Those who are optimistic about the prospects of solving the problem of consciousness – how it is that first-person, subjective, conscious experience arises from purely electrochemical processes in the brain – often point to the extraordinary successes of the scientific method in other domains. Over the past century, we have made amazing strides in understanding the birth and evolution of the universe, made fascinating connections between the nature of space, time, motion, and gravity, decoded the human genome, and uncovered the bizarre behavior of particles according to quantum mechanics. The problem of consciousness is admittedly difficult, but, given the incredible discoveries that science has made in these other fields, there is no reason to believe that progress cannot be made towards solving this problem as well.
Thomas Nagel, however, urges us to temper our optimism. In his famous 1974 paper, “What Is It Like to Be a Bat?”, Nagel argues that the framework within which science is currently conducted – the very methods that have made science so successful in those other domains – is precisely what is preventing it from cracking the problem of consciousness. Now let me be clear: in no way is Nagel a “science skeptic”. What he is advocating is not an abandonment of the scientific method, but rather a paradigm-shift – a kind of revolution in its methodology that would allow it to accomodate the phenomenon of consciousness. Neither is Nagel a dualist or a spiritualist. He assumes, as do most scientists and intellectuals, that consciousness is wholly generated by purely physical brain activity. What he seeks to draw attention to is the way that the scientific method, as currently conducted, limits the scope of its inquiry, thereby preventing it from uncovering the precise way in which consciousness is generated by physical processes.
For Nagel, to be conscious is to be in the possession of a particular point of view; it is to have an experience of what it is like to be a particular organism (Nagel 160). Thus, consciousness is essentially subjective and qualitative, and any acceptable account of consciousness must explain the nature of this subjectivity. Nagel illustrates this point by inquiring into our knowledge of bats. Biologists have an extensive knowledge of the physiology of bats, and we can even conjecture that one day our knowledge of bat biology will be complete. Yet even then we would still have no understanding of how bats themselves experience the world (161). Bats’ sensory capacity for echolocation has no genuine analog with any of our human senses, and the limitations imposed by our conceptual resources make it impossible to extrapolate from our experience to the experience of bats. This thought experiment shows that facts about subjective consciousness are facts about a particular point of view, and it is impossible to truly understand the subjective consciousness of an organism unless one is capable of adopting that organism’s point of view, a feat that is impossible for us to achieve with respect to bats (162-163).
However, Nagel points out that physical descriptions, or at least our current notion of what counts as a physical description, necessarily leave out the subjective point of view constitutive of consciousness (160, 163). To see why this is so, consider the cases in which we strive to give an objective account of the physical world. Perhaps we claim that what appears to be the movement of the sun across the sky is in fact due to the rotation of the earth. Here we are explaining the subjective appearance in terms of our peculiar point of view, relative to the earth and the sun, and we reach the objective reality by abstracting from this point of view. In all cases where we attempt to move towards a more objective picture of the world, we abstract from all particular points of view, until we reach a universal perspective that is in principle equally accessible to all observers, regardless of their particular perceptual or cognitive apparatus. But since, in the case of consciousness, the subjective experience simply is the reality to be explained, it is incoherent to try to adopt the same strategy of removing the subjective experience in order to better understand the reality of consciousness (160, 163, 166). And since our notion of physical description requires an objectivity that abstracts from the particularities of subjective experience, it is difficult to comprehend what form a physical account of consciousness could even take (163).
This shows that a scientific discovery that, say, the presence of human consciousness is perfectly correlated with certain kinds of electrochemical processes, would still not satisfy Nagel’s demands for a sufficient account of consciousness. Such a physical description would be purely objective; it could in principle be understood by a host of different inquirers. Imagine that extraterrestrial scientists were to study human brains and make the same physical discovery. This knowledge would not provide them with any understanding of what it is like to be a human being. Their position relative to us would be the same as our position relative to the bat (162). And this is precisely because the standards of objectivity that would allow them to acquire this knowledge are those that remove the subjective point of view that constitutes the conscious experience in the first place.
The conclusion of Nagel’s argument is that the seemingly unbridgeable gap between the notions of subjectivity and objectivity make it impossible to see how the mental and the physical could both be accounted for under a unified description. What we lack is the conceptual framework that could show us how something that is essentially subjective could at the same time be known objectively (166). Until such a conceptual framework is found, we are not merely ignorant about how mental states can be identified with physical states (though we may assume they are). Rather, we do not know what it could even mean for a mental state to be a physical state (164). No number of neuroscientific discoveries can bridge this deep theoretical chasm.
In upcoming posts, I will continue to explore the theme of the scientific method’s inherent limitations, expanding the discussion beyond just the problem of consciousness. I will take a look at Edward Feser’s argument that science cannot, even in principle, provide an exhaustive description of physical reality. This is because the scientific method abstracts from concrete reality, focusing only on those aspects of reality that can be subject to prediction and control, and can be measured quantitatively and expressed in mathematical equations and formulas. I will also explore the arguments of philosophers such as Bertrand Russell and Frank Jackson that natural science can only provide us at most with descriptions of the structures and “relational properties of physical objects”, but cannot give us any knowledge of their “intrinsic nature”. This is a position known as structural realism. Furthermore, I will delve into the arguments of feminist standpoint epistemologists that the purported objectivity and abstraction away from particular points of view that is so valued by current scientific methodology actually has problematic political and moral consequences. Specifically, it ignores the inherent situatedness of knowledge, glosses over the political character of knowledge claims, and elevates one kind of standpoint over others that knowers and knowledge-seekers might take.