Constructing Sandcastles Out Of Mud

Constructing Sandcastles Out Of Mud Why the Inverted Spectrum argument does not adequately disprove functionalism

Bryan Kennedy Philosophy of Mind Prof. John Searle 7/29/03

The Inverted Spectrum argument is one of the primary critiques opposing the functionalist theory of mind. But what exactly is this argument, and why is it considered a decisive case against functionalism? In this essay, I will answer these questions, and attempt to demonstrate why the Inverted Spectrum argument does not adequately refute the functionalist position. I will do this by holding that functionalism can account for the hypothetical situation posed by the argument, and demonstrating that the condition it proposes could not exist in the world. Color is integral to our daily lives. Every object that we observe and interact with has a color – the apple on my desk is green, my keyboard is a silvery blue, and my computer screen glows with a vibrant array of hues. For each color that I see, I experience an inner feeling, or qualia, whenever I view it that is distinct from all the other colors that I can perceive or imagine. In the theory of functionalism, minds operate through a step-by-step interaction with their environment. That is, mental states are described through their relation to three main states: 1) sensory input, 2) internal states or qualia, and 3) external states or behavior. Mental life, according to functionalist theory, works much like that of a mathematical algorithm – external experiences, combined with various internal mental operations, lead to behavioral outputs (Lewis, 1980). A functionalist would assert that when I see a green object, my mind first experiences the sensory input as photons of light detected by my eyes. In turn, this input is converted into various internal mental states, such as a quale of greenness, which is perhaps connected to further mental qualia (nature, good, edible). All of these qualia eventually give rise to my behavioral effects, such as exclaiming “Now that’s a green Granny Smith!” But what if my green quale is not the same as yours? It seems plausible to suggest that we both might see the same object, and react in the same way, but have completely different internal states. Since the underlying basis of functionalism is that of causal relations, would that not throw off the functionalist equation? Enter the Inverted Spectrum argument; while it takes on many different forms, the fundamental situation it proposes is this: Consider the case of Sally Invert. From the outside, Sally appears to be a perfectly normal student at Cal: she hangs out with her friends, watches action-adventure movies, and does all of her Philosophy of Mind reading. Essentially, her “input” and

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“output” are functionally indistinguishable from that of her peers. But our Sally is different because she has inverted vision. Her reds are greens, her yellows, blues. Sure, the sight of a beautiful summer sunset brings tears to her eyes and conjures up happy memories of childhood; but to her, the most salient color of the setting sun is a deep, vibrant green, which fades into a pale, darkening yellow. Nonetheless, when describing the sunset, she is indistinguishable from her peers; her yellow quale is perfectly linked to the word “blue”, her green quale, perfectly linked to “red”. Thus no one, including her, is aware of her unfortunate condition (Searle, 1992). Assuming for a moment that this is indeed an accurate description of Sally’s qualia, the functionalist equation breaks; not only does she receive the same input as you and I, but her behavior is identical to ours. Thus, the functionalist contention that her internal states are the same as ours is flawed, since there is nothing else “entering into” the equation that could counteract the difference. This train of thought leads us to the conclusion that there must be something else going on in Sally’s mind other than simple causal algorithms. On the surface, this is a strong argument against the functionalist theory of mind, but I am not so easily convinced. On first blush, the argument itself seems plausible. Everyone at one time or another has wondered if they might see colors differently than the rest of the world – after all, if “green” is simply a linguistic translation of our mental qualia, it seems plausible to suggest that my “green” is your “red”, and vice versa. Assuming for a moment that indeed such a case exists in the real world, I will show that a color distinction of this sort is of no consequence to the functionalist theory of mind. In the perfect fingerpaint world of a kindergartener’s imagination, colors do have direct mappings: blue goes with yellow, and green goes with red. But what is a color wheel anyway, other than the imperfect realization of color for artistic purposes? And what are colors really, beyond our internal representations of the external world? Are green trees actually “green”, blue cars really “blue”, or red sunsets truly “red”? No, in reality, colors causally reduce to their photonic properties – it is we who ascribe meaning to these properties. Certainly, it is quite easy to imagine (and in fact name) creatures that do not share our same sensitivity to light. Snakes, for instance, are capable of perceiving infrared light, and cats, it is known, cannot easily differentiate between red and green

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hues (Veterinary Vision, 1998). Does this mean that they share our same set of color qualia with certain components missing or added (the assumption that they do indeed have qualia must necessarily be the subject of a future paper), or more likely, that they actually have completely distinct qualia to ours? Indeed, our perception of color relies on our specific sensory apparatus to sense it, which in turn allows us to differentiate colors in the way that we do. At the most focused level of causal reduction, the “color” red is nothing more than packets of photons of specific energies, bouncing off from an object that doesn’t absorb them (Coren etc al, 1999). In that sense, the green apple I ate earlier was quite colorless – it was my mind that created the perception of its green hue, due to the physiological makeup of my eyes. Moreover, we find that there is always a direct one-to-one mapping of color input to internal qualia. The green apple doesn’t appear red when I’m angry or blue when I’m sad. That being so, if my “green” quale replaced my “red” quale in all cases, it would actually make no functional or qualitative difference to me. Red would still be “red”, green would be still be “green”, and both would still carry the same qualitative properties and connections in my mind. When this observation is combined with the fact that color boundaries are constructed within my mind, rather than being a true artifact of the world, I am led to believe that Sally Invert’s qualia don’t in fact differ from our own. Consider the case of my changing the font on this paper from “Times New Roman” to “Trebuchet”: the appearance of the essay would change dramatically, but its meaning, or semantics, would remain the same. We can imagine Sally’s reverse qualia by comparing it with our own, but without such grounds for comparison, the distinction fails. She’s still going to look upon the color of my green apple as I do, and associate my red with fire and danger. So qualitatively speaking, there is nothing going on in her mind that is different from mine. That being said, the Inverted Spectrum argument seems to miss the point of functionalism entirely – an integral conclusion of functionalism states that minds can exist in a variety of substrates. So even if a Sally exists in the world, and her qualia differ from ours, and this distinction is important (both points are under contention here), it can be concluded that Sally’s particular brain makeup allows for this distinction on a physical level. Put another way: if the input and output of two minds are the same, but the internal

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states differ, functionalist theory permits that the minds be implemented differently. A functionalist would put forward the example of the same simple calculator program implemented on a Mac and a PC. While they look and function alike, the code behind each is completely different. Likewise, Sally’s “code” may give rise to different qualia, but this does not suggest that Sally differs functionally from a “normal” person. Taking this a step further, some functionalists would argue against the discussion of qualia itself; instead proposing that our specific qualitative experiences are only differentiated by the causal connections they make in our minds. Red is only red because of the feelings of danger, blood, and fire it incites. Thus, it is meaningless to suggest that red might really be green, because if it still shares all the same connections, it is. Even more fundamental to the argument against spectrum inversion, however, is the fact that it would involve a loss of information about the world. Like I have stated before, colors are linguistically, and perhaps neurologically, defined. Thus, in a true invert, there would be countless cases where the names of colors do not line up with their inverted spectrum counterparts. In color blindness, there is a loss of information of the external world, which leads to easy diagnosis – reds and greens become all but indistinguishable. In the hypothetical color-invert however, it is presupposed that there is no loss of information. This suggests that the condition would go undiagnosed, implying that there may indeed be people like Sally Invert in our midst. In fact, this is the key to the Inverted Spectrum argument – Sally must behave in exactly the same manner as I, or else she would be functionally different and therefore compatible with functionalist theory. But would a true color invert evade detection, or would their symptoms necessarily show up in their daily encounters with color? Contrary to what your kindergarten teacher may have led you to believe, the color spectrum as linguistically constructed has no inverse: inverted dark blue is not dark yellow, but brown. When I view my mental qualia of dark blue and light blue in a side-by-side comparison with yellow and brown, I find their relationships differ by a large semantic margin. See Figure 2a to experience this distinction. Given this finding, would Sally Invert function as everyone else given the stimulus of tropical beach scene – with brown dirt fading to yellow sand? Obviously no. As figure 2b illustrates, Sally would have one central quale (dark blue and

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blue) for two distinct linguistic terms (brown and yellow). Thus, she would consistently find herself on the uncomfortable linguistic edge between color distinctions, and her friends would wonder why she always insisted on building sandcastles out of dirt. Now turning our attention to Figure 1, a young Sally paints with friends. Notice how Sally’s red paint and her friend’s brown skin are resolved to an almost universal shade of blue in the inversion case. In our normal perception of color, browns are very distinct from reds and yellows; while in an inverted spectrum, this distinction does not hold. Sally’s parents, upon discovering her difficulty in distinguishing between apples and people, would take her in for treatment, and a new disorder, named Invert Blindness after our dear Sally Invert, would gain the scientific attention it deserves. Until this disorder shows up in my monthly copy of Psychology Today however, I will have serious doubts as to its existence. One of the central arguments leveraged against Functionalism is that of the possibility of an inverted spectrum. I have attempted to show here that not only can functionalism account for such hypothetical phenomena, but a color invert would indeed demonstrate functional differences in their perception of color. Are there other valid arguments against functionalism? Certainly; but neither the input provided to me in the assignment, nor my internal beliefs and desires, led me to behave in such as a way as to disprove them as well.

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Figure 1: Sally Invert as a young girl

“Normal” Color Perception

Simulated Color Inversion

Red-Green Color-blindness

The simulated color inversion picture was created in Photoshop 7 using the Channel Mix technique as described on creativepro.com, which essentially switched the red/green and blue/yellow color channels. This is about as close as one can get to experiencing how a color invert would view the world. Original image of girl from “Corbis: Kids" stock image gallery.

Figure 2: Color Squares Comparing Blue/Blue with Yellow/Brown

“Normal” Condition

Inversion Condition

These color boxes were created in Photoshop 7 using the standard color picker on a Hue-Saturation-Brightness scale. The top-left color is the blue condition, the top-right color the yellow condition. The bottom colors differed from their upper counterparts by -10 degrees saturation, and -40% brightness. The inversion condition was arrived at through the same method described above.

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Work Cited Coren, Stanley, et al. Sensation and Perception. New York: Harcourt Publishers, 1999. Lewis, David. “Mad Pain & Martian Pain.” Readings in Philosophy of Psychology. Ed. Ned Block.: 1980, 216-222. Searle, John R. The Rediscovery of the Mind. Cambridge, Mass.: Bradford, 1992. “What Do Dogs and Cats See?” (1998). Veterinary Vision: Animal Eye Specialists. Retrieved: 22 July, 2003. Online: http://www.veterinaryvision.com/See.htm

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