, and this does not require that they understand the phenomenal forms in which those events appear to the senses of members of the other species.” Nagel
This issue exists between every individual of the same species, not just those with major sensory differences. We may even be more prone to error when trying to understand other people because we often assume that their internal world is similar to our own.
As evidence that another person’s internal world is in fact not the same as ours, consider how hard it is to communicate your experience to someone else. No matter how receptive, empathetic, or imaginative the other person is, they will, necessarily, be considering your experience relative to comparable experiences of their own.
The best communicators use an iterative process, repeating or restating what they think the other person was trying to say and asking if that is correct. If you try this out for yourself you will quickly discover that you are often misinterpreted. Even if you are interpreted accurately, putting experience into words is already several steps removed from the experience itself, and will become more removed when colored by the other person’s subjective experience.
The solution is in the problem
“If the subjective character of experience is fully comprehensible only from one point of view, then any shift to greater objectivity — that is, less attachment to a specific viewpoint — does not take us nearer to the real nature of the phenomenon: it takes us farther away from it.”
If consciousness is by its nature a subjective experience dependent on one point of view, then it must be studied in individuals.
Experiments aimed at understanding mental processes are typically done in multiple individuals, then the measurements taken across those individuals are lumped together. Individuals are grouped based on differences relevant to the question being considered, and statistics is used to compare trends between groups.
This had to be done and still needs to be done, but to understand consciousness there is also a need to study individual differences and variability.
There are a growing number of researchers considering individual differences. This is most common in human cognition studies using MRI, but individual studies are also starting to happen more often using other approaches and in model systems. There have been a few pioneers in the study of individual differences who have been at this for years, but for the most part this is new territory.
Three big changes have made the study of individual differences a more scientifically rigorous possibility.
One, thanks to a great number of technological advancements, cognitive and systems neuroscience has shifted toward experimentation in awake and alive, behaving animals. Now we can study neural processes as animals are engaging in cognitive tests, making goal-based decisions, or learning to use new tools. The wealth of information that has come from these studies is indeed rich, but I have felt conflicted about this shift since I started my PhD studies in 2005 and witnessed these techniques in action. My hope is that this is but a brief, barbaric time — a necessary step toward the development of superior, less invasive tools that accomplish the same goals. New tech is trending in a more humane direction.
Two, there are a number of magnetic, optical, or electrical read-write systems that have been developed or are in development. Read-write devices can both record and stimulate neuronal activity, and can be used to test hypotheses about how neuronal activity drives mental processes (i.e. creates an inner world) within individuals. Decoding of the recorded neuronal activity can be used to generate predictive models of how a set of neurons will respond to an incoming stimulus, or trigger a specific action.
Three, there are now standards to reference and compare to individual data, all being continuously improved upon. In some cases these references are made possible by lumping experimental data from different research labs where it makes sense to do so. In others, they are the focus of large research groups, such as the Allen Institute for Brain Science (see their collection of brain atlases here).
The necessary first step toward understanding individual experience is to study the physiological basis of mental processes within individuals, and to develop a theoretical framework that objectively explains those processes.
“Setting aside temporarily the relation between the mind and the brain, we can pursue a more objective understanding of the mental in its own right. … This should be regarded as a challenge to form new concepts and devise a new method — an objective phenomenology not dependent on empathy or the imagination.” Nagel
It has been 45 years since Nagel wrote “What is it like to be a bat?” and the effort to understand the mind is finally taking off in the neurosciences. Now is an exciting time to start paying attention.
The new kid on the block
When Nagel wrote that we should devise a new method, “an objective phenomenology not dependent on empathy or the imagination,” he was not talking about neuroscience research. Phenomenology is the philosophical study of consciousness. Though phenomenology aims to study the mind and experience, its focus is on systematic reflection rather than experimentation or data collection.
Neuroscientific studies of consciousness are immature, still finding their footing. There is still the sense that saying you are studying consciousness could be a career-killer. It still rings whackadoo outside of philosophy. Neuroscientists who study consciousness call it other, more acceptable names. Or put more generously, they use more precise names.
This is starting to change. Nature and Frontiers in Psychology now have collections of research articles listed as consciousness studies. The article itself may describe ‘neural correlates of goal-directed behaviors,’ or ‘emotional processing of sensory stimuli,’ or ‘attentional state effects on perception and decision making,’ but there it is, filed away under consciousness studies. Scientists are getting more vocal about their interest in understanding consciousness (see Koch, Tononi, Graziano). The Templeton World Charity Foundation just funded a “structured adversarial collaboration” in which researchers with competing theories of consciousness will researchers will collaborate to determine and publish their ideas of what experiments may prove or disprove their theories.
Neuroscience Readies for a Showdown Over Consciousness Ideas | Quanta Magazine
Some problems in science are so hard, we don’t really know what meaningful questions to ask about them — or whether…
I don’t have any data based knowledge of whether philosophers and scientists follow each other’s work, but I think if you asked the average scholar you would hear a resounding no. In my experience, this doesn’t happen except at the rare conference designed to bring these divergent approaches together to focus on a specific topic, or when an essay or study becomes wildly popular, as was the case with “What is it like to be a bat?”.
I think the study of consciousness is one area that would greatly benefit from cross-pollination, especially right now. Philosophers would benefit from an updated understanding of the physical processes that underlie mental processes, and neuroscientists would benefit from a review of insights gleaned over the last century of systematic reflection on consciousness.
Great, but will we ever know what it is like to be a bat?
I definitely believe that there are generalizable features of brain physiology that generate consciousness, and that science and philosophy will make sense of them someday.
My interpretation of Nagel’s essay is that understanding the physical processes that generate consciousness is just the first step. Ultimately he wants to understand subjective experience, and believes that there is no objective way to study subjective experience. How can I explain the experience of being me in a way that anyone else could understand?
Let’s get weird.
I mentioned above that there are new read-write devices in development. Some of those are specifically for use in human beings.
I talked about how read-write devices could be used within an individual to decode the function of certain neuronal patterns. Those patterns could then be “written” back into the same person’s brain to test for accuracy.
What if those same patterns were written into another individual’s brain? Would it trigger the same effect in that person? Let’s say we decoded the neuronal pattern associated with choosing between two options. Would we be able to take that information and trigger a different individual to choose option B 100% of the time?
If enough of one individual’s brain activity was decoded, could it be written into the consciousness of another individual? Could we then, through direct experience, understand the subjective experience of someone else?
Could this be accomplished across species? Perhaps the effect could be amplified using virtual reality. A bat could be decked out with microphones and vibration detectors and cameras in addition to their neural read-write device. If those same inputs were made into a human individual’s nervous system through virtual reality goggles and headphones and skin stimulators and their own read-write device, would that person be able to experience what it is like to be a bat?
10 years ago I would have said say nah, we are still too different. Now I am aware of just how adaptable the human brain is. We can rapidly learn to interpret unexpected sensory inputs (see prism goggles) or control new movement outputs (see brain-machine interfaces). Perhaps if we simulated the sensory inputs and neural processes of a bat well enough we would get to experience a day in the life.
If this fictional possibility was made real, would we ever know how true our experience was to the original? I think not, but it would still be one hell of an experience.