The Ghost of the Other: A Physicalist Take on the Projection of Consciousness

> Translator's note on the introduction: The Other in philosophy refers to another subject with independent consciousness, usually contrasted with the self. But under physicalism and logical positivism, is this concept merely an illusion of our language and thought? This post deconstructs the Other as a metaphysical hypothesis and examines its place in physical logic.

Imagine standing in a busy train station. Every passerby seems to have their own story, their own consciousness—like independent planets spinning in the universe. But when we put on physicalist glasses and measure the world with the ruler of logical positivism, are these Others really irreducible centers of consciousness, or just phantoms projected by our brains, like the alchemists who believed a soul resided somewhere in the body?

From Physical Systems to Causal Interaction

The core claim of physicalism is simple and unsentimental: everything in the universe reduces to physical entities and their interactions. Like a giant cosmic billiards game, all the balls—particles, fields, energy—collide and roll according to physical laws, producing everything we observe, from quarks to galaxies, from neurons to social behavior.

In this worldview, the Other as a conscious entity independent of physical systems seems out of place. When you talk with a friend, the physicalist says: your friend is a complex system of carbon, hydrogen, oxygen, and other elements driven by electrochemical reactions. Your conversation is just causal interaction between two physical systems (two brains) via sound waves and light signals—like two supercomputers exchanging data over a network, where all meaning reduces to signal transmission and processing.

> Causal interaction is the core concept physicalism uses to describe relations between systems. Consciousness and emotion are treated as epiphenomena or emergent properties of physical processes.

From this view, your friend is not an irreducible subject but a complex network of neurons, synapses, and chemical signals. Their consciousness—if we grant it exists—is a functional output of that network, like an image on a screen being the result of circuit operations. Elevating the Other into a metaphysical entity is like searching for a soul in binary code.

The Illusion of Consciousness: Symmetry of Self and Other

If the Other has no footing in physical logic, what about the self? Imagine a fisherman casting a net and catching only reflections on the water. This is Daniel Dennett's Cartesian theater: we mistakenly assume a unified self sits in the brain's control room watching projections of the world. Likewise, we imagine the Other as another control room with an independent conscious resident. But the physicalist says: there is no control room. The brain has no center; consciousness is a collection of distributed neural processes, not an entity.

> Dennett's Cartesian theater metaphor criticizes Cartesian dualism. Physicalism holds that consciousness is a holistic effect of brain activity with no core self or other.

A metaphor: your brain is a busy city with countless streets (neural pathways), vehicles (signals), and workers (neurons) producing your thoughts and decisions. But there is no mayor—no single entity in control. We call the other brain an Other because language habitually labels these cities as if they had a unified soul. Under physicalism, this label is a linguistic illusion, like naming the wind and treating it as an entity.

The Tribunal of Logical Positivism: Verifiability and the Edge of Metaphysics

Logical positivism's core principle: a proposition's meaning lies in its verifiability. Concepts that cannot be verified by observation or experiment are meaningless noise. Can the Other as a center of consciousness pass this test? You can observe behavior, measure EEG, scan with fMRI—but these are all manifestations of a physical system. However deep we probe, we can never directly see the other's consciousness; we can only infer it, much like medieval scholars discussing angels or souls—possibly pleasant, but unverifiable in the third person.

Another metaphor: the other's consciousness is an invisible unicorn. You can observe hoofprints (behavior) and hear neighing (speech), but you can never catch it. The logical positivist says: since you cannot prove the unicorn exists, debating whether it is irreducible is pointless. Focus instead on observable phenomena: brain activity, behavioral patterns, causal chains.

Reductionism's Blade: The Difficulty of Mathematizing Consciousness

Physics describes interactions between systems precisely, e.g., Newton's second law \(F = ma\). Neuroscience uses mathematical models like the Hodgkin-Huxley model for neuronal electrical activity:

where \(C_m\) is membrane capacitance, \(V\) membrane potential, \(I\) external current, \(g_{Na}\), \(g_K\), \(g_L\) the sodium, potassium, and leak conductances, \(E_{Na}\), \(E_K\), \(E_L\) the equilibrium potentials, and \(m\), \(h\), \(n\) gating variables. This model precisely describes neural activity but cannot directly explain the subjective experience of consciousness.

The mathematization of consciousness remains an open problem. Theories like Integrated Information Theory (IIT) try to quantify consciousness via information-theoretic concepts, but they remain hypothetical and cannot directly verify whether the Other's consciousness exists. The physicalist might say: since we cannot describe the other's subjectivity mathematically, it may be a byproduct of our language and culture, like the soul abandoned by modern science.

From Self to Other: The Projection Game of Language

Why do we cling to the concept of the Other? Perhaps because human language naturally divides the world into subjects and objects. When we say I or you, we unconsciously assume these words point to unified entities. Wittgenstein noted that language is not a perfect mirror of reality but a tool full of conventions and limits. In *Philosophical Investigations*, meaning arises from use (language games): we use the word Other because it is useful in social, cultural, and ethical contexts, not because it corresponds to an independent metaphysical entity.

A down-to-earth metaphor: at a party, everyone describes the same cake in different ways—a sweet artwork, a collection of calories, a miracle of molecular structure. All useful, but none implies the cake has a soul or essence. Likewise, the Other is a linguistic label that helps organize social behavior without requiring an irreducible conscious entity.

Conclusion: Dissolving Phantoms and the Invitation of Science

Under the double scrutiny of physicalism and logical positivism, the Other as a center of consciousness dissolves into a phantom woven from physical processes and linguistic habits. Like the night sky, we think we see fixed patterns, but every star follows its own trajectory. Language makes us imagine these trajectories as Others; the scientific gaze reminds us that the universe contains only physical systems and their causal dance.

This does not mean the concept is worthless. In ethics, psychology, and sociology, the Other remains an indispensable descriptive tool. But from the perspective of physical logic, it is a projection error—an illusion shaped by language and culture, like the soul or geocentrism we once believed in. The invitation of science: set down these metaphysical burdens and rewrite our understanding of the world in observable, quantifiable language.

References

1. Dennett, D. C. (1991). *Consciousness Explained*. Little, Brown and Company. 2. Carnap, R. (1936). *Testability and Meaning*. Philosophy of Science, 3(4), 419-471. 3. Wittgenstein, L. (1953). *Philosophical Investigations*. Blackwell Publishing. 4. Tononi, G. (2008). *Consciousness as Integrated Information: A Provisional Manifesto*. The Biological Bulletin, 215(3), 216-242. 5. Hodgkin, A. L., & Huxley, A. F. (1952). *A Quantitative Description of Membrane Current and its Application to Conduction and Excitation in Nerve*. The Journal of Physiology, 117(4), 500-544.