From Wikipedia, the free encyclopedia

Mary's room (also known as Mary the super-scientist) is a philosophical thought experiment proposed by Frank Jackson in his article "Epiphenomenal Qualia" (1982) and extended in "What Mary Didn't Know" (1986). The argument it is intended to motivate is often called the Knowledge Argument against physicalism—the view that the universe, including all that is mental, is entirely physical. The debate that emerged following its publication recently became the subject of an edited volume—There's Something About Mary (2004)—which includes replies from such philosophical luminaries as Daniel Dennett, David Lewis, and Paul Churchland.

Contents 1 The thought experiment 2 Implications 2.1 Qualia 2.2 The knowledge argument 3 Responses 3.1 Daniel Dennett 3.2 Frank Jackson 3.3 Ramachandran and Hubbard 4 Notes 5 References and further reading 6 See also 7 External links

The thought experiment was originally proposed by Frank Jackson as follows:

“

Mary is a brilliant scientist who is, for whatever reason, forced to investigate the world from a black and white room via a black and white television monitor. She specializes in the neurophysiology of vision and acquires, let us suppose, all the physical information there is to obtain about what goes on when we see ripe tomatoes, or the sky, and use terms like ‘red’, ‘blue’, and so on. She discovers, for example, just which wavelength combinations from the sky stimulate the retina, and exactly how this produces via the central nervous system the contraction of the vocal chords and expulsion of air from the lungs that results in the uttering of the sentence ‘The sky is blue’. [...] What will happen when Mary is released from her black and white room or is given a color television monitor? Will she learn anything or not? [1]

”

In other words, we are to imagine a scientist who knows everything there is to know about the science of color, but has never experienced color. The interesting question that Jackson raises is: Once she experiences color, does she learn anything new?

Whether Mary learns something new upon experiencing color has two major implications: the existence of qualia and the knowledge argument against physicalism.

First, if Mary does learn something new, it shows that qualia (the subjective, qualitative properties of experiences), exist. If we agree with the thought experiment, we believe that Mary gains something after she leaves the room—that she acquires knowledge of a particular thing that she did not possess before. That knowledge, Jackson argues, is knowledge of the qualia of seeing red. Therefore, it must be conceded that qualia are real properties, since there is a difference between a person who has access to a particular quale and one who does not.

Second, if Mary does learn something new upon experiencing color, physicalism is false. Specifically, the Knowledge Argument is an attack on the physicalist claim about the completeness of physical explanations of mental states. Mary may know everything about the science of color perception, but can she know what the experience of red is like if she has never seen red? Jackson contends that, yes, she has learned something new, via experience, and hence, physicalism is false. Jackson states:

“

It seems just obvious that she will learn something about the world and our visual experience of it. But then is it inescapable that her previous knowledge was incomplete. But she had all the physical information. Ergo there is more to have than that, and Physicalism is false.[2]

”

It is important to note that in Jackson's article, physicalism refers to the epistemological doctrine that all knowledge is knowledge of physical facts, and not the metaphysical doctrine that all things are physical things.

Daniel Dennett argues that Mary would not, in fact, learn something new if she stepped out of her black and white room to see the color red.^[3] Dennett asserts that if she already truly knew "everything about color", that knowledge would include a deep understanding of why and how human neurology causes us to sense the "qualia" of color. Mary would therefore already know exactly what to expect of seeing red, before ever leaving the room. Dennett argues that although we cannot conceive of such a deep knowledge, if a premise of the thought experiment is that Mary knows all there is to know about color, we cannot assume that we can fathom or even describe such knowledge—or that such knowledge doesn't exist.

Frank Jackson initially supported the anti-physicalist implications of the Mary's room thought experiment. Jackson believed in the explanatory completeness of physiology, that all behaviour is caused by physical forces of some kind. And the thought experiment seems to prove the existence of qualia, a non-physical part of the mind. Thus, Jackson argued, that if both of these theses are true, then epiphenomenalism is true—the view that mental states are caused by physical states, but have no causal effects on the physical world.^[4]

Explanatory completeness            qualia  
    of physiology              +  (Mary's room)      =   epiphenomenalism

Thus, at the conception of the thought experiment, Jackson was an epiphenomenalist. Later, however, he rejected epiphenomenalism.^[5] This, he argues, is due to the fact that when Mary first sees red, she says "wow", so it must be Mary's qualia that causes her to say "wow". This contradicts epiphenomenalism. Since the Mary's room thought experiment seems to create this contradiction, there must be something wrong with it. This is often referred to as the "there must be a reply, reply".

V.S. Ramachandran and Edward Hubbard of the Center for Brain and Cognition at UCSD argue that Mary might do one of three things upon seeing a red apple for the first time:

1. Mary says she sees nothing but gray.
2. She has the "Wow!" response from subjectively experiencing the color for the first time.
3. She experiences a form of blindsight for color, in which she reports seeing no difference between a red apple and an apple painted gray, but when asked to point to the red apple, she correctly does.

They explain further: "Which of these three possible outcomes will actually occur? We believe we've learned the answer from a colorblind synesthete subject. Much like the theoretical Mary, our colorblind synesthete volunteer can not see certain hues, because of deficient color receptors. However, when he looks at numbers, his synesthesia enables him to experience colors in his mind that he has never seen in the real world. He calls these "Martian colors." The fact that color cells (and corresponding colors) can activate in his brain helps us answer the philosophical question: we suggest that the same thing will happen to Mary."^[6]

• Dennett, Daniel. 1991. Consciousness Explained, Boston: Little Brown.
• Dennett, Daniel. 2003. "What RoboMary Knows", in Torin Alter (ed.) Knowledge Argument. Online text
• Jackson, Frank. 1982. "Epiphenomenal Qualia", Philosophical Quarterly 32, pp. 127-136. Online text
• Jackson, Frank. 1986. "What Mary Didn't Know", Journal of Philosophy 83, pp. 291-295.
• Ludlow, P., Y. Nagasawa, and D. Stoljar (eds.). 2004. There's Something About Mary, MIT Press.

• Dualism (philosophy of mind)
• Inverted spectrum
• Functionalism
• The map is not the territory
• Philosophy of mind
• Philosophy of perception
• Physicalism
• Qualia
• Subjective character of experience
• Zombies

• "Qualia: The Knowledge Argument" - an article by Martine Nida-Ruemelin on the Stanford Encyclopedia of Philosophy.
• "The Knowledge Argument Against Physicalism" - an article by Torin Alter on the Internet Encyclopedia of Philosophy.