At Mind Matters, neuroscientist Michael Egnor asks, “DOES THE ABILITY TO THINK DEPEND ON CONSCIOUSNESS?” His answer: no. “In my view, the capacity for thought does not depend on consciousness. The term ‘consciousness’ is at best meaningless and at worst an impediment to understanding the mind.” If true, this would have disturbing implications, not least for those who undergo surgery:

When I was a medical student, my anesthesiology professor said that the fundamental goals of good anesthesia are “analgesia and amnesia.” This shocked me: I asked him, “What about unconsciousness? Doesn’t anesthesia make patients unconscious during surgery?” He replied that “unconscious” really has no medical meaning, and inability to feel pain and amnesia for the surgery are the only real measurable effects of anesthesia. We don’t know — and can’t know — if patients are “conscious” during surgery. We only know what behavior tells us: they show no physiological signs of pain and they have no memory of the event. The science of anesthesiology has nothing corresponding to “unconscious” — it merely monitors and strives for analgesia and amnesia. [Emphasis added.]

Think about that next time you are put under general anesthesia, which I hope neither you nor I will be anytime soon. You will never know if you were “conscious” while in that state. I find that a bit terrifying. More:

Here is a personal example: I had spinal anesthesia for ankle surgery a decade ago. I did not have general anesthesia. I was awake and speaking with the anesthesiologist throughout the operation but I felt no pain (from the spinal anesthetic) and I had no memory whatsoever of the procedure (from the sedative they gave me, which has strong amnestic effects). As far as I was concerned, it was the same as a general anesthetic — I felt nothing and remember nothing. It was the same as being unconscious, which I was not. I was wide awake and conversing with the anesthesiologist (who is a friend of mine and reassured me that I said nothing embarrassing!). Without pain or memory, I was, for his purposes, unconscious, even though I was (they tell me) awake and talking the whole time. Subjectively I couldn’t distinguish analgesia and amnesia from unconsciousness. So what does “consciousness” mean?

Read the rest at Mind Matters, published by Discovery Institute’s Walter Bradley Center for Natural and Artificial Intelligence.