Extra Chapter III

P-zombie

In our daily lives, we talk, work, play, and engage in various other activities with other people all the time. Most of us probably do not think about whether they experience the world as we do because they behave very similarly to us. Therefore, it seems reasonable to assume that they are like us internally. Still, some people suspect that that is not the case. They conceive that, while we see things around us, listen to songs, smell flowers, and enjoy their lively images, beautiful sounds, or sweet smells, other people may not have these vibrant phenomena occurring in their minds when they experience the same things. That is, while we are living in a world of dazzling phenomena, other people may be living in a dark, phenomenon-less world. The question is whether this surmise is valid.

These vibrant phenomena we experience in our minds are called qualia, and the awareness and experiences of what they are like (such as awareness and experiences of what colorful images, melodic sounds, or sweet smells are like) are called conscious awareness and experiences, or consciousness. This chapter examines whether there can be beings without qualia and consciousness but can live and behave exactly like us or be physically identical to us, who have qualia and consciousness, and whether there are such beings living among us or some people around us are such beings. 

III.1 Philosophical Zombie

In philosophy, such a being is called a philosophical zombie or a p-zombie, which is defined as “a being that is physically identical to a human but lacks qualia and consciousness” [1–23]. This concept likely originated from some people’s notion that qualia and consciousness do not have physical effects; therefore, lacking them would not result in physical differences. In real life, when we observe people going about their activities, we can truly doubt the role of qualia and consciousness. It is not apparent that they assist us in our activities, so it is not illogical to believe we can continue doing everything normally without them. This idea gains further support in the present world when we witness computers, robots, and various automated machines efficiently performing diverse tasks despite lacking qualia and consciousness. Accordingly, qualia and consciousness may be unnecessary, and some argue that we can live and function as usual without them.

However, for the above definition to be valid, qualia and consciousness must not have physical effects. Otherwise, the definition defines some being lacking something with physical effects as physically identical to another being having that something, which is not possible. Also, if qualia and consciousness have physical effects, the definition defines a certain being lacking qualia and consciousness as having their effects, which is also impossible. This discrepancy in the definition occurs because the definition defines a being as lacking only qualia and consciousness but otherwise physically identical to a human, meaning the defined entity still possesses qualia and consciousness effects as the human does. Overall, if qualia and consciousness have physical effects, the definition defines a physically impossible being. This problem becomes more evident when we consider it in the form of equations and a picture, as follows:

(In the following discussions and picture, Q & C = qualia and consciousness, QCE = qualia’s and consciousness’s physical effects, MA = mental activities, “+” = “with,” and “–” = “minus”)

A human = a being + Q & C + QCE + other MAs … (1)

A p–zombie = a human – Q & C … (2) (by definition)

= a being + QCE + other MAs … (3) … [from (1) and (2)]

The definition defines a p-zombie as physically identical to a human. 

A p–zombie ≡ A human … (4)

a being + QCE + other MAs ≡ a being + Q & C + QCE + other MAs … (4′)

p-zombie

Figure III.1 P-zombie: physically identical to a human but lacking Q & C

It is obvious that if Q & C do not have physical effects, both Q & C and QCE will be physically null (= 0). Hence, (3) will define a physically possible entity, and (4) and (4′) will be true. Accordingly, a p-zombie will be a physically possible entity and thus can exist physically. On the contrary, if Q & C have physical effects, both Q & C and QCE will not be physically null. Accordingly, (3) will define a physically impossible entity (a being with QCE but lacking Q & C is physically impossible), and (4) and (4′) will be physically invalid (defining a physically impossible entity, as just discussed, to be physically identical to a real physical entity, a human, is physically invalid). Therefore, a crucial question is whether Q & C have physical effects or not.

The answer is affirmative. This matter has been analyzed in detail in Chapters 5 and 7, and it has been demonstrated that Q & C have physical effects. They have physical effects simply because they induce the brain to create awareness and experiences of themselves. Evidently, we are aware of and experience their occurrences and what they are like:

Qualia → awareness and experiences of their occurrences and of what they are like.

Consciousness → awareness and experiences of its occurrence and of what it is like.

Because all awareness and experiences require specific neural processes to function for their occurrences—they cannot occur alone (Theorem I)—qualia and consciousness must induce functions of certain neural processes. As neural process functions are physical, qualia and consciousness induce certain physical functions. Thus, they have physical effects, and these effects are their earliest physical effects. Other physical effects subsequently follow and are numerous. For example, we think about, talk about, have conferences on, conduct research on, and write articles and books about them; even the reader is reading an article about them right now. None of these physical activities would occur if qualia and consciousness had no physical effects.

Therefore, because qualia and consciousness have physical effects, both Q & C and QCE are not physically null. This has two critical consequences:

     1. A being lacking Q & C cannot be physically identical to a being with Q & C. Yet a p-zombie is defined as lacking Q & C but identical to a human (a being with Q & C), which is not physically possible. Thus, a being defined by this definition is not a physically possible entity.

     2. Also, since a p-zombie is defined as lacking Q & C but otherwise identical to a human, which is a being with QCE, it must also have QCE like a human. However, having QCE without Q & C is physically impossible. In this aspect, the definition also defines a physically impossible entity.

Summarily, a p-zombie defined by this definition is an impossible physical entity and, although it can exist imaginarily, cannot exist physically. There cannot be such p-zombies among us, nor can some of us be p-zombies. Likewise, the conjecture that, while we live in a world of dazzling phenomena, some other people live in a dark, phenomenon-less world yet can behave like us is false.

III.2 Physical Zombie

Let us define a new p-zombie, a physical zombie, as a human who lacks only qualia, consciousness, and their physical effects. Theoretically, this can be caused by a disease or condition that selectively affects the neural processes involved in the qualia and consciousness generation without affecting other brain parts, such as a limited cerebral infarction in the areas of these neural processes. 

Obviously, from this definition, this p-zombie cannot be physically identical to a human because it is a being lacking some physical things a human has. However, everything else (which is not qualia, consciousness, or their effects) in the p-zombie is the same as that in a human. Because the definition does not require a p-zombie to be physically identical to a human, there is no contradiction in the definition. Therefore, a p-zombie defined by this definition is a possible entity and can physically exist. Indeed, there exists a real physical zombie in the medical literature. A patient with a stroke lost conscious color perception but still had unconscious color perception: He was able to describe the colors of objects correctly above chance to some degree, even though he denied perceiving those colors and did not have the color qualia [24].

Now, let us study what happens in a p-zombie and a human when they see a tiger (Figure III.2). 

p-zombie

UP = unconscious perception, Q = image quale of the tiger
CA = conscious awareness of Q, CE = conscious experience of Q
Figure III.2 P-zombie’s perception vs. human’s perception

The early neural events in the visual pathways from the eyes to the cortical areas immediately before the cortical areas for visual perception are the same. However, after the perception areas begin to function, the events differ. In the p-zombie, there is an unconscious visual perception of the tiger (1. UP), but this occurs without a quale, conscious awareness, or a conscious experience, similar to image registration and other related electronic operations of an image on the motherboard of a present-day computer. In the human, in addition to unconscious perception (1. UP), similar to that in p-zombie, a visual quale of the tiger (2. Q) occurs. After this, conscious awareness and experience (3. CA + CE) of the quale occur. Subsequently, conscious awareness and experience of the conscious awareness and conscious experience of the quale also occur. Conscious awareness and conscious experiences, like other mental processes, require specific neural processes for them to occur; they cannot occur alone by themselves (Theorem I). Therefore, additional neural processes that do not occur in the p-zombie occur in the human. These additional neural processes, being physical, must have physical effects that do not occur in the p-zombie. However, although we know some of their physical effects, as just discussed above, we still do not know precisely what other effects are. They may cause more intense fear, alertness, and sympathetic stimulation. However, their final behavioral effects are obvious and numerous, as mentioned near the end of Section III.1. Thus, it is definite that the human is physically and behaviorally different from the p-zombie. Hence, the human world is physically and behaviorally different from that of p-zombies. Moreover, it can be concluded generally that a world without qualia or consciousness is physically and behaviorally different from a world with them.

This matter can be more obvious if we consider it in the opposite way. A present-day computer certainly does not have conscious awareness or experiences of any quale that may occur in it. This is because conscious awareness and a conscious experience of a quale are additional functions with additional information, which need additional circuits, software, or both to operate the new functions and manage the added information. However, at present, there are neither circuits nor software in the computer to operate these novel functions and manage the extra information because we, their creators, do not build such circuits and software for it as we, at present, simply do not know how to do so. Therefore, a computer that can function to have conscious awareness and conscious experiences of qualia must have additional circuits, software, or both. Thus, it will be physically and functionally different from computers that perform other functions similarly but cannot function to have conscious awareness and conscious experiences of qualia. (More detailed discussions of this matter are provided in Chapter 9, Section 9.3.1: Do computers and robots have qualia and consciousness?)

III.3 Remarks

In conclusion, since qualia and consciousness have physical effects, philosophical and physical zombies, defined as lacking qualia and consciousness, cannot be physically identical to humans, who possess both. However, philosophical zombies are also defined as being physically identical to humans, which is impossible, and as having the effects of qualia and consciousness, which is also impossible. Hence, they are physically impossible entities and cannot exist physically. On the other hand, physical zombies are not defined as being physically identical to humans or as possessing qualia’s and consciousness’s effects. They are thus physically possible entities and can exist physically.

⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓ ⁓

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