Physicalism VS Consciousness, Winner Takes All.

Do you believe reality is fundamentally physical or do you believe that consciousness is real? You cannot have both. You must choose a side.

Feb 28, 2023

If you take physicalism, the position that everything is fundamentally physical, to its logical conclusion, there is no such thing as consciousness. Notable proponents of such a view are Daniel Dennet and Patricia Churchland, both of whom argue that consciousness is an illusion. People from all walks of life believe that reality is primarily and fundamentally physical. In fact, outside of people who hold religious metaphysical views, physicalism is the primary view held by people. What many people who hold this view do not often realize is that to be logically consistent, they must also believe consciousness does not exist. However, what you will often find in speaking with non-philosophers is that they hold this contradicting view. They will state that the world is purely physical, as opposed to mental or some sort of mix of the two, and will claim that they definitely have consciousness. Some of them will even quote Descartes, a famous substance dualist, as proof that they are conscious. “I think, therefore I am”. Once you realize that you hold a contradicting view of reality, you have some decisions you need to make. Are you a physicalist and now need to deny your consciousness? Or are you going to hold onto your consciousness as being real and now need to formulate an alternative view of what the structure of reality is? A tough task indeed. I wrote this essay to outline one of the more common defenses of consciousness realism, that is, the inverted spectrum thought experiment. The inverted spectrum thought experiment fights against ‘functionalism’, one type of position which certain physicalists take to explain mental states. If you become convinced by the end that consciousness is indeed, likely real, I offer no help in reconstructing your understanding of reality. Not to worry, however, in later essays I will outline many alternative views to physicalism to help ease your existential whirlwind.

I divide this essay into three parts: 1. I will describe what the inverted spectrum thought experiment is. However, since the inverted color spectrum thought experiment comes in many variations and is deployed with multiple uses, I will focus first on the most basic version of the thought experiment and then also describe a basic version of the intrapersonal/ interpersonal inverted color thought experiment. 2. I will then describe how the inverted spectrum thought experiment could possibly be used as an objection to the functionalist perspective on consciousness. 3. I will lastly describe how someone coming from the functionalist perspective might respond to the problem that the inverted spectrum thought experiment presents to them.

The inverted color spectrum thought experiment has many variations and is used in different ways to object to theories such as but not limited to, behaviorism, functionalism, representationalism, and physicalism more generally. In its most basic form, the inverted color spectrum thought experiment is a thought experiment that intends to highlight that one’s subjective experience of color could be completely different from the subjective experience of color that someone else is experiencing from the same stimulus. E.g. Two people are looking at the same tomato, one person experiences red and the other person experiences green. One of the more basic variations of the thought experiment starts by introducing the basic concepts of the color wheel. The most important portion to know is that the four primary colors on the color wheel sit directly opposed to each other and act as opposites. E.g. Red and green are opposites of each other and yellow and blue are opposites of each other. The experiment then supposes that someone could exist who instead of seeing the color spectrum in a ‘normal’ way, would see it in an inverted way. This inverted person would experience grass as you( the non-inverted person) experience red. They would experience the blue sky as you( the non-inverted person) experience yellow. All of their color experience would be inverted in exactly this way. All of what you experience as red is green to them and vice versa. All of what you experience as blue is yellow to them and vice versa. And so on with all possible colors (Byrne).

The inverted color spectrum thought experiment that I just presented acts as a foundation for more detailed versions of the thought experiment that are used to object to different theories of consciousness, namely, behaviorism, functionalism, representationalism, and physicalism more generally. The version of the thought experiment that I will describe is known as the intrapersonal/interpersonal variation of the inverted color spectrum thought experiment. There are multiple ways to present the intrapersonal/interpersonal thought experiment but for the sake of this essay, I will describe only one of the ways.

A paraphrased version of the classic intrapersonal/interpersonal account goes as follows: Imagine that a single individual named Vladamir wakes up one morning and his subjective experience of color is completely inverted as to how it was for the entire previous portion of his life. He now experiences grass as red and the sky as yellow and so on. (The possible explanation for how this has happened is beside the point for this essay but perhaps could be explained by a head injury, a chemical injury or something else causally relevant).

The next step is to imagine that Vladamir, now stuck in this state of inversion has begun to adapt his vocabulary to match that of the rest of the world. When he looks at the sky, he still experiences red but now calls his experience of red, blue, in order to fit in with the rest of his contemporaries. At this point, Vladamir still has the memory of what the color of things used to be before his subjective experience was inverted.

The last step of the intrapersonal account is to imagine that Vladamir, over time has now forgotten what his pre-inversion experience of color was like. (Whether it’s from another head injury, amnesia, simply time passing or any other causally relevant reason). At this point for Vladimir and all of his contemporaries, no one including Vladamir himself is aware that he subjectively experiences color in an inverted way relative to the people around him. He is behaviorally no different at this point. Only subjectively.

This essentially sums up the intrapersonal step of the intrapersonal/interpersonal account of the inverted color spectrum thought experiment. The last step of the intrapersonal/interpersonal account is to imagine that if Vladamir’s entire experience is possible, then it is possible to imagine that someone or some people could be inverted from birth and thereby subjectively experience color in an inverted way relative to people who are not inverted (Block, Shoemaker, Byrne, Lee).

Here in the second section of this paper, I aim to describe how the intrapersonal/interpersonal inverted color spectrum thought experiment could possibly be used against a functionalist perspective on consciousness. In order to show how the intrapersonal/interpersonal account may be used against the functionalist perspective, I will describe a basic outline of what the functionalist perspective of consciousness is. A basic version of what the functionalist perspective is as follows: What makes a state conscious is the functional role it plays(Lee). For example, the role/experience of pain is to make the organism(you or whatever is experiencing the pain) become aware of something that is harming it so that the organism can make an action to stop the pain and harm from happening. Another example, the role/experience of hunger is to make the organism aware that it needs nutrition so that it acts in a way that seeks nutrition and satisfies that need. Another example, the role/experience of red is to help the organism distinguish between surfaces with other colors (Lee), or associate the experience of red with certain types of events like the acquisition of a tomato and the type of nutrition associated with it or the sight of blood and the type of risk or experience associated with it, etc.

The functionalist perspective on consciousness is concerned only with how the conscious state provides a function to the organism and is not concerned with what the functional cause is made out of. E.g. The liver could be made out of organic material or it could be made out of plastic, so long as it functions as a liver, it is a liver. (Lee). This distinction highlights that the functionalist is only concerned with defining subjective experience by the causal role the subjective experience plays and not with what it is made out of.

With the functionalist perspective roughly defined, I will now describe how the inverted color spectrum can be used against it. If the inverted spectrum is indeed possible then you can imagine a scenario where two twins, Hoshi and Rina, are both looking at a collection of solid-colored marbles on the ground in front of them. (In this scenario, Hoshi is what I described earlier as someone who experiences the color spectrum in a ‘normal’ way and Rina is someone who experiences the color spectrum in an ‘inverted’ way). Hoshi then asks Rina to sort the marbles in order by color. Blue marbles first, yellow marbles second, red marbles third and so on. Rina agrees and sorts the marbles exactly in the order that Hoshi had expected. Then, Rina scrambles the marbles and asks Hoshi to rearrange them in a different order but still according to color. Green marbles first, blue marbles second, yellow marbles third and so on. Hoshi then orders the marbles in the exact way that Rina had expected. Both Rina and Hoshi are acting functionally equivalent and neither of them suspects that the other is experiencing color any differently than they themselves are.

According to the functionalist perspective, Hoshi and Rina should be having the same subjective experience of color in order to explain the equivalent functional role that both of their subjective experiences of color are having. But as stated above, Rina is subjectively experiencing color in an inverted way relative to how Hoshi is experiencing color. Therefore, the subjective experience of color, the redness of red or the blueness of blue, and so on, is not defined by its functional role. And if an organism’s subjective experience is not defined by its functional role, then functionalism is false.

Here in the third section, I aim to describe how a functionalist may respond to the

Inverted color spectrum thought experiment. The most common response from the functionalist is to deny that color inversion is actually possible. There are many angles that defenders of functionalism take in denying the possibility. One is that while the primary colors could conceivably be inverted and be functionally equivalent under inverted conditions, the more subtle colors of the spectrums could not be precisely inverted and therefore would not allow an inverted person to be functionally the same. E.g. Purple seems to be much more detectable and more easily categorized to humans than does its opposite color on the color wheel, yellow/green (Lee). Because of this, the inverted person would not be able to act functionally the same as the non-inverted person. Thereby preserving functionalism.

Another common response from the functionalist is to question the first premise of the intrapersonal thought experiment. That is, how could we distinguish if someone actually became inverted or if the person’s memory of what color looked like had actually changed (Lee). If we accept that the intrapersonal account cannot distinguish between an actual inversion and a memory flip or whether it’s even possible in the first place, then we cannot have any certainty about the possibility of an interpersonal account of color inversion either. And if it's the case that we cannot have any certainty about the possibility of interpersonal color inversion, then we have no reason to say that it’s possible for someone to be color inverted and functionally equivalent. Thereby preserving functionalism.

If you do not buy the inverted color spectrum thought experiment as something plausible, do not worry, it does not mean that you are by default a consciousness-denying physicalist. There are many more arguments defending consciousness against physicalism that I will outline later on, some more convincing than others. If you do believe that the inverted color spectrum is something that is possible, then congratulations, you believe that consciousness is real! For you, if you previously held a physicalist view of reality, now need to find a new framework of reality to place your newly defended consciousness in.

Alexander’s Substack

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