Writing · Book review
Review: "What Is It Like to Be a Bat?" by Thomas Nagel
Also published on Substack ↗
Nagel’s position on the “hard problem of consciousness” is specific and perhaps not representative of any other. The focus is primarily epistemological and concerns materialism’s—or physical reductionism’s—inability to describe subjective experience. He states clearly in the preface that he is not mystifying consciousness: “My essay is sometimes misinterpreted as claiming that because the subjective character of consciousness is beyond the reach of the objective physical sciences, it is beyond the reach of scientific understanding altogether.”
Because reductionism has always proceeded through objectification—moving as far as possible from the human perspective to construct objective models—psychophysical reduction, according to Nagel, faces a particular difficulty, since every subjective phenomenon is tied to a unique perspective, the very one that had to be eliminated to construct an objective model. It follows that none of the current physical reductionist models explicitly takes subjective experience into account, and that they are therefore all theoretically compatible with its absence.
Nagel concedes that phenomenological facts are objective in the sense that they are communicable, categorizable, and relatively understandable to humans when they concern other humans. They remain subjective, however, insofar as this understanding is available only to a similar being capable of adopting that perspective, whether through imagination or empathy. But if the factual elements of experience are accessible only from a single perspective, we cannot expect their nature to be revealed in the organism’s physical operations, which are independent of perspective and accessible to us even in other species.
To illustrate this subjective element that eludes reductionism, Nagel invites us to imagine what it is like to be a bat—a living being close enough to humans that there is no doubt about the existence of its subjective experience, yet sufficiently different that this experience remains inaccessible to our imagination, which always extrapolates from our own experience. He argues that a thought experiment, or even physical alterations—if they were possible—would never give us the bat’s perspective. For what is at stake is knowing what it is like for a bat to be what it is, not what it would be like for a human to be a bat.
Nagel does not believe that physicalism is undeniably false, but rather that there is no reason to believe otherwise in the absence of a theoretical framework that would allow us to propose an identification of the form “mental events are physical events,” as is the case, for example, with special relativity for “matter is energy.”
Nagel’s speculative proposal, in his own words, is to seek a more objective understanding of the mind as such. The goal is to develop what he calls an “objective phenomenology”—methods and concepts that would make it possible to describe, at least partially, the subjective nature of experience without resorting to empathy or imagination. Beyond its intrinsic value, this phenomenology would allow us to examine the physical basis of experience more intelligibly. He believes we must transcend or expand our concepts to grasp the most fundamental relationships between body and mind. For him, the mind-body problem is, ultimately, tied to the problem of the subjective and the objective.
Nagel’s essay is clearly articulated and, for the most part, convincing. However, I was left with a few unanswered questions.
Does reductionism work well up to the mind-body problem?
First, I was a little surprised to see reductionism called into question as if it failed only when confronted with the mind-body problem. I had other limitations in mind—ones of which Nagel must surely have been aware—notably those highlighted by complex systems, which teach us that certain systems cannot be understood through an analytical approach that breaks them down to study their components separately, since certain properties result from interactions between these parts and only make sense at the collective level (e.g., superconductivity). But Nagel’s critique of reductionism is different. It does not target constructionism but rather the reducibility of the subjective—the idea that everything that exists can be explained by physics and reduced to matter. However, in my view, there are some ambiguities regarding the objective nature or meaning of scientific understanding beyond reductionism.
Is science objective in the sense that Nagel defines it?
Nagel focuses on the subjective/objective question and offers a specific interpretation: he suggests that science strips away appearances to reach a hidden reality behind them, concealed by our senses and immediate experience. It seems to me, however, more accurate to say that scientific research strips away particular features and anything irrelevant to the object under study to generalize and isolate it more effectively. Mental events are not relevant until we start looking at living beings, and even then we would need to generalize properties and assign them to categories, since the goal is not to understand a single individual. This, incidentally, seems to be the aim of his objective phenomenology, but in my view, psychology and the cognitive sciences already address it.
As he points out himself, it’s normal not to find individual subjective experience directly in models that have gone to great lengths to abstract from it by focusing on what lies outside us. But first, can’t we work our way back to it? The initial approach does not inevitably determine consequent developments. And second, do we ever truly set aside the human perspective? There is no guarantee that our scientific models, however detached from and contradictory to our immediate experience, would be comprehensible to other species.
What would a scientific understanding of consciousness look like?
It is also difficult to imagine a scientific model that, in Nagel’s sense, would give us a satisfactory understanding of subjective experience. I get the impression that the understanding demanded here, and by other defenders of the hard problem, for subjective phenomena goes beyond our understanding of objective phenomena. The bat example further suggests that we are simply observing the impossibility of having other consciousnesses alongside our own. So the aim wouldn’t be to understand consciousness or subjectivity through scientific models, but to exist as something else—to “live” or to feel that subjectivity. In this sense, can we really say we understand anything at all? Don’t we simply have models and frameworks that help us navigate the world better? Our capacity to conceive is limited; consciousness is not less accessible than other phenomena. In approaching the subject, Nagel says he will not address the relationship between facts on the one hand and conceptual frameworks or systems of representation on the other. That’s unfortunate, because this relationship lies at the heart of the subject and his epistemic problem.
Nagel says few studies have addressed the following fundamental question: Does it make sense to ask what my experiences really are, as opposed to how they appear to me? He argues that the hypothesis that they are physical in nature rests on the existence of an objective reality. A better question for me might be: How does mental experience manifest on a physical and dynamic level? What would be a good model for describing consciousness?
Do we truly understand other people’s subjective experiences?
Nagel says we can understand subjective experience only because we can feel it ourselves. But, as I’ve said, this kind of understanding doesn’t apply to anything else. Without going that far, I’d say we realize this when we have certain experiences for the first time, especially strong ones like a breakup or the death of someone close, or extremely unique ones inseparable from a stream of previous experiences; we often find that they can’t be expressed in terms of other experiences we’ve had. We often resign ourselves to saying you have to experience them to understand them. There always remains something that can’t be fully conveyed, and if we have very precise words to describe some of them, that is proof of their distinctiveness from other experiences rather than proof of their communicability. This raises further questions about language and its role here—as something that both shapes and is shaped by our experience and sociocultural contexts—and about how translatability depends on the precision of our vocabulary.
What are we looking for in physics?
For Nagel, science will succeed when it establishes the link between body and mind, between the physical and the mental. If we set consciousness aside for a moment—the overall feeling of being conscious, which I think must emerge from the interaction of more fundamental sensations and emotions—the goal would be to provide a physical description of these elementary sensations. As we saw with Damasio, neuroscience still cannot trace the complete physical pathway from stimulus to sensation, but that is not the issue. Even if we could fully map that pathway, build a complete physical model, and reproduce these sensations in other organisms, Nagel would still argue for a “nonphysical” dimension. In my view, the mistake here might be returning to a purely materialist paradigm and treating subjective experience or basic sensation as a single physical unit, even though that basic sensation might already be multiple and dynamic.
This piece is also on my Substack — read or subscribe there ↗.