When a neuroscientist observes the activation of the V4 area of the cortex, which processes color information, upon presentation of a red stimulus, the subjective experience of red remains inaccessible to scientific measurement. This gap between objective neural correlation and subjective qualia—the sensation of redness itself—is the essence of what philosopher David Chalmers called the hard problem of consciousness.
The hard problem, formulated by Chalmers in 1995, asks a different question than neuroscience: Why do physical processes in the brain give rise to subjective experience? Neuroscience successfully describes how neurons activate, how information is processed, but it does not explain—and cannot explain using standard reductionist methods—why these correlates are accompanied by this particular quality of experience, rather than another, or its complete absence.
Within this philosophical chasm lies an unexpected parallel with ancient Indian philosophy, Advaita Vedanta. This school of thought, tracing back to the teachings of Adi Shankara in the 8th century, proposes a fundamentally different ontology: it is not matter that generates consciousness, but a single, unified consciousness (Brahman) that is the foundation of all reality. Color, in this understanding, is neither a property of an external object nor merely a result of neural processing, but a manifestation of this unified consciousness, in which the division between subject and object remains an illusion.
The juxtaposition of these two approaches reveals a profound tension between the reductionist methodology of modern science and an alternative non-dual perspective. Reductionism assumes the primacy of matter and seeks to explain consciousness in terms of physical processes. Advaita, however, inverts the hierarchy: consciousness is primary, and matter is derivative of it or even illusory from an absolute point of view.
However, there is a serious objection from the philosophicalแนวทาง known as illusionism. Proponents of this approach, such as Daniel Dennett and Keith Frankish, argue that qualia are not real properties but an error of introspection, an artifact of our way of thinking about consciousness. If they are correct, then the non-dual interpretation loses one of its supporting pillars: the experience of red is not a genuine qualitative property of consciousness that requires an alternative explanation. To refute the non-dual approach would require demonstrating that the experience of color is fully reducible to functional or informational processes without any residue of unexplained subjectivity.
Imagine an artist mixing paints on a palette. Each stroke seems to them not just a specific wavelength, but a moment when consciousness animates the color, gives it quality, imbues it with meaning. In neuroscience, this corresponds to the activation of specific neural modules in V4 and related cortical areas. In the ontology of Advaita Vedanta, it is the manifestation of Brahman through the lens of individual consciousness. The analogy illustrates why a mechanistic description of neural processes does not exhaust the phenomenon of experiencing color: it describes only the instruments, not the music they produce.
The philosophical study of qualia, expanded to include subtle insights from Eastern philosophy, suggests the possibility of a deeper dialogue between science and spiritual traditions. Not by abandoning the scientific method, but by reconsidering its limits of applicability. Neuroscience and non-dual philosophy can complement each other if we abandon the assumption of matter's primacy as the sole foundation of reality.
This compels a reconsideration not only of philosophical theories of consciousness but also of methodology itself—acknowledging that subjective experience requires special attention that extends beyond standard reduction to physical processes.
