"Self-Portrait"
Œuvre de 1968 du peintre
From the publication of Stevan Harnad
"Why and how we are not zombies"
From Journal of Consciousness Studies, Vol. 1, Num. 2, pp. 164, (1994)
Let us not mince words. The difference between something that is and is not conscious is that something's home in something that's conscious, something experiencing experiences, feeling feelings, perhaps even, though not necessarily, thinking thoughts. Don't be lured into details about "self-awareness" and "intentionality." If there's something home in there, something hurting when pinched, then that's a mind and we are faced squarely with two age-old philosophical problems:.
The first is: How can we know whether or not something's home in there? We aren't mind-readers. Not even a brain surgeon can guarantee that a patient is conscious. This is called the "other-minds" problem, and it's important to note that it is unlike any other problem in science having to do with the existence or reality of something that is unobservable. Quarks, like consciousness, cannot be observed directly, but there are many things that follow from quarks' existing or not existing, and those things can be observed. Does anything follow from the existence of consciousness, that would not follow just as readily if we were all Zombies who merely acted exactly as if they were conscious?.
Think about it: Zombies who acted exactly as if they were conscious: Acted for how long? Well, for a lifetime obviously. And what does "exactly" mean? It means that there is no way to tell them apart from one of us based on anything they do. Zombies are functionally equivalent to and functionally indistinguishable from ourselves.
"So cut them apart," you say, "and check what's inside. If it's different from what's in us, that's still an observable difference, and we could conclude from that that they were just unconscious Zombies."
But could we really draw that conclusion if they were made of different stuff? What if they came from another planet: Would the fact that their innards were different be enough to convince you that they didn't feel pain when they were pinched and screamed? Would you yourself like to submit to such a verdict on another planet?
Or would you feel more comfortable pronouncing such a verdict if they didn't come from another planet, but were built in a lab here on earth? Is there something about that that guarantees that their screams are not genuine? If you feel there is, then you must feel that you know something about the solution to the second philosophical problem, the mind/body problem:
What is consciousness? Let us assume that, whatever it is, it isn't an extra "force" in nature, on a par with electricity or gravity, for otherwise all our thoughts would be telekinetic, mind moving matter, and high energy psychic forces would be duelling with their "duals," high energy physics forces, not only in the world as a whole, but in the Academy in particular, with the prize being the truth or falsity of the laws of energy conservation and perhaps even causality itself.
So we will assume, instead, that consciousness is not an autonomous force, but some property or aspect of the ordinary physical forces we already know. If so, then it is incumbent on anyone who thinks he can tell the Zombie from the real thing that he be able to say what this property is. This is a notoriously difficult thing to do; in fact, I'm willing to bet it's impossible, and will even say why:
Pick a property. Any property. It can be anatomical, physiological, chemical or even "functional." Suppose that that property is what determines whether or not something is conscious. Now answer the following two questions:
(1) How could you ever determine whether that supposition -- that that's the property that distinguishes conscious things from unconscious ones -- was correct? That's the other-minds problem again.
But now let's suppose that the supposition -- that that's the property that distinguishes conscious things from unconscious ones -- was, miraculously, true, even though there was no way we could know it was true:
(2) In what, specifically, would its truth consist? What is it that something would lack if it lacked consciousness yet had the property you picked out? For if you pick anything other than consciousness itself as the thing it would lack if it lacked that property that was supposed to be the determinant of consciousness (which would be a bit circular), then one can always say: why can't it have that property without the consciousness? And no one has even the faintest inkling of what could count as a satisfactory answer to that question.
[...]
Actually, I think scientific mind-theory is better described as reverse bioengineering: Ordinary engineering applies basic physics and engineering principles to the design of systems with certain functional capacities that are useful to us [bridges, ovens, planes, computers], whereas a scientific theory of mind would first have to successful second-guess what gives creatures like us, already ready-made by the Blind Watchmaker, our functional capacities.
[...]
I really think that the task of generating our full Zombie capacity probably already narrows the degrees of freedom enough to exclude all nonconscious candidates. I draw some solace, for example, from the fact to which I have already drawn attention, namely, that the "forward engineer" (the Blind Watchmaker) whose work we are reverse engineering had nothing stronger to go by either. But does this mean that the mind/body problem is really just another example of scientific underdermination that will be settled by whatever candidate makes it to the home stretch at the end of the day?
Not quite. For that would be all there was to it if consciousness were like quarks, that other example of an unobservable that I mentioned earlier. One can, without too much loss of sleep, accept that if the winning theory says there are quarks -- because with quarks it can predict and explain all the observable data, whereas without them it can't -- then it's safe to accept that there are indeed quarks.
But I have to remind you that our complete reverse engineering theory, the one that generates our full Zombie capacity, will be entirely mute about consciousness, and will be just as capable of predicting and explaining all the observable data with or without the supposition that the Zombie is conscious.
Perhaps another way of putting it is that the complete Zombie theory will explain all the data except one: The fact of the existence of consciousness itself. This fact is at the heart (or rather the mind) of the very idea of "observation," and it's a fact that each of us can "observe" to be true in his own particular case.
So clearly the Zombie theory has left something out. Hence there is still something different here, something special about the mind/body problem, and something that eludes a scientific theory of mind unlike anything analogous in a scientific theory of matter. Maybe it's safe to assume that consciousness will somehow piggyback on Zombie capacity; maybe not. It might be some consolation that if it doesn't, we can never hope to be the wiser. But I think it's nothing to lose sleep about, at least not for a long time to come.
What is consciousness? Let us assume that, whatever it is, it isn't an extra "force" in nature, on a par with electricity or gravity, for otherwise all our thoughts would be telekinetic, mind moving matter, and high energy psychic forces would be duelling with their "duals," high energy physics forces, not only in the world as a whole, but in the Academy in particular, with the prize being the truth or falsity of the laws of energy conservation and perhaps even causality itself.
So we will assume, instead, that consciousness is not an autonomous force, but some property or aspect of the ordinary physical forces we already know. If so, then it is incumbent on anyone who thinks he can tell the Zombie from the real thing that he be able to say what this property is. This is a notoriously difficult thing to do; in fact, I'm willing to bet it's impossible, and will even say why:
Pick a property. Any property. It can be anatomical, physiological, chemical or even "functional." Suppose that that property is what determines whether or not something is conscious. Now answer the following two questions:
(1) How could you ever determine whether that supposition -- that that's the property that distinguishes conscious things from unconscious ones -- was correct? That's the other-minds problem again.
But now let's suppose that the supposition -- that that's the property that distinguishes conscious things from unconscious ones -- was, miraculously, true, even though there was no way we could know it was true:
(2) In what, specifically, would its truth consist? What is it that something would lack if it lacked consciousness yet had the property you picked out? For if you pick anything other than consciousness itself as the thing it would lack if it lacked that property that was supposed to be the determinant of consciousness (which would be a bit circular), then one can always say: why can't it have that property without the consciousness? And no one has even the faintest inkling of what could count as a satisfactory answer to that question.
[...]
Actually, I think scientific mind-theory is better described as reverse bioengineering: Ordinary engineering applies basic physics and engineering principles to the design of systems with certain functional capacities that are useful to us [bridges, ovens, planes, computers], whereas a scientific theory of mind would first have to successful second-guess what gives creatures like us, already ready-made by the Blind Watchmaker, our functional capacities.
[...]
I really think that the task of generating our full Zombie capacity probably already narrows the degrees of freedom enough to exclude all nonconscious candidates. I draw some solace, for example, from the fact to which I have already drawn attention, namely, that the "forward engineer" (the Blind Watchmaker) whose work we are reverse engineering had nothing stronger to go by either. But does this mean that the mind/body problem is really just another example of scientific underdermination that will be settled by whatever candidate makes it to the home stretch at the end of the day?
Not quite. For that would be all there was to it if consciousness were like quarks, that other example of an unobservable that I mentioned earlier. One can, without too much loss of sleep, accept that if the winning theory says there are quarks -- because with quarks it can predict and explain all the observable data, whereas without them it can't -- then it's safe to accept that there are indeed quarks.
But I have to remind you that our complete reverse engineering theory, the one that generates our full Zombie capacity, will be entirely mute about consciousness, and will be just as capable of predicting and explaining all the observable data with or without the supposition that the Zombie is conscious.
Perhaps another way of putting it is that the complete Zombie theory will explain all the data except one: The fact of the existence of consciousness itself. This fact is at the heart (or rather the mind) of the very idea of "observation," and it's a fact that each of us can "observe" to be true in his own particular case.
So clearly the Zombie theory has left something out. Hence there is still something different here, something special about the mind/body problem, and something that eludes a scientific theory of mind unlike anything analogous in a scientific theory of matter. Maybe it's safe to assume that consciousness will somehow piggyback on Zombie capacity; maybe not. It might be some consolation that if it doesn't, we can never hope to be the wiser. But I think it's nothing to lose sleep about, at least not for a long time to come.
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