Monday 25 July 2022

‘Philosophical Zombies’: A Thought Experiment

Zombies are essentially machines that appear human.

By Keith Tidman

Some philosophers have used the notion of ‘philosophical zombies’ in a bid to make a point about the source and nature of human consciousness. Have they been on the right track?


One thought experiment begins by hypothesising the existence of zombies who are indistinguishable in appearance and behaviour from ordinary people. These zombies match our comportment, seeming to think, know, understand, believe, and communicate just as we do. Or, at least, they appear to. You and a zombie could not tell each other apart. 


Except, there is one important difference: philosophical zombies lack conscious experience. Which means that if, for example, a zombie was to drop an anvil on its foot, it might give itself away by not reacting at all or, perhaps, very differently than normal. It would not have the inward, natural, individualised experience of actual pain the way the rest of us would. On the other hand, a smarter kind of zombie might know what humans would do in such situations and pretend to recoil and curse as if in extreme pain. 


Accordingly, philosophical zombies lead us to what’s called the ‘hard problem of consciousness’, which is whether or not each human has individually unique feelings while experiencing things – whereby each person produces his or her own reactions to stimuli, unlike everyone else’s. Such as the taste of a tart orange, the chilliness of snow, the discomfort of grit in the eye, the awe in gazing at ancient relics, the warmth of holding a squirming puppy, and so on.


Likewise, they lead us to wonder whether or not there are experiences (reactions, if you will) that humans subjectively feel in authentic ways that are the product of physical processes, such as neuronal and synaptic activity as regions of the brain fire up. Experiences beyond those that zombies only copycat, or are conditioned or programmed to feign, the way automatons might, lacking true self-awareness. If there are, then there remains a commonsense difference between ‘philosophical zombies’ and us.


Zombie thought experiments have been used by some to argue against the notion called ‘physicalism’, whereby human consciousness and subjective experience are considered to be based in the material activity of the brain. That is, an understanding of reality, revealed by philosophers of mind and neuroscientists who are jointly peeling back how the brain works as it experiences, imagines, ponders, assesses, and decides.


The key objection to such ‘physicalism’ is the contention that mind and body are separable properties, the venerable philosophical theory also known as dualism. And that by extrapolation, the brain is not (cannot be) the source of conscious experience. Instead, it is argued by some that conscious experience — like the pain from the dropped anvil or joy in response to the bright yellow of fields of sunflowers — is separate from brain function, even though natural law strongly tells us such brain function is the root of everyone's subjective experience.


But does the ‘philosophical zombie’ argument against brain function being the seed of conscious experience hold up?


After all, the argument that philosophical zombies, whose clever posing makes us assume there are no differences between them and us, seems problematic. Surely, there is insufficient evidence of the brain not giving rise to consciousness and individual experience. Yet, many people who argue against a material basis to experience, residing in brain function, rest their case on the notion that philosophical zombies are at least conceivable.


They argue that ‘conceivability’ is enough to make zombies possible. However, such arguments neglect that being conceivable is really just another expression for something ‘being imaginable’. Isn’t that the reason young children look under their beds at night? But, is being imaginable actually enough to conclude something’s real-world existence? How many children actually come face to face with monsters in their closets? There are innumerable other examples, as we’ll get to momentarily, illustrating that all sorts of irrational, unreal things are imaginable  in the same sense that they’re conceivable  yet surely with no sound basis in reality.


Proponents of conceivability might be said to stumble into a dilemma: that of logical incoherence. Why so? Because, on the same supposedly logical framework, it is logically imaginable that garden gnomes come to life at night, or that fire-breathing dragons live on an as-yet-undiscovered island, or that the channels scoured on the surface of Mars are signs of an intelligent alien civilisation!


Such extraordinary notions are imaginable, but at the same time implausible, even nonsensical. Imagining something doesn’t make it so. These ‘netherworld notions’ simply don’t hold up. Philosophical zombies arguably fall into this group. 


Moreover, zombies wouldn’t (couldn’t) have free will; that is, free will and zombiism conflict with one another. Yes, zombies might fabricate self-awareness and free will convincingly enough to trick a casual, uncritical observer — but this would be a sham, insufficient to satisfy the conditions for true free will.


The fact remains that the authentic experience of, for example, peacefully listening to gentle waves splashing ashore cannot happen if the complex functionality of the brain were not to exist. A blob that only looks like a brain (as in the case for philosophical zombies) would not be the equivalent of a human brain if, critically, those functions were missing.

It’s those brain functions that, contrary to theories like dualism, assert the separation of mind from body, that make consciousness and individualised sentience possible. The emergence of mind from brain activity is the likeliest explanation of experienced reality. Contemporary philosophers of mind and neuroscientists would agree on this, even as they continue to work jointly on figuring out the details of how all that happens.

The idea of philosophical zombies existing among us thus collapses. Yet, very similar questions of mind, consciousness, sentience, experience, and personhood could easily pop up again. Likely not as recycled philosophical zombies, but instead, as new issues arising longer term as developments in artificial intelligence begin to match and perhaps eventually exceed the vast array of abilities of human intelligence.



Thomas O. Scarborough said...

I have a friend, a professional inventor—of whom there are comparatively few in this world. He tested something with a lonely old woman—which changed the course of his career. He designed a little device which, on the basis of various environmental inputs, kept a running commentary going. Eventually, his device failed. The old woman was greatly distressed. Now he designs comfort robots for the elderly.

This raises the question, Does it matter, whether we have before us a philosophical zombie or not? Not to speak of zombies of other kinds, or in other respects! My own wife may perhaps be a zombie at times. And as in the case of the old woman, I may imagine that the zombie is a sentient being.

In my metaphysics, I raise a question. The problem, traditionally—which people refuse to let die—is that a consciousness A has a causal effect on an object B. Here, we have defined cause A and effect B. Additionally, we claim (if we believe it) that some mysterious relation exists between them.

Now consider any statement at all, to the effect that A caused B. As best I can see, one is dealing with very much the same as consciousness A and object B. One defines A and defines B, and connects them by some relation, again mysterious.

One may object: Mysterious?! It was my neurons which moved my fingers! Yet how? And then how? Examine the relations, and there really is no basis for conscious action—I think!

Put it this way, I question whether we have got beyond the problem of Descartes—rather, the problem which he created. Some have passed beyond this by stating, as did e.g. Ernst Mach, ‘There is no cause nor effect in nature.’ There, I think, lies the problem and the solution: our concept of causality.

Keith said...

Thank you, Thomas, for a very interesting take on the topic of the essay. Your response makes for an interesting read.

Here is Mach’s full quote, which I offer only because I believe it provides important context. My takeaway is that he seemed to view nature as an undifferentiated whole: “There is no cause nor effect in nature; nature has but an individual existence; nature simply is.”

I disagree with Mach, however, as to his argument regarding the supposed “individual existence” and supposed resulting absence of cause and effect. To my mind, there are myriad examples to the contrary: Like, for example, when, in 1919, Sir Arthur Eddington’s photographs of the sun’s eclipse confirmed that light (in this case, from other stars) is bent by the gravity related to massive objects. That, I believe, was a demonstration of cause and effect.

That being said, as clearly smart as Mach was as both a physicist and philosopher, he was surely mortal. See, for example, this comment: “I can accept the theory of relativity as little as I can accept the existence of atoms and other such dogmas.” One might suggest Mach got caught in the netting of his own dogma.

Martin Cohen said...

"…extraordinary notions are imaginable, but at the same time implausible, even nonsensical. Imagining something doesn’t make it so. These ‘netherworld notions’ simply don’t hold up."

My takeaway from this is that Keith is returning to a kind of "Logical Positivist" view of the universe. Nothing exists unless it can be measured, demonstrated empirically – or is logically necessary. So out goes freewill, consciousness, ethics (for starters) but also maybe time and cause and effect. As Mach was saying!

I think all these things are actually human constructs, and only have a weak claim to being real. But equally, they are as real as everything else around us.

Thomas O. Scarborough said...

Ernst Mach: 'I can accept the theory of relativity as little as I can accept the existence of atoms and other such dogmas.' Now suppose that Mach was right ...

I like the context that you (Keith) provide for Mach. His view is my view also. 'Nature has but an individual existence; nature simply is.' Bertrand Russell said something along similar lines (although he didn't seem to draw a lesson from it): 'If the inference from cause to effect is to be indubitable, it seems that the cause can hardly stop short of the whole universe. So long as anything is left out, something may be left out which alters the expected result.'

Now if Mach should be correct, the big question is surely: what causes things? or is the very question mistaken?

Keith said...

“Logical positivist,” Martin? I’ll start packing my bags for Vienna. As for the “measured, demonstrated empirically — or is logically necessary” angle, my take on the things you refer to — consciousness, free will, imagination, and, yes, even notions of ethics — is that they all are products of complex brain function.

Agreed, in that sense, those four things cited are real, but they don’t somehow exist ethereally apart from brain activity. Collaboration between neuroscientists and philosophers of mind will eventually tease out the roots of the neurophysiological activity that makes all that happen. No dualism.

Meanwhile, I think my example about a massive body, like our sun, being shown to bend light from background stars — which Einstein’s theory of general relativity had predicted — was evidence that cause and effect exist as an independent reality within the universe. Cause and effect don’t depend on observation. I reject Mach’s rejection.

In my example in an earlier comment, all that Eddington did was to *demonstrate* the reality of light bending as it passes by a massive body. There’s no pretense that reality of cause and effect depend on observation. The bending would happen irrespective of Eddington. As would, in my opinion, innumerable other examples.

As for “human constructs,” like the monster cuegle from folklore, they do exist, but a reality that exists only within the inner imaginings. Again, as products of neurophysiological activity, for sure. But the cuegle doesn’t somehow slither out of imagined reality into a state of physical reality — in a reality same as that of a tomato (unless it’s just an imagined tomato, of course).

I can’t wait for the rich pastries of Vienna.

Post a Comment