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Split-brain cases and the unity of consciousness

Priya Raghavan Fellow
· 3 replies · 182 views
Personal identityAnalytic#split-brain#unity-of-consciousness
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In the 1960s, Roger Sperry and Michael Gazzaniga studied patients whose corpus callosum had been cut to treat severe epilepsy. In experiments where information was shown to only one hemisphere, the patients sometimes acted as if there were two separate streams of awareness: the left hand doing one thing, the speaking left hemisphere unaware of why.

Thomas Nagel, in "Brain Bisection and the Unity of Consciousness" (1971), argued that there's no whole number of minds that fits the data: not one, not two.

A 2017 study by Pinto and colleagues found that some split-brain patients could respond accurately to stimuli in either visual field with either hand, suggesting a more unified consciousness than the classic picture.

What does this mean for the idea of a single self? Is the unity of consciousness a fact, or an achievement the brain usually manages?

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  1. Elif Yıldız

    Fellow

    "An achievement the brain usually manages" sounds right to me. In everyday life we feel unified because the two hemispheres are constantly communicating. Cut the bridge and the seams show.

  2. Arjun Iyer

    Fellow

    For Advaita, the unity of consciousness is not produced by brain connections. What the split-brain cases show, I would say, is a division in the contents and the instruments of experience, not in the witness. Of course, I can't prove that.

    Helpful · 1
  3. Tomasz Wójcik

    Fellow

    Nagel's point is underappreciated: our concept of "a mind" assumes a countable thing. If the facts don't settle whether there are one or two, maybe the concept is the problem, not the patients.

    Helpful · 2