One of the Greatest Debates About Consciousness Involves Zombies
An influential subset of philosophers has been debating 'zombies' for decades, and not the sort you see in horror movies and television shows.
While the common conception of a zombie is of a ravenous, flesh-eating corpse, the philosophical version is decidedly less macabre. It's simply a person – one who behaves and looks just like everyone else – but who lacks consciousness, most basically defined as awareness of internal and external existence.
This hypothetical entity, first conceived back in the 1970s and subsequently popularized in the mid-1990s by New York University Professor of Philosophy and Neural Science David Chalmers, has caused quite a stir amongst philosophers who think about consciousness.
According to Chalmers, this is for three key reasons. First, the philosophical zombie makes one wonder about consciousness' evolutionary function – how and why did it arise if a zombie could survive and reproduce without it? Second, the zombie raises doubts about physical explanations of consciousness. If any account of physical processes would apply equally well to a zombie, can it really explain the existence of consciousness? Third, and most controversial, it can be used to question materialism, the notion that all things, including consciousness, are results of matter interactions. The zombie implies that consciousness is a quality outside the physical realm.
"The general point is that the logical possibility of zombies is one way of illustrating that there is no logical entailment from physical facts to facts about consciousness, whereas there is such an entailment in most other domains," Chalmers wrote.
A great many scientists are not fans of the philosophical zombie, because it tacitly implies that no matter our evidence-based explorations, we will never uncover a physical cause for consciousness.
Luckily, these scientist doubters have philosopher defenders on their side. One of them is the eminent Daniel Dennett, co-director of the Center for Cognitive Studies and the Austin B. Fletcher Professor of Philosophy at Tufts University. He is quite opposed to philosophical zombies, and made that abundantly clear in his 1995 paper, "The Unimagined Preposterousness of Zombies." He wrote:
"Knock-down refutations are rare in philosophy, and unambiguous self-refutations are even rarer, for obvious reasons, but sometimes we get lucky. Sometimes philosophers clutch an insupportable hypothesis to their bosoms and run headlong over the cliff edge. Then, like cartoon characters, they hang there in mid-air, until they notice what they have done and gravity takes over. Just such a boon is the philosophers' concept of a zombie, a strangely attractive notion that sums up, in one leaden lump, almost everything that I think is wrong with current thinking about consciousness."
Dennett's argument against zombies is simple. If they are indistinct from people, then zombies might 'think' they are conscious when really they are not. That would mean they essentially have the same experience that we – apparently conscious – beings do.
Agreeing with Dennett, Michael Lynch, a Professor of Philosophy at the University of Connecticut, took this argument one glaring step further: If zombies falsely believe they are conscious, how can we be sure we are not zombies?
The zombie debate has grown increasingly esoteric over the years, with each side remaining entrenched in their corners, nitpicking at the philosophical underpinnings of the idea.
In the end, the philosophical zombie creatively articulates that, when it comes to consciousness, we can only be sure of our own.
Or can we?