Chapter 14
The Anesthesia Argument
One of the most powerful everyday demonstrations that consciousness is produced by brain functioning, and that it can be interrupted and restored, is the experience of general anesthesia.
When a person undergoes general anesthesia, their consciousness appears to be completely eliminated, suppressed below the threshold of detectability. There is no experience of passing time, no dreaming (though studies using the bispectral index (BIS) and isolated forearm technique have found evidence of residual neural processing under certain protocols), and no awareness of the surgical room. From the patient's perspective, there is absolutely nothing.
What Anesthesia Teaches Us
Anesthesia teaches us several things that are crucial for our argument:
First, consciousness is not a permanent property of the body. A body can exist — can even be alive, with a functioning heart and circulating blood — without producing consciousness. Consciousness is something the brain does when it functions in the right way, not something the brain has as an intrinsic property. Stop the right functioning (with anesthetic drugs), and consciousness stops. Restore the right functioning, and consciousness returns.
Second, gaps in consciousness do not affect identity. You are the same person after anesthesia as before, despite the gap. Your ixperiencitness is unchanged, your memories (up to the point of anesthesia) are intact, and your personality is the same. The gap, from the perspective of your conscious identity, might as well not have happened.
The Anesthesia Extension Argument
Now let me extend the anesthesia argument in a way that reveals its full power.
Imagine you are put under general anesthesia. While you are unconscious, a surgeon makes changes to your brain. Perhaps they add some neurons, alter some connections, modify the balance of neurotransmitters. When you wake up, you are slightly different — perhaps a bit smarter, or with slightly different emotional responses, or with a few memories added or removed.
Are you still you? Most people would say yes, especially if the changes are small. You are a modified version of yourself, but still recognizably you — still possessing your ixperiencitness, perhaps slightly altered.
Key Terms in This Chapter
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The remaining text (examples, counter-arguments, and longer connective passages) is in the book.