The Zombie Menace

No, not that kind of zombie. I want to talk about a kind that behaves like a normal human being, but isn't: something that has been called a "philosopher's zombie." You could also think of this kind of zombie as a highly sophisticated artificial intelligence (AI), one that's capable of passing the Turing test. It is a being that fools us into thinking that it is conscious based on its behavior, but that has no real conscious awareness. It is a very good mimic of behavior, to the point where it can even make verbalizations that seem to describe inner experience: Statements such as "I don't feel like a zombie."

I described philosophers' "zombie problem" once before, in a post about free will, but it's actually more encompassing than whether we control our actions. A true philosopher's zombie not only has no control over its behavior, it also has no internal experiences of its world. It looks, acts, and talks like we expect from a human being, but it doesn't have any corresponding internal world. There is nothing "that it is like to be" such a creature. The lights are on, but nobody's home.

Even though most people initially find this idea silly, philosophers have proposed some nuances that make the idea harder to dismiss. A zombie that is able to provide self-referential information about its own internal states can seem much less distinguishable from a person. Consider this example from Daniel Dennett (2014), in which Zeke is a philosopher's zombie:

    YOU: Zeke, do you like me?

    ZEKE: Of course I do. You're my best friend!

    YOU: Did you mind my asking?

    ZEKE: Well, it was almost insulting. It bothered me that you asked.

    YOU: How do you know?

    ZEKE: Hmm. I just recall feeling a bit annoyed or threatened or maybe just surprised to hear such a question from you. Why did you ask?

    YOU: Let me ask the questions, please.

    ZEKE: If you insist. This whole conversation is actually not sitting well with me.

Here, Zeke has the ability not only to respond to questions ("of course I like you"), but also to describe internal states triggered by external stimuli ("surprised to hear such a question") and to access memories of past states ("I just recall feeling a bit annoyed"). Zeke can even make meta-statements about the context and implications of interactions ("this whole conversation is actually not sitting well with me"). Nevertheless, in this example remember that Zeke is a philosopher's zombie (or a robot, if you prefer), and that Zeke has no inner, subjective experiences corresponding to its statements. Zeke is a sophisticated, self-referential algorithm, and that's all. 

Based on this description, philosophers' zombies do seem like a real threat to our understanding of consciousness. I have a pretty strong sense that I am not a zombie -- that it feels like something to be me -- but I'm no longer so convinced that you are not a zombie. You very well could be! We have of course never invented a robot that can pass the Turing test, but it seems plausible that we eventually could.

Once I start down this path in thinking, there seems to be no clear way to differentiate in my day-to-day encounters between "actual people" and philosopher's zombies. The one thing I feel that I can hold onto is the old statement from Rene Descartes, cogito ergo sum, or "I think, therefore I am." In the Cartesian example, the world I see and all of the people in it could be simply an illusion or the torments imposed by a mad god. But I'm still convinced that I (and perhaps I alone) have subjective experiences, and therefore that I am a conscious agent who exists in the world.

Dennett, a materialist, is willing to discard even Descartes' famous cogito. He is willing to say that self-referential awareness and behavior is all that is involved in consciousness, and therefore that even he himself is a philosopher’s zombie. In other words, Dennett argues that what we think we know about our conscious experience of the world is an illusion, that qualia (the properties we perceive, like the "redness" of an apple) do not exist, but are simply language statements made by self-referential zombies like us. In essence Dennett has defined away the very thing that we mean by "consciousness" as simply an internal set of mental behaviors (saying to myself "I feel cold," for example) that is produced by purely physical mechanisms. This kind of zombie menace is in some ways even scarier than the Hollywood brain-eating type. If Dennett is correct, you are one of these zombies already and you have just deluded yourself into believing otherwise. Furthermore, Dennett's argument is quite persuasive if we believe that mental states are always and only the result of concrete physical states -- i.e., that consciousness is a property produced mechanically by the "neural correlates of consciousness" (NCCs). Eventually, once the neural mechanism that produces conscious experiences is explained precisely enough, Dennett argues that we will all turn out to be philosopher's zombies.

So what's the alternative? There are two basic positions in opposition to Dennett's materialism: dualism and idealism. Dualism is the classic religious view that people have two parts - a body and a soul. It is often called Cartesian dualism because it fits well with Descartes' notion that thought is a solid fact even if matter might be an illusion of the senses. In traditional dualist views, the conscious experiencing person is separate from his or her body, a "ghost in the machine" that is attached in some way to the person walking around. The body might be a philosopher's zombie, but the experiencing soul is not. Dualist models are less popular these days simply because so many of the functions once believed to be part of the soul (seeing, thinking, feeling, etc.) have now been pinned down to specific brain structures and processes. The success of materialism in explaining things so far has led to a certain confidence that everything can eventually be explained in materialist terms.

Many philosophers still believe, however, that matter and consciousness are qualitatively different. The materialist view is challenged by what David Chalmers described as the "Hard Problem of Consciousness":

even when we have explained the performance of all the cognitive and behavioral functions in the vicinity of experience—perceptual discrimination, categorization, internal access, verbal report—there may still remain a further unanswered question:  Why is the performance of these functions accompanied by experience? (1995, 202, emphasis in original).

Chalmers suggests that there is no physical reason why it should "feel like something" to perform cognitive functions associated with perceiving, deciding, acting, and so on, if materialism were true. Instead, he says that the simple existence of people’s subjective experiences proves that materialism is false. Chalmers argues for a form of dualism in which consciousness is a sort of "emergent property" of complex systems -- it is not produced directly by the system's operations, but instead arises spontaneously as the system goes about its functions. Another emergent-property view of consciousness is provided by W. Teed Rockwell, who argues that consciousness arises from interactions between the brain, body, and world -- in other words, that you must have a brain in order to be consciousness, but that it's not only in your brain where consciousness resides; in philosophers' technical terminology, the mind "supervenes" on the brain in these models. How this might happen is still unknown, but one proposal comes from Tam Hunt and Jonathan Schooler at the University of California Santa Barbara - that shared vibration between physical objects is the key, as seen in the synchronized neural firings that we measure as human brain waves.  

Chalmers's view has some surprising implications, in particular that any sufficiently complex system will have consciousness emerge from it, meaning that AI systems are not only possible but almost certain. In Chalmers’s view, a robot that can pass the Turing test will not only appear to be conscious, it actually will be! Chalmers’s proposal also means that the universe as a whole, being a complex system, likely has some form of consciousness, as do many other things that we would typically classify as inanimate. Hunt and Schooler's "general resonance theory," if correct, can also be taken as support for this position. Chalmers readily accepts the label of "panpsychism" for his view, in which everything that exists is conscious in some form because consciousness is an emergent property of material things. [It's worth noting that many of these theorists do not consider themselves dualists, because they do believe consciousness emerges in some way from matter. However, each proposes a method by which qualitatively different mental phenomena attach themselves to purely physical ones].

The third perspective, idealism, is in some ways even more counterintuitive to our 21st-century way of thinking. In this view, nothing except mind exists, and our perception that we live in a physical world of objects is in fact an illusion. A contemporary advocate for this position, Bernardo Kastrup, puts it this way: "reality consists of patterns of excitation of a universal mind," ad the physical world we think we see is simply what all that fundamentally mental activity looks like to an observer. A typical expression of Kastrup's view is this: "There is nothing to a whirlpool but water. Yet, we can point at it and say: There's a whirlpool! Analogously, there is nothing to a body but consciousness. Yet, we can point at it and say: there's a body! For exactly the same reason that a whirlpool doesn't generate water, the body-brain system doesn't generate consciousness. Yet, because the image of a process carries valid information about the inner dynamics of the process - just like the colors of flames carry valid information about the microscopic details of combustion - brain activity correlates with subjective experience. ... We don't say that lightning is the cause of atmospheric electric discharge, do we? Lightning is simply what atmospheric electric discharge looks like from the outside. For exactly the same reason, it is absurd to say that neurons cause thoughts, emotions, or perceptions. Neurons are simply what our thoughts, emotions, and perceptions look like when another person observes them" (Kastrup, 2015, p. 13, emphasis in original).

Or, in the idealist view of Donald Hoffman, "objects, shapes, space, and time reside in consciousness. ... Spacetime is your virtual reality, a headset of your own making. The objects you see are your invention. You create them with a glance and destroy them with a blink." There are some clear technical challenges to this view of the relationship between mind and brain: For instance, why do we not have access to one another's experiences? Kastrup argues that all experiences do in fact arise from the activations of one universal mind, and that each of us has separate experiences because we are in fact "alters" dissociated in some way from our true origin within that universal mind. Presumably if the barriers could be removed, a much broader conscious experience would be within our reach. In Kastrup's view, this explains the extraordinary quality of near death experiences, because there's no reason in materialism to expect more intense, meaningful, and impactful experiences from a damaged brain, but every reason for this in idealism. 

Another challenge to idealism comes from the fact that we can't make things happen just by thinking them -- an "objective" world seems to exist that resists our mental efforts. Kastrup dismisses this argument by appealing to the universal mind, which he says is responsible for what seem to us as immutable physical properties of matter. Alternately, in Hoffman's view, the reason things seem solid and real to us is that we all have been shaped by evolution to view our experiences through the same set of lenses -- i.e., in terms of which things will help us and which will harm us, their utility for our survival. We have a shared reality simply because we each have similar needs and instrumental goals. There are differences in these views: Hoffman concedes that there is some reality external to our minds, even though we can never know it, while Kastrup argues that there is no physical world at all external to the conscious experiences we are all having. Idealist philosophers often appeal to quantum physics,in which reality is determined by the perspective of the person observing it; we know from recent research that even the mass of a rock or a chair is simply a manifestation of the Higgs field expressed by its subatomic particles. These developments in physics, the hardest of sciences, do seem to support idealism. As Bishop Berkeley once argued, perhaps if there is no observer, there is no world.

How does research using Two Minds Theory inform these philosophical matters? Only tangentially, because TMT is more concerned with causation -- the origin of behavior -- than with consciousness. But TMT does include the notion of conscious thought, so we can look at whether its view of consciousness fits better with one or another of these philosophical positions. 

First, the conscious mind’s lack of control over many behaviors is a challenge for any model (like cognitive-behavior therapy) that suggests behavior is the result of conscious intention. Philosophers sometimes use the existence of intention-behavior gaps as evidence that consciousness either is an illusion (Dennett) or is an epiphenomenon that exists but doesn't matter (some interpretations of Chalmers). TMT does build on findings from behavioral economics about the ways in which our conscious minds deceive us. Yet Hoffman give a clear explanation for why perceptions can and perhaps must distort reality, because they are designed to convey information about usefulness rather than ground truth. In Kastrup’s idealism, the difficulty arises because of discrepancies between “dissociated alters” of mind like ourselves and the “universal mind” that produces laws of nature. Even a purely idealist view of consciousness, then, can be compatible with the existence of cognitive, perceptual, and behavioral errors. A dualist view certainly can be, as in St. Paul's classic formulation of the intention-behavior gap (Romans 7:15), or Plato's "two horses" view of mind and matter. The mere existence of intention-behavior gaps, then, does not support any particular view of consciousness.

Second, TMT suggests that the Narrative mind is where our reportable conscious experience generally resides, which in general fits with Dennett's view that consciousness consists of ideas and beliefs expressed in behavioral terms through language. But our reportable experience is not the entirety of our experience, and TMT studies show that moment-by-moment thoughts and feelings can actually differ substantially from what people later express in language. This disconnect suggests that consciousness is not only an exercise in language and social positioning, but actually does correlate to some original in-the-moment experience that is later edited and summarized using language. TMT's model of two mental systems with different structures and functions suggests that Dennett's view is too simplistic.

Third, TMT recognizes that there does seem to be something different about the qualia type of experience -- arising from the Intuitive system -- compared to the logic-and-reasoning type of experience that comes out of the Narrative system. Every narrative is a form of abstraction that is separated in some ways from the experiences that gave it birth, in the words of C.S. Lewis an attempt to "catch in our net of successive moments something that is not successive.” This blog has previously explored interesting subjective phenomena like near-death experiences and human echolocation, which are best understood through an Intuitive-mind lens. If qualia are what we mean by consciousness, then consciousness exists primarily in the Intuitive mind. The difference between Intuitive-mind qualia and Narrative-mind logical analysis, both of which TMT recognizes as legitimate modes of thinking, brings to the fore Chalmers's "Hard Problem of Consciousness." Contrary to Dennett, we can't just explain away the feeling of subjective experience in behavioral terms. 

Finally, TMT proposes that consciousness extends at least slightly beyond the Narrative mind, via the conscious control of attention. Some of the most promising applications of TMT have to do with using sensor data to bring momentary experiences into conscious awareness, using mindfulness to extend conscious awareness deeper into the Intuitive mind, or to prompt different in-the-moment experiences using mHealth messages. Even though consciousness is limited in important ways compared to the more automatic workings of the Intuitive mind, we can train ourselves to extend our awareness into at least some aspects of the Intuitive mind, which may open up additional possibilities for behavior. This kind of expansion of consciousness seems more compatible with a dualist explanation, or with an idealist one in which we can under unusual circumstances gain access to mental phenomena not immediately accessible to us. The simple fact that people can consciously focus their attention would seem to argue against Dennett's view that consciousness is only verbal behavior - some additional cognitive resource, attention, seems to exist as "mental stuff" separate from the brain. This simple observation is the core strength of Descartes' dualist maxim, cogito ergo sum.

The zombies are still a threat: It's possible that Dennett is correct, and that even my Intuitive-level perceptions and conscious direction of attention are simply operations of a material brain. But personally I’m not willing to take Dennett’s leap away from the cogito and abandon the idea that my subjective experience exists. It seems more likely to me that some form of dualism applies, although that still leaves me with the Hard Problem of Consciousness to resolve. I'm impressed by the logical simplicity of purely idealist understandings, but not quite ready to give up the notion of a physical brain that produces experiences. Kastrup’s idealist model, which explains the correlation as “experience produces the physical brain,” seems like a logically consistent and appealing alternative to dualism. But even if idealism is in fact true, the brain remains a useful metaphor to understand what's going on in the operations of the conscious mind.