Philosophers have long worried whether it is ever really possible to know how things are, internally, with another.
After all, we are confined to the external — to mere behavior, or perhaps to behavior plus measurements of brain activity. But the thoughts, feelings, images, sensations of another person, these are always hidden from our direct inspection.
The situation of doctors facing unresponsive victims of brain injury is a terrifying real-world example of the fact that we our locked out of the minds of another.
Consider the remarkable report, published Monday in Current Biology and discussed here, that a team in France has enabled a patient who has languished for 15 years in a vegetative state, to show, as they claim, a marked improvement in his levels of consciousness. They achieved this by means of the direct and sustained stimulation of the vagus nerve.
As Dr. Angela Sirigu, one of the team leaders, explains by email, the results are dramatic:
"After VNS [vagus nerve stimulation] the patient could respond to simple orders that were impossible before (to follow an object with his gaze, to turn the head on the other side of the bed on verbal request). His ability to sustain attention, like staying awake when listening to his therapist reading a book, greatly improved as reported by the mother. After stimulation, we found also responses to 'threat' that were absent before implantation. For instance, when the examiner's head suddenly approached to the patient's face, he reacted with surprise by opening the eyes wide, a reaction which indicates that he was fully aware that the examiner was too close to him."
Without wishing to cast any doubt whatsover on these remarkable findings, it is surely not insignificant that Sirigu cites the patient's mother when remarking on his improved ability to sustain attention to a book being read by a therapist. Who else, but a loved one, will have the patience, the concern, the resources to discern what may be subtle and maybe also transient behavioral responses? And of course, by the same token, who more than a grieving mother has more invested in seeing life and recovery in the flicker of an eye, or the turn of the head?
As a matter of fact, Sirigu and her team also report striking neurophysiological indicators of improvement. She writes via email:
"Most importantly our results show major changes at the brain level. We found that the theta EEG signal, a brain rhythm previously shown to distinguish vegetative from minimally conscious state patients, significantly increased after VNS in areas important for movement, body sensations and awareness. Interestingly, VNS also increased communication between these regions through a strengthening of their functional connectivity. Finally, a Pet-scan exam showed extensive increases in metabolic activity (glucose consumption) over cortical and subcortical regions after VNS."
These are important findings and it is clear that they are signs of improvement in this one patient.
But it is remarkable, and hard to ignore, that these measures do very little to give us the insight we really crave: What does this patient experience, or feel or sense? Is he in fact conscious at all?
Some years ago, as my young son was about to be wheeled off to have an operation, I asked the anesthesiologist if he could reassure me that my kid would feel no pain during the procedure. "I'll watch his face and monitor his blood pressure and pulse rate," was the doctor's only partly reassuring reply. I remember wondering: "Can't we do better than that?"
Maybe not. Maybe that's the best we can do.
And, of course, the ethical stakes are high. What's at stake is making sure we give the appropriate care to patients. It may be that that's the best we can do, but we are morally obliged to try to do better.
Alva Noë is a philosopher at the University of California, Berkeley, where he writes and teaches about perception, consciousness and art. He is the author of several books, including his latest, Strange Tools: Art and Human Nature (Farrar, Straus and Giroux, 2015). You can keep up with more of what Alva is thinking on Facebook and on Twitter: @alvanoe