Zombies
This chapter is about p-zombies and lying zombies: whether they are behaviorally and physically identical to human beings or not.
10.1. p–Zombies
A p-zombie (philosophical zombie) is generally defined as “a being that is physically identical to a normal human except that it lacks qualia and consciousness (conscious awareness and experience)” [1-15]. However, although this definition is philosophically possible, it is not certain that it is also physically tenable. This is because, if qualia and consciousness have physical effects, there might be something else that is physically associated with them disappears or changes in the p-zombie too when it lacks qualia and consciousness, and this will make the clause “physically identical to a normal human except that it lacks qualia and consciousness” impossible to be true physically. This problem will become obvious if we consider this definition in the form of equations:
A human = a being with qualia and consciousness and their effects … (1)
A p–zombie (philosophical definition) = A human – qualia – consciousness
= a being without qualia and consciousness but with their effects … (2)
Thus, if qualia’s and consciousness’s effects exist, Equation (2) will define a being that is impossible to exist physically because qualia’s and consciousness’s effects cannot occur without qualia and consciousness. And comparing a human with a possibly impossible physical entity will have no definite conclusion in the physical world. Therefore, if we want to do an experiment to see whether, physically, a being with qualia and consciousness and a being without them are behaviorally identical or not, we must use the definition that all the beings in the experiment can definitely exist physically. In doing so, we must take the possibility that qualia and consciousness may have physical effects into account. Thus, the appropriate definition must instead be a p-zombie is “a being that is physically identical to a normal human except that it lacks qualia and consciousness and their effects”, as in the following equation:
A p–zombie (physical definition) = A human – qualia – consciousness – their effects
= a being without qualia and consciousness and their effects … (3)
Whether qualia’s and conscious experiences’ effects exist or not is to be proved by separate investigations.
This is similar to the scenario that we define that a p-zombie is “a being that is physically identical to a normal human except that it lacks the pineal gland”. Again, although this definition is imaginarily possible, it is not physically possible. Because the pineal gland has a hormone and its physical effects, when the being lacks the pineal gland, it will lack the pineal gland’s hormone and its physical effects too, and this will make the clause “physically identical to a normal human except that it lacks the pineal gland” impossible to be true physically. The definition that is physically applicable has to be a p-zombie is “a being that is physically identical to a normal human except that it lacks the pineal gland and pineal gland’s effects”. These definitions can be summarized as the following equations:
A human
= a being with the pineal gland and pineal gland’s effects … (1)
A p–zombie (imaginary definition) = A human – pineal gland
= a being with pineal gland’s effects but without the pineal gland … (2)
(physically impossible, pineal gland’s effects cannot occur without the pineal gland)
A p–zombie (physical definition) = A human – pineal gland – pineal gland’s effects
= a being without the pineal gland and pineal gland’s effects … (3)
(physically possible)
From the definitions, a human (1) and a p-zombie (imaginary definition) (2) are different in only that the human has the pineal gland while the p-zombie does not. Everything else, including the pineal gland’s hormone and its effects (on behavior, other biological activities, and other things) in the p-zombie, who has no pineal gland, is the same. So, if we compare the two beings, we will find that they behave identically, and the conclusion will be that the world of p-zombies and the world of humans are behaviorally identical*. However, this conclusion is valid only imaginarily but not physically because a p-zombie as defined by the imaginary definition is physically impossible. Such a p-zombie cannot really exist, and neither can the world of such p-zombies. So, the conclusion that the world of p-zombies and the world of humans are behaviorally identical must be treated as an imaginary conclusion – this conclusion is not physically valid and is irrelevant to the real world.
(* Although this cannot be true in the present world due to advanced medical technology [such as MRI, CT scan, brain autopsy, or brain surgery] that can reveal the absence of the pineal gland and differentiate a p-zombie from a human, it could be true in the primitive world because, due to the lack of advanced medical technology, the lack of the pineal gland in the p-zombies would have been unnoticeable and thus virtually without physical consequences.)
On the other hand, from the definitions, a human (1) and a p-zombie (physical definition) (3) are different in that the human has the pineal gland and its effects while the p-zombie lacks both of them. Even if we grant that just the lack of the concealed tiny pineal gland in the head does not have any physical effects, the pineal gland’s hormonal effects have significant physical effects that cannot be assumed to be null, and the lack of them definitely has physical consequences. So, if we compare the two beings, we will find that they behave differently, and the conclusion will be that the world of p-zombies and that of humans are behaviorally different. This conclusion is physically valid and is relevant to the real world.
In the case of qualia and consciousness, the philosophical and the physical comparisons, like the comparisons in the case of the pineal gland, compare different pairs of entities and yield different conclusions. For qualia, the comparisons will be as follows.
A human
= a being with qualia and qualia’s effects … (1)
A p–zombie (philosophical definition) = A human – qualia
= a being without qualia but with qualia’s effects … (2)
(physically impossible if qualia’s effects do exist; they cannot occur without qualia)
A p–zombie (physical definition) = A human – qualia – qualia effects
= a being without qualia and qualia’s effects … (3)
(physically possible)
From the definitions, a human (1) and a p-zombie (philosophical definition) (2) are different in only that the human has qualia while the p-zombie does not. Everything else, including the qualia’s effects (on behavior, other biological activities, and other things) in the p-zombie, who does not have qualia, is the same. So, if we compare the two beings, we will find that they behave identically, and the conclusion will be that the world of p-zombies and the world of humans are behaviorally identical. However, although this is a philosophically valid conclusion, it is not certain that it is a physically valid conclusion. If qualia’s effects do exist, a p-zombie defined by this philosophical definition will be physically impossible to exist (because qualia’s effects without qualia are not physically possible). This conclusion, which may involve an impossible physical entity, thus may be physically invalid.
On the other hand, from the definitions, a human (1) and a p-zombie (physical definition) (3) are different in that the human has qualia and their effects while the p-zombie lacks both of them. If qualia’s physical effects exist, they will occur in the human, but not in the p-zombie; therefore, the p-zombie, who lacks qualia’s effects, will behave differently from the human, who has qualia’s effects. So, if we compare the two beings, we will find that they behave identically if qualia’s effects do not exist but will find that they behave differently if qualia’s effects do exist. So, whether the p-zombies behave differently from the humans and whether the world of p-zombies is behaviorally different from that of humans depend on whether qualia’s effects exist or not. This will be discussed later.
The comparisons are the same in the case of consciousness. Just replace qualia in the previous equations with consciousness.
At this point, it should be noted that one may believe and assert that qualia and consciousness do not have any physical effects, so they can be compared by using the philosophical definition, and the result will also be valid physically. However, using an inappropriate definition is not a correct way of doing a scientific experiment, even if it is a thought one, and can lead to confusion and misconception. Also, if one is committed to the belief that qualia and consciousness do not have any physical effects, then it is no use making the physical comparison between the human and the p-zombie – they are physically identical by the definition and the belief already. Because by the definition, the difference between the human and the p-zombie is qualia and consciousness, if qualia and consciousness do not have any physical effects, then the difference between the human and the p-zombie does not have any physical effects – that is, the difference between the human and the p-zombie is physically null, and the human and the p-zombie, with no physical difference, are physically identical. Stating in equations:
A human – a p-zombie = qualia and consciousness (by the definition) … (1)
Qualia and consciousness = no physical effects (by the belief) … (2)
A human – a p-zombie = no physical effects … from (1) & (2)
A human – a p-zombie = 0 (physically)
A human = a p-zombie (physically)
Thus, by the definition and the belief, a human and a p-zombie are already physically identical, and there is no use in doing thought experiments examining physical differences between physically identical entities. This is like comparing an ordinary computer with an n-computer, which is a computer with a name called by a human but not registered in the computer’s system. Because such names do not have any physical effects on computer functions, ordinary computers and n-computers will function identically, and the world of ordinary computers and that of n-computers will be physically identical. Undoubtedly, everyone knows that they are physically identical entities, and no one will spend time doing thought experiments examining physical differences between them. But do qualia not have physical effects on humans as names do not have physical effects on computers?
Actually, this problem has been discussed in detail in Chapter 5 and 6, and it has been proven that qualia and consciousness have physical effects (section 5.4. and 6.4.). This is simply because both qualia and consciousness have effects on the consciousness neural process: they induce the consciousness neural process to function to create conscious awareness and conscious experiences of themselves (this is evident by the fact that we do have conscious awareness and conscious experiences of both the qualia and our consciousness). Because the consciousness neural process is a physical process and because its function is affected, these effects are physical effects. And they are the physical effects that are to occur, at least.
Qualia → creation of conscious awareness and experiences of the qualia
Consciousness → creation of conscious awareness and experience of itself
Thus, qualia and consciousness to humans are not like names to computers, and the above belief (that qualia and consciousness do not have any physical effects) is not correct. Therefore, the philosophical definition is not physically tenable, and the result of thought experiments using philosophical definition is not physically valid.
In conclusion, we have to be careful how we define entities. If we define them philosophically or imaginarily, although such defined beings can exist in those realms, in some cases, such as the p-zombie cases above, they cannot exist in the physical realm, which is the real-life world. And the experiment conclusions pertaining to those definitions in such cases will be valid only imaginarily. Such conclusions are irrelevant to the real-life world. But if we define them physically, all the entities will exist in the physical realm, which is the real-life world. And the experiment conclusions pertaining to the physical definition will be valid physically. Such conclusions are relevant to the real-life world.
Now, let’s compare a human with a p-zombie (physical definition) to see their differences. Consider what happens in a human and a p-zombie when they see a tiger (Figure 10.1).
Figure 10.1 Human’s perception vs. p-Zombie’s perception
The early neural events in their visual pathways from the eyes to the cortical areas just prior to the cortical areas for perception are exactly the same. But once perception areas begin to function, further events are different. In the p-zombie, there will be a visual perception of the tiger, but this occurs without a quale and conscious experience, like an image registration in the motherboard of a present-day computer. In the human, in addition to the perception like the one that happens in the p-zombie, a visual quale of a tiger and a conscious experience of the quale occur in his mind. Because both the visual quale and the conscious experience of the quale cannot occur alone by themselves but must occur with some neural processes (Theorem I and Theorem III), some neural processes that do not occur in the p-zombie must occur in the human. They may cause more intense fear, more alertness, more sympathetic stimulation, etc., and additional or different behaviors will occur in the human. Thus, the human is physically and behaviorally different from the p-zombie. The world of p-zombies is, therefore, physically and behaviorally different from that of humans. And it can be concluded generally that a world with no qualia and consciousness is physically and behaviorally different from a world with qualia and consciousness.
This can be more obvious if we consider this matter in the opposite way. A present-day computer does certainly not have conscious awareness and experience of any quale that may occur in their circuits because there are no circuits built to do these specific functions (i.e., there are no circuits to be consciously aware of and to consciously experience any quale that may occur). Conscious awareness and experience of a quale are additional phenomena with additional information, and a computer needs additional circuits to manage these additional phenomena and additional information. A present-day computer thus needs additional circuits to do these functions. Therefore, all functions else being the same, a computer that can function to have conscious awareness and experiences of qualia must have additional circuits and will thus be physically and functionally different from computers that cannot function to have conscious awareness and experiences of qualia.
10.2. Lying zombies
A lying zombie or a confabulating zombie is a hypothetical being that is physically identical to a normal human except that it lacks qualia and consciousness (conscious awareness and experience), yet it lies** that it has both phenomena, and it can talk about them in detail and can do everything else (such as experiments) relating to them like us. Also, the world of lying zombies will have philosopher zombies that are interested in the phenomena of qualia and consciousness, even if these phenomena never occur in them. They can discuss these phenomena seriously and comprehensively as we do as if they had experiences of these phenomena, even if they never have experiences of these phenomena. Moreover, the world of lying zombies will have neuroscientist zombies that are interested in these phenomena too. They will carry on a lot of experiments to test these phenomena and try to form theories explaining these phenomena – even if these phenomena never occur in them. The world of these zombies is thus identical to the world of human beings.
(** To lie here simply means to say untruthfully. It does not imply pretending or insincere intention.)
But is it possible that such lying zombies exist? Can zombies that do not have qualia and consciousness talk about, discuss, and do experiments on these phenomena seriously as we do? The following arguments are against the existence of such lying zombies:
- If lying zombies do not have qualia of and conscious awareness and experiences of vision, sound, emotion, etc. but lie that they do, then why do they not lie that they have qualia of and conscious awareness and experiences of blood levels of oxygen, sodium, hormones, etc. of which they do not have qualia and conscious awareness and experiences either? Why do they lie that they have qualia of and conscious awareness and experiences of only the kinds of qualia and conscious awareness and experiences that we have?
- Why do lying zombies not lie about other things too; why do they select to lie only having qualia and consciousness? If lying zombies do not have qualia and consciousness but lie that they do, then why do they not lie that they have other mental phenomena that they do not really have either? For example, they could lie that they also have mental phenomena called qualax, qualor, or other phenomena that are indescribable to us, who do not have these mental phenomena. Why do they specifically lie only that they have qualia and consciousness, which are the very phenomena that we have?
- The most important reason is: how can a lying zombie think and talk about something that never happens to it and that it does not have information about? How can a world of lying zombies start discussing things that never occur to them and continue to discuss those things seriously? If something never happens to zombies, they cannot have information about that thing and cannot start talking about that thing or do anything about that thing at all, not to mention continue discussing it seriously or carry on experiments about them continuously like us. This is also true for us: we cannot start talking about, continue discussing, or carry on experiments about qualax, qualor, or other phenomena that we do not have information about.
Let’s analyze this problem physically. Consider a being A, which is a lying zombie. When a vision and a sound enter its brain’s neural processes, because qualia and conscious experiences do not occur, what happens in the zombie is only the perception of the vision and the sound. It certainly can tell that they are different information. But if it is asked what it feels like to see or hear those sensations, it will not be able to understand what the question means because “what it feels like to see or hear” does not happen in it. It thus does not have information about “what it feels like to see or hear” to process (to think about, to talk about, to discuss, etc.) and will naturally ask what we mean by that question.
Now, consider a being B, which is a normal human. When a vision and a sound enter its brain’s neural processes, qualia and conscious experiences occur, and the human will have the conscious awareness and experiences of the qualia’s occurrence and of what the qualia are like occurring. These are additional phenomena with additional information that occurs in the human’s brain but not in the zombie’s. When the human is asked what it feels like to see or hear those sensations, although he may not be able to answer it clearly, he will understand what the question means because “what it feels like to see or hear” happens in him/her and because he/she has information about them to process (to think about, to talk about, to discuss, etc.).
In conclusion, perceptions without qualia and consciousness have different information from perceptions with these mental phenomena. A being with the former perceptions will not have the additional information of the latter perceptions and will not be able to think about, talk about, or do anything about these additional mental phenomena. Therefore, lying zombies are impossible, and the world of lying zombies is not possible either.
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