Extra Chapter II

Variable Qualia

When one looks at a house, listens to a song, or smells a flower, an image quale of the house, a sound quale of the song, or an odor quale of the flower appears in one’s mind. Because these qualia seem unique and fascinating, some people wonder whether others experience them similarly to or differently from how they do. For example, please see Figure II.1. When people look at the same color C, is it the case that the color C qualia appear as red in some people but as blue, green, or other colors in others? Moreover, is it possible that, in some people, the color C qualia appear as some extraordinary colors that are not in the normal color spectrum that general people perceive (so the colors cannot be shown here, or even in any other pictures), such as the color represented by “!” in the figure?

Figure II.1 Variable color qualia among people

Despite these strange possibilities, all people will call what they see in their minds the same, “color C,” even though the manifestations of the color qualia in their minds are different (red, blue, green, etc.). Even more bizarre possibilities are that the color C qualia may appear in some people as other kinds of qualia, such as the auditory quale, olfactory quale, or the quale of an unusual percept that occurs only in some people instead of the color quale. Remarkably, despite these differences, all of them will still call what they experience in their minds the same: Color C.

Although philosophers have long presented and discussed this puzzle [1–3], it remains unresolved. Therefore, this chapter attempts to find solutions based on scientific evidence. It finds that there are several variations of this puzzle and that some of them have definite answers.

Variable Qualia

In this theory, qualia that manifest themselves variably, that is, manifest themselves differently in the minds of different people even though they are qualia of the same thing, are called variable qualia. Hypothetically, there can be various types of variable qualia, not just the type in the example above. Based on the causes of variability (physical vs. non-physical) and how variability occurs (randomly vs. restrictedly and completely vs. partially), they can be classified as follows:

II.1 Physically originated variable qualia
II.2 Non-physically originated variable qualia
II.2.1 Randomly variable qualia (RVQ)
• II.2.1.1 Randomly variable qualia-complete (RVQc)
• II.2.1.2 Randomly variable qualia-partial (RVQp)
II.2.2 Restrictedly variable qualia
• II.2.2.1 Inverted qualia
• II.2.2.2 Shifted qualia
• II.2.2.3 Identical-structure qualia

Now, let us investigate them to see which ones can occur and which ones cannot.

II.1 Physically Originated Variable Qualia

Physically originated variable qualia are qualia that are variable and appear differently among people because of physical causes. 

Variability in qualia of this kind occurs because many physical factors that are involved in the processes of perception and affect the perception of neural processes, associated mental processes, and associated qualia, such as environmental, anatomical, and physiological factors, are different among individuals. For example, in the case of perceiving a color, the environmental factors, such as the illuminating light, the light’s angle of incidence, the light’s angle of reflection, and the intervening medium (e.g., air, water, and glass) between the color and the observer’s eyes, and the anatomy and physiology of the whole visual perception pathway, from the corneas of the eyes to the neural circuits for visual perception, differ among people. Consequently, the resulting neural processes’ and mental processes’ perception and the associated perception qualia (which, according to Theorem IV, are the signaling patterns of the associated neural processes) will be different. Thus, it is highly likely that different people will consciously experience (mentally see) the same color differently, but only slightly if their brains are normal and all physical factors are not significantly different. 

The differences between physically originated variable qualia of the same object among normal people are usually small because the differences in the resulting neural processes and signaling patterns, which are qualia, are only slight. Drastic differences in physically originated variable qualia of the same thing under similar perceiving conditions in healthy people usually do not occur. This is evidenced by the fact that general people do not feel that their perception of things is very different and do not argue about it. The differences that occur are readily accepted because they are usually caused by known physical factors, such as short- or long-sightedness, low- or high-frequency hearing loss, and different thicknesses of the palm skin (which affect cutaneous sensations).

However, significant differences can occur in physically originated variable qualia if the perception systems have abnormalities or if the perceiving conditions are different. For example, color blindness can cause visual color qualia to be very different from those in normal people; gustatory (taste) qualia of the same food can be very different among people if the food they consumed immediately before had very different tastes; also, various diseases or conditions that affect sensory perception systems can cause qualia that are very different from normal, such as abnormal skin sensation perception (e.g., numbness, hyperesthesia, and paresthesia), abnormal odor perception (e.g., hyposmia, hyperosmia, and parosmia), and abnormal sound perception (e.g., hyperacusis, presbycusis, and diplacusis). Moreover, qualia that are very different from normal can result from illusions, hallucinations, and an interesting syndrome called synesthesia.

Synesthesia

Synesthesia is a condition in which a stimulus in one sensory modality, in addition to triggering the primary percept in that modality, automatically and consistently triggers a secondary, concurrent percept in another modality [4–21] or in another type of the same modality. For example, color perception occurs in addition to sound perception when people with music-color synesthesia hear musical sounds or in addition to letter or number visual perception when people with grapheme-color synesthesia see letters or numbers. Many scientists believe that synesthesia occurs because there are unusual neural connections between perception neural circuits of different modalities such that, when a perception neural circuit of one modality (such as auditory) is stimulated to function by a stimulus, another perception neural circuit of a different modality (such as visual) will function simultaneously, such as in people with music-color synesthesia. In other types of synesthesia, unusual neural mechanisms activate perception neural circuits of different types but of the same modality, such as the visual perception neural circuit of form and that of color in people with grapheme-color synesthesia [21]. Other possible underlying mechanisms for synesthesia generation include disinhibited feedback, hyperconnectivity, hyperbinding, and enhanced white matter connectivity [19]. However, some studies have shown that synesthetic experiences (e.g., synesthetic perception of colors) are not equivalent to real perception (e.g., color perception that occurs from actually seeing colors) [22] and that the cause of synesthesia may be something else, such as a special kind of childhood memory that is recalled when there is some sensory perception occurring [23] or distributed processing of synesthetic associations [22]. However, despite uncertainty regarding the exact mechanisms that create synesthesia, it can be concluded that they are physical mechanisms involving neural connections, functions, or both. 

Qualia that occur in people with synesthesia thus differ from those in general people who experience the same thing because there are two types of qualia co-occurring. Because these extra qualia occur because of physical mechanisms, qualia in these people vary from qualia in general people because of physical causes and thus are physically originated variable qualia.

II.2 Non-Physically Originated Variable Qualia

Non-physically originated variable qualia are qualia that are variable and appear differently among people by themselves, not because of physical causes. They can be classified as listed at the beginning of this chapter. One example of this type of variable qualia is the frequently-talked-about color qualia that can appear red in some people but blue in others (so that “your red is my blue,” as some people suspect). However, theoretically, several other types can manifest themselves variably in other ways, and some of them are interesting and illuminating. Hence, we will examine them in detail as follows:

II.2.1 Randomly variable qualia (RVQ)

Randomly variable qualia (RVQ) are qualia that are randomly variable and appear differently in a random manner among people. They can be subclassified into two groups depending on whether the randomness is complete or partial, as in Table II.1.

II.2.1.1 Randomly variable qualia-complete (RVQc)

Randomly variable qualia-complete (RVQc) are qualia that are randomly variable and appear differently in a completely random manner among people. RVQc of something will appear differently in every instance. For example, if color C qualia are RVQc, they will appear as red, blue, green, and other colors randomly at different points in the reader’s visual field (VF)—they will not appear as the same colors at all the VF points. Moreover, they will also do so in the author and other people. (Please see Row 1. RVQc in Table II.1.) Thus, the randomness is complete because the variability occurs in all cases, both in a single individual and in different individuals. 

Table II.1 Manifestations of Randomly Variable Color C qualia

	Manifest in one individual as	Manifest in several individuals as
RVQc	red, blue, green, and other colors	red, blue, green, and other colors in every individual
RVQp	a certain color	a certain color in one individual but other certain colors in other individuals

II.2.1.2 Randomly variable qualia-partial (RVQp)

Randomly variable qualia-partial (RVQp) are qualia that are randomly variable and appear differently in a partially random manner among people. RVQp of something will appear differently only when they occur in two or more individuals but will not appear differently in any single individual. For example, if color C qualia are RVQp, they will always appear as a certain color in an individual, such as red in the reader, blue in the author, green in another person, yellow in yet another person, and so on. However, they will not appear as red, blue, green, yellow, and other colors (as RVQc do) in any single individual. (Please see Row 2. RVQp, Table II.1). (Please see Row 2. RVQp, Table II.1). Therefore, in any one individual, they are not variable and will not appear differently; only among two or more individuals will they be variable and appear differently. Thus, they are randomly different in a partial manner because they require two or more individuals to manifest their variability.

The question is whether RVQ occur in the real world. To answer this question, we will investigate them in more detail as follows:

II.2.1.1 Randomly variable qualia-complete (RVQc)

For RVQc, there is evidence that they do not occur in the real world. Consider the following example. 

A visual image that occurs in one’s mind is not an all-or-none phenomenon. Instead, the entire visual image comprises millions of independent tiny visual images joined seamlessly by the visual perception neural processes. Each tiny visual image is created by a tiny perception neural process of that point in the visual field. If there is damage to some of these tiny neural processes, it will affect only the tiny images at the corresponding points in the visual field, leaving those in the unaffected part intact. For example, a lesion in the right occipital cortex can result in a defect (scotoma) at the corresponding portion of the left visual field, leaving the rest of both visual fields undisturbed. In addition, because there are separate perception neural processes for each specific characteristic (i.e., color, shape, and movement) [24,25], various types of defects can occur separately and independently. For example, a right occipitotemporal infarction can result in achromatopsia (cerebral color blindness) in a part of the left visual field [26–29], while other visual components (i.e., shape and movement.) remain intact. Thus, the entire visual image in the mind comprises millions of independent tiny visual images, each composed of several independent types of visual characteristics.

Now, suppose one is looking at a screen of homogeneous color “C” (Figure II.2A). All the tiny neural processes for color perception must be creating the same signals—the color “C” signal—separately, and the quale for each tiny neural process must be occurring separately. If RVQc are possible, each quale of several million tiny neural processes that generate the whole image can manifest itself differently as red, blue, green, or other colors randomly, and the entire visual image may not be a homogeneous color but a mixture of myriad different-color bits (as in Figure II.2B). 

However, in reality, this does not happen. If any quale of tiny Color “C” neural processes in Figure II.3A manifests itself as red, all the others will also manifest themselves as red, and the screen will be pure red (as in Figure II.3B).

Similarly, a pair of same-color discs (such as red and red) is always perceived as a pair of same-color discs (such as red and red, as in Figure II.4A), not a pair of different-color discs (such as red and blue, as in Figure II.4B), which can occur if RVQc are possible because the color in one disc may appear as red, while in the other, as blue.

(* One may ask, “How do we know that the colors being compared are the same colors in the first place?” The answer is that we can know objectively, independently of our perception, whether the two or three or more colors that are being compared are the same colors by checking their radiation wavelengths with our instruments—for example, they will be found to have wavelengths of 700 nm if they are red.)

Therefore, for the same colors in the outside world, the same color qualia occur in millions of tiny neural processes, and RVQc do not occur. In addition, it never happens that color qualia occur at only some points in the visual field but that auditory, olfactory, or other kinds of qualia occur at other points in the visual field. This means qualia do not vary from visual to other types of qualia either. 

Similarly, evidence indicates that the RVQc do not occur in other kinds of sensory perception either. For example, when two identical musical instruments play the same musical note, “M” (M stands for a certain musical note), the quale of the sound from each instrument will have a chance to manifest itself differently if RVQc are possible; consequently, one may appear as the piano sound of note C, while the other, the violin sound of note G. This is, of course, absurd and never happens. Everyone will hear the two sounds as the same musical note of the same musical instrument, such as the flute sound of note A if it is the flutes playing note A. The same scenario is similar for other kinds of sensory perception, such as the feeling of the same touches on both arms, the pain from the needle stabbing with similar strength on both legs, and the taste of the same honey on both sides of the tongue—the qualia of the same things on both sides are always the same, not randomly different, in any single individual.

Thus, there is no randomness in the manifestation of qualia of the same thing in any single individual. This “no randomness in manifestation in a single individual” of qualia has been consistently true for a long time in billions of humans everywhere nowadays and in the past—no normal person has ever reported having variable qualia occurring when perceiving a homogenous stimulus or identical stimuli. Thus, although RVQc has virtually infinite chances to manifest themselves, they have never done so. Accordingly, it can be concluded that RVQc do not occur. 

It is essential to note that the non-occurrence of RVQc is evidence that qualia are physical phenomena, governed by some physical laws. If qualia are non-physical phenomena, not governed by any physical laws, there would be nothing to control their manifestations. Consequently, they would be able to appear differently in a completely random manner in all individuals, and all the strange phenomena in the discussions above would occur.

II.2.1.2 Randomly variable qualia-partial (RVQp)

However, is it possible that qualia do not appear differently in a single individual because there is only one individual’s consciousness to experience the qualia? Is it the case that qualia will appear differently if there are several individuals, and thus different consciousness, to experience the qualia? As discussed before, this possible type of variable qualia is called randomly variable qualia-partial (RVQp) because it requires the presence of several individuals. Now, is there evidence that RVQp occur? The answer is that there is evidence that RVQp do not occur either.

Let us consider the case of color qualia in Figure II.5. Quale 1 and quale 2 are color qualia of two different colors (the color difference can be objectively verified by measuring their light wavelengths with some instrument).

Figure II.5 Qualia 1 and 2 manifest as different color pairs in three people

If RVQp occur, then quale 1 can randomly manifest itself in person 1 as red, person 2 as blue, and person 3 as yellow, while quale 2 can do so in person 1 as blue, person 2 as teal, and person 3 as orange-yellow. Now, please consider the upper row. This is the case of “your red is my blue” for person 2 vs. person 1 and “your red is my yellow” for person 3 vs. person 1. Next, please examine both rows for each person. Person 1 will say that qualia 1 and 2 are markedly different in hues and warmth, with quale 1 being much warmer than quale 2. Certainly, persons 2 and 3 will not agree with these remarks. Person 2 will say that the two qualia are not markedly different in their hues and warmth, and quale 1 is not warmer than quale 2, whereas person 3 will say that the two qualia are only minimally different in hues and warmth.

However, such disagreements do not occur among people with normal vision. When some people with normal vision observe a pair of certain colors to be markedly different in hues and warmth, with the first color being much warmer than the second, such as the pair of red and blue that person 1 sees, other people with normal vision will agree with these observations. This means that they (such as persons 2 and 3) see similar color pairs and not different color pairs, as shown in Figure II.5. Thus, it can be concluded that qualia 1 and 2 do not manifest themselves randomly differently in people so that different color-pairs appear in different people. This provides evidence that RVQp do not occur. 

Another piece of evidence is a wheel of discs with gradually changing hues like the one in Figure II.6A. Anyone with normal color vision will agree that the hues of colors in such a wheel gradually change from one disc to another successive disc.

Figure II.6A                                    Figure II.6B

However, if RVQp occur, the color quale of each disc in the wheel will manifest itself haphazardly. For example, in some people, the red at 12 o’clock in II.6A will manifest as orange in II.6B; the yellow at 4 o’clock in II.6A, red in II.6B; and the blue at 8 o’clock in II.6A, light green in II.6B. This will result in a color wheel that has the hues of successive discs change not gradually but haphazardly, like the color wheel in Figure II.6B, in some people. But this never happens in billions of people with normal color vision. They always agree that the hues of the colors in a color wheel, like the one in Figure II.6A, gradually change from one successive disc to another. Thus, RVQp do not occur in this case either. 

The evidence in auditory perception is that, if RVQp occur, the pitch qualia of musical notes must be randomly different among people. For example, some may perceive the pitch quale of a certain musical note M as the note C, some as the note F, and some as the note A^#; and for the next sound that is one semitone higher, or note M^#, some people may perceive it as C^#, some as C^b, and others as G. These differences will make people perceive the pitch intervals between the same two notes (M and M^#) differently. However, such dissimilar experiences do not occur in real life. Likewise, if RVQp occur, a musical scale must sound differently among people, with each note on the scale perceived differently. Consequently, a train of musical notes that have pitch qualia as C-D-E-C-E-C-E (i.e., do-re-mi-do-mi-do-mi) in some people may have pitch qualia as F-C-B-F-B-F-B (i.e., fa-do-ti-fa-ti-fa-ti) in some people and as something else in others. A train of musical notes will appear as music in some people but as chaotic sounds in others. These strange phenomena never happen, however. People agree on the orderly sounds of musical scales and music and the chaotic sounds of noise. Similarly, there are no RVQp occurrences in other kinds of sensory perception either. For example, all people perceive a series of smoothly increasing vibration or sweetness stimuli as smoothly increasing strength stimuli. It is not that some individuals perceive it as haphazardly changing strength stimuli, which can occur in some individuals if RVQp are possible.

Therefore, there is no randomness in the manifestation of qualia among individuals. This “no randomness in manifestation” of qualia has been consistently true for a long time in billions of people everywhere nowadays and in the past. Thus, although RVQp have virtually infinite chances of manifesting themselves, they never do so. Hence, it can be concluded that RVQp do not occur in the real world. Regarding the interesting hypothetical phenomenon of “your red is my blue,” although at first it seems very probable that this phenomenon can occur from variable qualia of this type—RVQp—which is a type that can manifest themselves randomly differently among different people, it has now been shown that that is not the case. RVQp do not occur and is thus not the cause of the “your red is my blue.” Therefore, if this interesting phenomenon occurs, it must arise from the variable qualia of other types, or it might not occur at all. This will be discussed in the following sections.

II.2.2 Restrictedly variable qualia

Restrictedly variable qualia are qualia that are restrictedly variable and appear differently in restricted ways among people.

Although there is no evidence that qualia manifest differently among people randomly, as discussed in the previous section, is it possible that they can manifest differently among people in restricted ways? For these restricted types of variable qualia, some rules restrict how they appear differently among people. For example, the rules may be that the reader’s pitch qualia are one semitone higher than the author’s but that other characteristics of our sound qualia are the same. Such rules will result in the reader and author having similar acoustic experiences of all musical notes, chords, music, and so on. As a result, we will never be able to tell that we are experiencing different qualia. The reason why we cannot distinguish them will be discussed in detail in Section II.2.2.3. For now, this demonstrates a simple example of restrictedly variable qualia. Theoretically, there are several types of restrictedly variable qualia. Let us study some interesting types to see if they can occur among people without people knowing that they are experiencing variable qualia.

II.2.2.1 Inverted qualia

Inverted qualia are hypothetical qualia that have their manifestations, such as colors or sound pitches, inverted [1,3,30–32]. Theoretically, they exist in several forms. In the most frequently discussed form, inverted qualia exist with their non-inverted counterparts, and qualia in each group can form a spectrum with their manifestation parameters (such as the corresponding light or sound wavelengths of color or pitch qualia, respectively) arranged ordinally. If the arrangement is regularly increasing or decreasing in the parameter values, the spectrum resembles the light spectrum in the case of color qualia and resembles the chromatic scale in equal temperament in the case of pitch qualia. The inverted spectrum is equivalent to the spectrum resulting from inverting the non-inverted spectrum. If the two spectra are placed side by side with their ends aligned, each quale at every point on the inverted spectrum is the inverted quale for the quale at that same point on the non-inverted spectrum. For example, in Figure II.7, Spectrum A is the normal color-qualia spectrum, its color qualia ordinally arranged based on their corresponding light wavelengths, and Spectrum B is the inverted color-qualia spectrum, obtained from inverting Spectrum A with respect to the wavelength.

Figure II.7 A: a normal color-qualia spectrum, B: an inverted color qualia spectrum

It can be seen that dark red, yellow, and blue in Spectrum B (marked by red stars in the figure), for instance, are inverted colors for indigo, green, and red in Spectrum A. Now, when people with normal color vision see the light spectrum, they will see it as Spectrum A. For them, they will see distinct changes in hues around wavelengths of 410, 470, 490, 570, and 610 nm. However, if color qualia appear in some people as inverted color qualia, the light spectrum will appear to those people as Spectrum B instead. Evidently, they would not agree with the previous observations. For them, distinct changes in hues are observed at wavelengths of 510, 550, 630, 650, and 710 nm. However, people with normal color vision do not disagree about the wavelengths at which the light spectrum changes hues. The lack of disagreement among people is evidence that inverted color qualia of this kind do not occur in humans.

Next, let us consider inverted pitch qualia, pitch qualia of a chromatic scale in equal temperament (Scale 1), in which C’ is one octave higher than C, and its inverted counterpart (Scale 2), in which the order of all the notes is reversed, are represented as rows of musical alphabets below.

Scale 1: C C^# D D^# E F F^# G G^# A A^# B C’

Scale 2: C’ B A^# A G^# G F^# F E D^# D C^# C

If inverted pitch qualia occur in some people, they will hear the notes in Scale 1 as those in Scale 2. For example, while people experiencing normal pitch qualia hear the 1st, 5th, and 8th notes as C, E, and G, people experiencing inverted pitch qualia will hear them as notes C’, G^#, and F. Although, we cannot tell that people in both groups are experiencing different pitch qualia when they hear these individual notes because there is nothing to use as a reference for comparison, we can differentiate the two groups when they hear musical chords. This distinction is possible because the two scales have similar chords constructed from equivalent notes on each scale sound different. For example, the chord constructed from the 1st, 5th, and 8th notes (C-E-G) on Scale 1 sounds C Major, which is bright and cheerful; on the other hand, the chord constructed from the 1st, 5th, and 8th notes (C’-G^#-F) on Scale 2 sounds F Minor, which is subdued and cheerless. This kind of difference is also the case for other chords. Consequently, similar chords constructed from the inverted scale sound different and have different aesthetic (e.g., emotional) effects from those constructed from the normal scale. If this kind of inverted pitch qualia occurs in some people, they will disagree with people who experienced the normal pitch qualia about the mood of a particular chord. However, this kind of disagreement does not occur in the real world—the same chords sound similar and have similar aesthetic effects among all people with normal hearing. This is evidenced by the fact that they do not dispute this matter. Therefore, it can be concluded that such inverted pitch qualia do not occur in individuals.

Other types of inverted qualia are possible with color qualia. In one interesting type, each inverted color quale and its corresponding normal color quale form a pair of inverted colors, which are two colors with complementary RGB (Red, Green, Blue) values that add up to 255 (the maximal RGB value). Now, when people experiencing normal color qualia see the light spectrum, they will see it as Spectrum A in Figure II.8. However, people experiencing inverted color qualia of this form will see the light spectrum as Spectrum B, any color of which is an inverted color of the color at the same wavelength on Spectrum A.

Figure II.8 The light spectrum as seen in the normal (A) and inverted (B) forms

Because the light spectrum appears to these two people groups as different spectra, they disagree on various spectral characteristics, such as, like the previous discussions for Figure II.7, where hues change markedly along their spectra. Additional examples of possible observation differences are i) from wavelengths 580 to 640 nm, people experiencing normal color qualia see greenish yellow changes to red, a markedly different hue, while people experiencing inverted color qualia see dark blue changes to light blue, a slightly different hue, and ii) from wavelengths 510 to 590 nm, people in the first group see green changes to yellow, a fairly close hue, but people in the second group see red-pink changes to dark blue, a markedly different hue. Therefore, if inverted color qualia of this type occur among people, they will be able to tell from their different observations that they are experiencing different color spectra of the same light spectrum. However, this kind of disagreement does not happen. This is evidence that inverted color qualia of this type do not occur in humans.

II.2.2.2 Shifted qualia

Shifted qualia are theoretical qualia with manifestations, such as colors or pitches, shifted up or down along their spectra relative to the non-shifted qualia. Like the first form of inverted qualia discussed above, non-shifted and shifted qualia can form spectra with their manifestation parameters (such as the corresponding light or sound frequencies) arranged ordinally. For non-shifted qualia, the spectrum resembles the light spectrum in the case of color qualia and resembles the chromatic scale in equal temperament in the case of pitch qualia. The shifted spectrum is equivalent to the spectrum resulting from shifting the non-shifted spectrum up or down along its spectrum. If the non-shifted and shifted spectra are placed side by side with their ends aligned, each quale at every point on the shifted spectrum is the shifted quale for the quale at that same point on the non-shifted spectrum. For example, in Figure II.9, Spectrum A is the non-shifted color-qualia spectrum, its qualia ordinally arranged based on their corresponding light wavelengths, and Spectrum B is the shifted-qualia spectrum obtained from shifting Spectrum A to the left.

Figure II.9 Non-shifted (A) and shifted (B) color-qualia spectra

Now, when people experiencing non-shifted color qualia see the light spectrum, they will see it as Spectrum A in Figure II.9, but people experiencing shifted color qualia will see the light spectrum as Spectrum B. Although we do not know what the color qualia in the vacated portion on the right side of Spectrum B look like, we can compare qualia in the discernible portion on the left with their counterparts in Spectrum A.

Again, because the light spectrum appears to these two people groups as different spectra, they disagree on various spectral characteristics, such as, like the previous discussions for Figure II.7, where hues change markedly along their spectra. Other examples of possible observation differences are that, in the i (510–560 nm) interval, the hues remain almost the same for people experiencing normal color qualia but obviously change for people experiencing shifted color qualia and that, in the ii (590–640 nm) interval, the hues change notably for people in the normal group but continue almost unchanged for the people in the shifted group. Therefore, if shifted color qualia occur among people, they will be able to tell, based on their observations, that they are seeing different qualia spectra of the same light spectra. Yet, this kind of discrepancy does not happen. This is evidence that shifted color qualia of this form do not occur in humans.

The general relationship characteristics between normal and shifted pitch qualia are similar to those between normal and shifted color qualia. However, in the case of pitch qualia, even if pitch qualia are shifted up or down along their spectra in some people, we will not be able to tell that they are experiencing pitch qualia that are different from those we experience. This is because shifted pitch qualia have the characteristics of the next type of restrictedly variable qualia—identical-structure qualia—which enable them to occur among people without people knowing that they are experiencing variable qualia.

II.2.2.3 Identical-structure qualia

Other types of inverted or shifted qualia may occur among people; please see more discussions about this matter in Reference 1. However, one type of variable qualia that can theoretically occur in people without people being able to tell that they are experiencing variable qualia is identical-structure qualia. Identical-structure qualia come in sets. Each set occurs in a single individual and comprises qualia with manifestations, such as colors or pitches, different from their counterparts in other sets. However, all sets have identical qualia structures; that is, they have the same number and types of basic qualia components and the same spectral characteristics (please see more details about the qualia structure in PQ2.6, Chapter 4). One example of identical structure qualia is the shifted pitch qualia. Shifted pitch qualia in each set have pitches that are shifted higher or lower along their spectra relative to their counterparts in other sets. However, other sound characteristics are the same. Shifted pitch qualia in all sets have the same number and types of basic qualia components—pitch, loudness, timbre, formant, attack, sustain, decay, and release. Their spectral characteristics are also identical. For example, the identical regular repetition of the sound of each note at every doubling or halving of its sound frequency along the scale (but in different octaves) and the identical acoustic relations among notes (such as the major third, perfect fourth, and perfect fifth are consonant intervals; the minor second, major second, and tritone are dissonant intervals) are identical in all sets of shifted pitch qualia. These identities render similar chords and songs (those constructed from similar notes) among all sets of shifted pitch qualia sound the same. Consequently, all sets of shifted pitch qualia behave identically, and people would not be able to tell if they are experiencing different pitch qualia. 

Next is an instructive and interesting matter. Like other variable qualia discussed previously, each set of identical-structure qualia can form a spectrum with manifestation parameters (such as frequencies or wavelengths) arranged ordinally, as discussed before. Again, for the set of normal color qualia, this spectrum resembles the light spectrum, depicted as Spectrum A in Figure II.10. Now, other sets of identical-structure color qualia consist of color qualia that we do not know what they are like. Thus, we cannot show them correctly here; we can only represent them as Spectrum B, which is arbitrarily illustrated as a gray panel, in Figure II.10.

Figure II.10 Two identical-structure color-qualia spectra

The essential point is that the qualia in both spectra have the same number and types of basic qualia components: color, brightness, shape, dimension, and movement. The spectral characteristics, including all internal relationships among the qualia in each spectrum, are the same. For example, how colors change their hues along the spectrum (such as distinct changes in hues around wavelengths of 410, 470, 490, 570, and 610 nm) is the same, the apparent brightness at each wavelength along the spectrum is the same, and the perceived hue change in any interval (e.g., an indistinct hue change in the i interval and a clear hue change in the ii interval) is the same. Thus, if such identical structure color qualia occur among people, they will not be able to tell that they are experiencing different color qualia.

Regarding the puzzle of whether your red is my blue, if we both experience identical-structure qualia, it will make no difference whether that is the case because, even if your red is my blue, the spectral characteristics of the color qualia in our minds will be identical, rendering the relationships between colors in your spectrum the same as those in my spectrum. This will make every aspect of your experience of your spectrum identical to that of mine. This conclusion can be explained more clearly with an illustration as follows:

Please see Figure II.11. Suppose you experience a set of normal color qualia and I, another set of identical structure color qualia. Spectrum A will represent how you see the light spectrum, and Spectrum B will represent how I see the same light spectrum. In my spectrum, a color quale at each wavelength will be different from the corresponding one in your spectrum. Like identical-structure qualia in Spectrum B in Figure II.10, my color qualia, except blue, cannot be depicted but are represented arbitrarily by gray color.

Figure II.11 Your (upper) and my (lower) light spectrum qualia

Now, even if I see the color of the 700 nm light as blue, while you see it as red (i.e., your red is my blue), it will be that, while you see the color of the 590 nm light as yellow, which is less warm than your red, I will not see it as yellow, which is warmer than my blue, but will see it as some color that is, similar to your case, less warm than my blue. We will have similar experiences with this pair of color qualia (red vs. yellow in your case and blue vs. some color in mine). What is this “some color”? The answer is that it will probably be a color that does not exist in your spectrum, even though it does in mine. Similarly, while you see the color of the 440 nm light as blue, which is much darker and cooler than your red, I will not see it as blue or back to red (which would make your blue my red); I, like you, will see it as some color that looks much darker and cooler than my blue. Again, we will have similar experiences with this pair of colors (red vs. blue in your case and blue vs. some color in mine). What is this “some color”? Once again, the answer is that it will probably be a color that does not exist in your spectrum, even though it does in mine.

Thus, it does not matter whether your red is my blue because, even if it is, my blue will relate to other colors in my spectrum exactly as your red does to other corresponding colors in yours, effectively making my blue appear and behave as if it were red in my spectrum. The same principle applies to all other colors in both spectra. Consequently, both spectra will provide us with identical experiences. We will perceive the two spectra identically, such as seeing hues change markedly at the same points along the spectra and observing hue differences in any wavelength interval similarly. This is true for all other identical structure qualia of any type (sound, smell, taste, etc.). Therefore, it does not matter whether identical-structure qualia occur because we will never experience them differently or be able to notice and differentiate them, and they will never have different effects on us. Our worlds will be virtually identical, even if these identical structural qualia occur.

II.3 Summary

From the current evidence, it can be concluded that, in reality,

• physically originated variable qualia can occur,
• randomly variable qualia-complete (RVQc) do not occur,
• randomly variable qualia-partial (RVQp) do not occur, and
• restrictedly variable qualia in some forms, such as inverted qualia and shifted color qualia, do not occur, but in some forms, such as identical-structure qualia, may occur, and behaviorally, people will not be able to tell that they are experiencing identical-structure qualia.

However, it is important to note that identical-structure qualia are restrictedly variable qualia—they cannot occur haphazardly but must occur in some restricted ways, with some rules governing their manifestations. The governing rules are as follows:

1. They must have different phenomenal manifestations among people.
2. They must have the same number and types of basic qualia components in all people.
3. They must have the same spectral characteristics in all people.

In humans, the number and types of basic qualia components of each type of quale are fixed and differ from those of other types. For example, visual qualia always have five basic components: color, brightness, shape, dimension, and movement. In contrast, auditory qualia always have eight basic components: pitch, loudness, timbre, formant, attack, sustain, decay, and release; olfactory qualia always have two basic components: odor type and strength. Moreover, the spectral characteristics of each type of quale are different from those of other types and may be very complex and peculiar, such as the spectral characteristics of color qualia of the light spectrum, which have hues and brightness changes idiosyncratically along the spectrum, and the spectral characteristics of pitch qualia, which have similar sounds repeated in different octaves regularly at every doubling frequency. Therefore, if identical-structure qualia do occur, the physical problem about them will be: What is the mechanism that makes those qualia manifest themselves differently among different people yet at the same time manifest themselves restrictedly correctly so that they have not only the same number and types of basic components but also the same unique spectral characteristics of that type of quale among billions of different individuals at different places and different times? And the philosophical question about them will be: Why should qualia manifest themselves differently only in some restricted ways, why not in a totally random way, as RVQc do, or why not “not differently” at all?

II.4 Remarks

Theoretically, because the signaling patterns of perception neural processes in different people perceiving the same things under the same conditions are similar and because, according to Theorem IV, those signaling patterns are qualia, qualia (of the same things) in different people are similar. Therefore, according to this theorem, all variable qualia that are not physically originated do not occur. These are the predictions of this theory. Please see their details in Section 10.1.

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References

1. Byrne A. Inverted qualia. In: Zalta EN, editor. The Stanford Encyclopedia of Philosophy (Winter 2016 Edition). https://plato.stanford.edu/archives/win2016/entries/qualia-inverted/
2. Chalmers DJ. Absent qualia, fading qualia, dancing qualia. In: The conscious mind: In search of a fundamental theory. Oxford: Oxford University Press; 1996:247–275. https://personal.lse.ac.uk/ROBERT49/teaching/ph103/pdf/Chalmers_The_Conscious_Mind.pdf
3. Dennett DC. Quining qualia. In: Marcel AJ, Bisiach E (editors.). Consciousness in Contemporary Science. Oxford University Press; 1988. Reprinted in: Lycan W, editor. Mind and Cognition. A Reader, MIT Press; 1990, and in: Goldman A, editor. Readings in Philosophy and Cognitive Science. MIT Press; 1993. https://ase.tufts.edu/cogstud/dennett/papers/quinqual.htm
4. Banissy MJ, Jonas C, Kadosh RC. Synesthesia: An introduction. Front Psychol. 2014;5:1414. doi: 10.3389/fpsyg.2014.01414. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4265978/
5. Carmichael DA, Julia Simner J. The immune hypothesis of synesthesia. Front Hum Neurosci. 2013;7:563. doi: 10.3389/fnhum.2013.00563. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3769635/
6. Hänggi J, Wotruba D, Jäncke L. Globally altered structural brain network topology in grapheme-color synesthesia. J Neurosci. 2011 Apr 13;31(15):5816–5828. https://doi.org/10.1523/JNEUROSCI.0964-10.2011 http://www.jneurosci.org/content/31/15/5816.long
7. Hubbard EM. Neurophysiology of synesthesia. Curr Psychiatry Rep. 2007 Jun;9(3):193–199. https://www.hal.inserm.fr/file/index/docid/150599/filename/Hubbard_CurrPsychReports.pdf
8. Hubbard EM, Ramachandran VS. Neurocognitive mechanisms of synesthesia: A review. Neuron. 2005 Nov 3;48:509–520. doi: 10.1016/j.neuron.2005.10.012. http://cbc.ucsd.edu/pdf/neurocog_synesthesia.pdf
9. Neckar M, Bob P. Neuroscience of synesthesia and cross-modal associations. Rev Neurosci. 2014;25(6):833–840. https://docksci.com/neuroscience-of-synesthesia-and-cross-modal-associations_5ad13d37d64ab209061dd85a.html
10. Neufeld J, Sinke C, Zedler M, et al. Disinhibited feedback as a cause of synesthesia: Evidence from a functional connectivity study on auditory-visual synesthetes. Neuropsychologia. 2012 Jun;50(7):1471–1477.
11. Ro T, Ellmore TM, Beauchamp MS. A neural link between feeling and hearing. Cereb Cortex. 2013 Jul;23(7):1724–1730. doi: 10.1093/cercor/bhs166. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3673182/
12. Rothen N, Terhune DB. Increased resting state network connectivity in synesthesia: Evidence for a neural basis of synesthetic consistency. J Neurosci. 2012 Oct 3;32(40):13641–13643. https://doi.org/10.1523/JNEUROSCI.3577-12.2012 http://www.jneurosci.org/content/32/40/13641.long
13. Rouw R, Scholte SH. Neural basis of individual differences in synesthetic experiences. J Neurosci. 2010 May 5;30(18):6205–6213. https://doi.org/10.1523/JNEUROSCI.3444-09.2010  http://www.jneurosci.org/content/30/18/6205.long
14. Rouw R, Scholte HS, Colizoli O. Brain areas involved in synaesthesia: A review. J Neuropsychol. 2011 Sep;5(2):214–242. doi: 10.1111/j.1748-6653.2011.02006.x. http://mobile.www.daysyn.com/Rouwetal2011.pdf
15. Neufeld J, Sinke C, Dillo W, et al. The neural correlates of coloured music: A functional MRI investigation of auditory–visual synaesthesia. Neuropsychologia. 2012;50:85–89. http://www.daysyn.com/neufeld_j_et_al_2012.pdf
16. Tomson SN, Narayan M, Allen GI, Eagleman DM. Neural networks of colored sequence synesthesia. J Neurosci. 2013 Aug 28;33(35):14098–14106. doi: 10.1523/JNEUROSCI.5131-12.2013. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4050198/
17. van Leeuwen TM, den Ouden HEM, Hagoort P. Effective connectivity determines the nature of subjective experience in grapheme-color synesthesia. J Neurosci. 2011 Jul 6;31(27):9879–9884. doi: 10.1523/JNEUROSCI.0569-11.2011. http://www.jneurosci.org/content/31/27/9879.long
18. van Leeuwen TM, Singer W, Nikolić D. The merit of synesthesia for consciousness research. Front Psychol. 2015;6:1850. doi: 10.3389/fpsyg.2015.01850. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4667101/
19. Ward J. Synesthesia. Annu Rev Psychol. 2013;64:49–75.
20. Ward J, Mattingley JB. Synaesthesia: An overview of contemporary findings and controversies. Cortex. 2006 Feb;42(2):129–136. http://acces.ens-lyon.fr/acces/thematiques/neurosciences/actualisation-des-connaissances/memoire-attention-et-apprentissage/neuros_apprentissage/neuro_apprentiss_2/dossier_hupe/Ward
21. Zamm A, Schlaug G, Eagleman DM, Loui P. Pathways to seeing music: Enhanced structural connectivity in colored-music synesthesia. Neuroimage. 2013 Jul 1;74:359–366. doi: 10.1016/j.neuroimage.2013.02.024. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3643691/
22. Hupé JM, Bordier C, Dojat M. The neural bases of grapheme–color synesthesia are not localized in real color-sensitive areas. Cereb Cortex. 2012;22(7):1622–1633. https://doi.org/10.1093/cercor/bhr236 https://academic.oup.com/cercor/article/22/7/1622/293312/The-Neural-Bases-of-Grapheme-Color-Synesthesia-Are
23. Hupé JM, Dojat M. A critical review of the neuroimaging literature on synesthesia. Front Hum Neurosci. 2015 Mar 31;9(103):1–45. doi: 10.3389/fnhum.2015.0010. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4379872/
24. Dragoi V. Chapter 15: Visual processing: cortical pathways. In: Neuroscience Online. The University of Texas. Health Science Center at Houston (UTHealth). http://nba.uth.tmc.edu/neuroscience/s2/chapter15.html
25. Fitzpatrick D, Mooney RD. Chapter 12. Central visual pathway. In: Purves D,‎ Augustine GJ,‎ Fitzpatrick D,‎ Hall WC,‎ LaMantia AS,‎ Mooney RD, Platt ML, White LE, editors. Neuroscience. 6th ed. New York: Oxford University Press; 2018:261–280.
26. Bartolomeo P, Bachoud-Lévi AC, Thiebaut de Schotten M. The anatomy of cerebral achromatopsia: A reappraisal and comparison of two case reports. Cortex. 2014 Jul;56:138–144. doi: 10.1016/j.cortex.2013.01.013. https://www.researchgate.net/profile/James_Pickles/publication/273787629_Auditory_pathways_Anatomy_and_physiology/links/571781ab08ae09ceb264aa17.pdf
27. Kölmel HW. Pure homonymous hemiachromatopsia. Findings with neuro-ophthalmologic examination and imaging procedures. Eur Arch Psychiatry Neurol Sci. 1988;237(4):237–243.
28. Paulson HL, Galetta SL, Grossman M, Alavi A. Hemiachromatopsia of unilateral occipitotemporal infarcts. Am J Ophthalmol. 1994 Oct 15;118(4):518–523.
29. Short RA, Graff-Radford NR. Localization of hemiachromatopsia. Neurocase. 2001;7(4):331–337.
30. Levin J. Functionalism. In: Zalta EN, editor. The Stanford Encyclopedia of Philosophy (Fall 2018 Edition). https://plato.stanford.edu/archives/fall2018/entries/functionalism/
31. Schoettle T. How I learned to stop worrying and love the inverted spectrum. Pacific Philosophical Quarterly. 2009;90:98–115. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1468-0114.2009.01330.x
32. Shoemaker S. The inverted spectrum. Journal of Philosophy. 1982 Jul;79:357–381. https://www.andrew.cmu.edu/user/kk3n/80-300/shoemaker-spectrum.pdf

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