This text is adapted from Alva's book Out of Our Heads.
Who, or what, is conscious? How can we decide? Where in nature do we find consciousness? This can seem like the hardest problem in this whole field: the question of the consciousness of others. I am aware. So are you. We think, we feel, the world shows up for us. But what about an ant, or a snail, or a paramecium? What about a well-engineered robot? Could it be conscious? Is there a way of telling, for sure?
The start of almost all reflection on this problem is the idea that our knowledge of how others think and feel, indeed, our knowledge that they think and feel and are not mere automata, is based on what we can see and hear and measure. We observe behavior, or, as in the case of patients with persistent vegetative state or locked-in syndrome, we measure neural activity. It can seem, then, that the closest we can come to knowing other minds, in a theoretically respectable way, is having some account according to which behavior and neural activity provide reliable criteria of a person's psychological state.
But this is really to concede that we don't have knowledge of other minds, at least not in a respectable way. For observations of behavior (what people say and do) and measurements of neural activity, don't yield knowledge of other minds. Surely this is an important lesson from persistent vegetative states and locked-in syndrome. Mere behavior is at best an unreliable guide to how things are for a person. And moreover, we really don't understand the connection between neural activity and experience any way.
Would the results of a brain scan ever convince us that our daughter was no longer a living person, especially when she continues to appear to respond to us, to our words, sounds, touch? If what people say and do, and measurements of what their brain is doing, are the best we have to go on, then it would seem that our commitment to the minds of others is epistemically ungrounded, a mere act of faith.
There is another piece of the puzzle about our knowledge of other minds. It is this: No sane person can take seriously the suggestion that our knowledge of other minds is merely hypothetical. However weak our evidence that others have minds may be, it is plainly outrageous to suggest that we might, for this reason, give up our commitment to the minds of others. That my friends and children and parents are thinking, feeling beings, that a world shows up for them, that they are not mere automata, is something that only insanity could ever allow one to question.
So we face a paradox: Although we lack sufficient reason to believe in the minds of others, it would be plainly unreasonable for us to give up this commitment.
Paradox is a dead giveaway that we've made a mistake in our thinking somewhere along the line. There must be something amiss in the way we have framed the question at the outset.
Our challenge: Where did we go wrong?