Key Moments
Thomas Nagel: What Is It Like to Be a Bat? (Full Conversation)
Closer To TruthKey Moments
Consciousness may be a fundamental aspect of reality that current physics cannot explain, suggesting our universe is more than just matter and motion. This challenges the core of scientific materialism and implies a need for a radical rethinking of the physical world.
Key Insights
Nagel's 1974 paper, 'What Is It Like to Be a Bat?', remains highly relevant, with over 17,000 citations, because it highlighted the irreducible subjective aspect of experience that physicalist theories struggle to explain.
The scientific revolution, starting with Galileo and Descartes, achieved its success in understanding the physical world by deliberately excluding the mind, creating the problem of how to reintegrate it.
Many contemporary theories of consciousness, like those of Daniel Dennett, are fundamentally behavioral or functionalist, defining consciousness through its role in predicting and understanding behavior, which Nagel argues is insufficient.
Nagel suggests that a complete understanding of the universe must account for consciousness, value, and reason, not merely as byproducts of matter but as potentially fundamental aspects of reality.
The problem of consciousness is not just a local issue concerning human or animal minds but 'invades' our entire understanding of the universe and its history.
Nagel is skeptical of AI consciousness, arguing that current AI's reliance on linguistic output without a direct, independent connection to reality is insufficient to attribute consciousness.
The persistent problem of subjective experience
Thomas Nagel's philosophical career has been largely dedicated to exploring the challenge that consciousness poses to a purely physical understanding of the world. He argues that the subjective character of experience—what it's like to be a particular organism—is a fundamental aspect of reality that current scientific and philosophical frameworks struggle to accommodate. Nagel's seminal 1974 paper, 'What Is It Like to Be a Bat?', highlighted this issue by questioning how we could ever truly understand the subjective experience of a bat, even with complete knowledge of its physiology and behavior. This work, still highly influential today with over 17,000 citations, suggests that our current objective, third-person descriptions of the world, which exclude subjective qualities, are incomplete. Nagel contends that any comprehensive view of reality must find a way to integrate consciousness, not by reducing it to something else, but by acknowledging its unique and irreducible nature. This pursuit has led him to question the sufficiency of the prevailing materialist worldview, which emerged from the scientific revolution.
How the scientific revolution excluded the mind
Nagel points out that the very success of modern science, particularly physics, stems from its adoption of an objective, quantitative, and spatio-temporal view of reality. Thinkers like Galileo and Descartes intentionally set aside subjective qualities such as color, sound, taste, and consciousness itself, as these were not amenable to mathematical description. This methodological exclusion allowed for the development of powerful physical theories but created a significant challenge: how to reintegrate the mind and subjective experience into this increasingly detailed, yet seemingly 'mindless,' picture of the world. The mind-body problem, therefore, is not just an abstract philosophical puzzle but a consequence of the foundational choices made during the birth of modern science.
Critiquing functionalism and evolutionary materialism
Nagel expresses skepticism towards many contemporary attempts to explain consciousness, such as those by Daniel Dennett, which often rely on functionalist or behaviorist accounts. These approaches tend to define consciousness in terms of its observable functions or its role in information processing, which Nagel believes misses the core issue: the subjective 'what-it's-like-ness' of experience. He argues that simply explaining the sophisticated behavior or internal processing of an organism is not equivalent to explaining the subjective feeling itself. Similarly, he questions whether evolutionary explanations, which trace the development of complex organisms from simpler ones, can adequately account for the emergence of subjective awareness if materialism is fundamentally incapable of explaining consciousness in the first place. The evolutionary story, he suggests, would need to explain the origin of subjective experience, not just its functional correlates, which remains a significant gap.
The bat as a thought experiment
The famous 'bat' paper originated from a personal experience. While living in New York, Nagel had bats flying into his house in the countryside. He contemplated the problem of consciousness, realizing that even with effort, he could not truly imagine what it would be like to be a bat. This insight led him to conclude that our concepts of mental experience are deeply tied to our own subjective perspective, and this perspective cannot be easily projected onto other creatures. He moved away from an earlier idea that mental concepts rely on imaginative projection and instead focused on the need for an abstract conception that captures the subjective aspect without relying on personal imagination, thus formulating the core of the mind-body problem as explaining the link between 'what it is like to be' and the objective description of behavior and physiology.
Consciousness as a universal problem
Nagel argues that the problem of consciousness is not confined to biological organisms on Earth but is a problem that 'invades' our entire understanding of the universe. He posits that a purely materialist cosmology, such as neo-Darwinian materialism, is incomplete because it cannot adequately explain consciousness, intentionality, value, and reason. These phenomena, he suggests, might reflect fundamental features or tendencies of the universe itself, rather than being mere accidental byproducts of matter. This perspective challenges the notion that physics alone can provide a complete picture of reality and implies that our current scientific worldview might be fundamentally flawed.
The role of value and reason
Beyond consciousness, Nagel emphasizes the importance of value and reason as phenomena that are difficult to reconcile with a purely physicalist worldview. He views the objectivity of value and reasons for action as deeply controversial, with many opting for subjectivist or expressivist accounts. However, Nagel suggests that attempting to reduce value judgments to mere expressions of feeling is unconvincing, posing Socratic challenges to anyone holding such a view. He believes that if reason is connected to objective truth, then evolutionary accounts that merely explain functional thinking for survival are insufficient, raising doubts about the completeness of Darwinian explanations for our rational capacities. This leads him to explore alternative frameworks that can accommodate these non-material aspects of human experience.
Reconsidering teleology and the limits of materialism
In 'Mind and Cosmos,' Nagel revives the concept of teleology (purpose or design in nature), which has been largely excluded from scientific consideration since the Enlightenment. He argues that the emergence of complex beings with properties that seem to transcend purely physical explanations makes it reasonable to consider alternatives to purely mechanistic explanations. While he is an atheist and does not advocate for a religious creator, he believes that the possibility of inherent purpose or direction in the universe, perhaps a formal teleology, should not be dismissed. He suggests that the universe might have a tendency towards increasing complexity and the emergence of consciousness, a view that requires a departure from standard reductionist materialism. This is not about invoking divine intervention but about acknowledging that our current understanding of physics may be incomplete and that other explanatory frameworks might be necessary.
Critique of AI consciousness and the Turing Test
Nagel is highly skeptical of claims that artificial intelligence could become conscious. He points out that current AI, primarily driven by linguistic output, lacks a direct, independent connection to reality. Unlike humans who learn language in contexts grounded in their embodied experience and interactions with the world, AI systems process vast amounts of text without direct referential grounding. He also notes that while Turing's test assesses intelligence, it says nothing about consciousness. Nagel distinguishes between intelligence and consciousness, arguing that successfully mimicking human conversation does not equate to having subjective experience. He suggests that consciousness, as we understand it, is deeply tied to biological organisms, and while he doesn't rule out consciousness in different physical substrates, it would require a much more profound connection to the environment than current AI exhibits.
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Common Questions
Nagel argues that subjective experience, specifically 'what it is like' to be a conscious being, cannot be fully explained or reduced to objective physical science. He uses the example of a bat's echolocation to illustrate that even with complete knowledge of its physiology, we cannot know its subjective experience.
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Mentioned in this video
Professor Emeritus of Philosophy and Law at New York University, one of the most influential philosophers of our time, known for his work on consciousness, mind-body problem, objectivity, ethics, and limits of scientific explanation.
A philosopher whose current approach to mind-brain identity is likened to the 'Morning Star and Evening Star' analogy, suggesting that despite different conceptualizations, mental and brain states are the same underlying reality.
Cited by the host (as a voice of an AI) as an author whose entire body of work the AI has read and remembers, contributing to its superior writing style.
A philosopher and friend of the host, who posits value as the fundamental generative cause of the entire universe, more important than God or anything else.
Cited by the host (as a voice of an AI) as an author whose entire body of work the AI has read and remembers, contributing to its superior writing style.
Cited for her view on the subjective values of morality based on evolution, which Nagel agrees with in terms of the connection but reverses the order of causality.
A famous atheist and friend of the 'Closer to Truth' program, who shared a story explaining his aversion to the idea of God, primarily rooted in the desire for intellectual ownership of his creations.
Mentioned as a key figure in the 17th-century scientific revolution, whose work contributed to the exclusion of the mental from the description of the physical world.
Mentioned along with Galileo as shaping the concept of objective physical reality, which excluded the mind.
The man who discovered bat sonar (echolocation), and was encouraged by Nagel's work to take animal consciousness seriously.
Philosopher known for his evolutionary argument against naturalism, suggesting that if evolution is true, it becomes self-defeating for the mind used to understand it.
Philosopher who radically revised the concepts of necessity, contingency, analyticity, syntheticity, a priori, and a posteriori in 1970, and whose modal argument challenged the Mind-Brain Identity Theory by asserting that if the identity is true, it must be necessarily true.
Cited by the host (as a voice of an AI) as an author whose entire body of work the AI has read and remembers, contributing to its superior writing style.
A philosopher who proposes that conscious beings and mental states can be understood functionally, explained by natural selection.
Philosopher who, along with J.J.C. Smart, introduced the Mind-Brain Identity Theory as an alternative to behavioral analysis for sensory experiences.
Pioneer of theoretical computer science, whose 'Turing Test' is discussed in relation to distinguishing intelligence from consciousness in AI.
Mentioned as a philosopher whose book 'The Concept of Mind' analyzed mental language based on observable criteria, contributing to a behavioral consensus in philosophy of mind.
Philosopher who, along with U.T. Place, introduced the Mind-Brain Identity Theory, arguing that mental states are identical to brain states as a contingent scientific identity.
Cited by the host (as a voice of an AI) as an author whose entire body of work the AI has read and remembers, contributing to its superior writing style.
Nagel's book arguing against postmodern skepticism about objective truth, logic, reason, and values.
Gilbert Ryle's book that analyzed mental language primarily in terms of observable criteria, influencing philosophical behaviorism.
Nagel's legendary 1974 article that reshaped the concept of consciousness, challenging the reduction of subjective experience to objective science.
Alan Turing's paper that introduced the Turing Test, distinguishing between intelligence and consciousness in machines.
Nagel's book that maps the tensions between the first-person lived world and the third-person described world.
Nagel's book questioning the sufficiency of neo-Darwinian materialism to explain the mind.
The institution where Thomas Nagel is a Professor Emeritus of Philosophy and Law.
The institution where Donald Griffin was a researcher.
The institution where the host pursued his PhD and conducted research at the Brain Research Institute without encountering discussions about consciousness in the 1960s.
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