What If Your Visual Cortex Were Replaced? | Arnold Zuboff

Closer To Truth
Closer To TruthJun 5, 2026

Why It Matters

If correct, Zuboff’s argument undercuts materialist intuitions that consciousness depends on specific biological tissues and supports the view that artificial or nonbiological systems could instantiate genuine experience, with major implications for neuroscience, AI ethics, and mind-uploading debates.

Summary

Philosopher Arnold Zuboff argues for functionalism using a thought experiment: if a scientist replaced his right visual cortex with a device that preserved the same input-output relations, his visual experience and behavior would remain unchanged. From this he concludes that qualia—the subjective character of experience—are determined by functional role and relations to the rest of the mind, not by the material substrate. Zuboff acknowledges complexities when replacing larger or more integrated mental systems but maintains the core claim that functional equivalence suffices for preserving conscious experience. He positions this as a decisive rebuttal to views that intrinsic biological properties alone ground qualia.

Original Description

Would your conscious experience remain the same if part of your brain were replaced by a machine?
Arnold Zuboff argues that if an artificial device preserved the same functional relationships as a biological brain region, then the resulting conscious experience — including qualia — would have to remain unchanged.
1:07 The Argument for Functionalism
1:42 Replacing the Visual Cortex
3:54 Why Functional Equivalence Preserves Experience
7:04 Can Functionalism Explain Qualia?
8:30 Replacing More and More of the Brain
Arnold Zuboff is an American philosopher known for his work on personal identity, consciousness, and probability. He took his PhD at Princeton in 2009 under Thomas Nagel and spent most of his academic career at University College London.
More from Arnold Zuboff on Closer To Truth:
* Understanding Consciousness - Closer To Truth - Core Topic: https://www.youtube.com/playlist?list=PLFJr3pJl27pJKWEUWv9X56y_ut3xwFDv1
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