Mary the Colorblind Neuroscientist

1. Mary the Colorblind Neuroscientist

2. INTRODUCTION I present the thought experiment known as Mary the colorblind scientist. Proposed by philosopher Frank Jackson, where he attempts to provide an argument against physicalism First we have to know about Physicalism-The belief that everything including the mind is made up of physical stuff. Physical’ in this sense refers to all the realms of physical science, including chemistry, biology, neuroscience, etc.

3. Jackson • Frank Jackson (1943-present) • An Australian philosopher. • Most famous for his knowledge argument for dualism. • He has actually given up dualism now, but he still thinks the argument is valid. • He is known for giving very convincing, commonsensical arguments

4. Jackson &What Mary didn’t know • The Mary Thought Experiment: • Imagine a woman Mary • Mary is a brilliant scientist who’s been imprisoned for life in a room painted entirely black and white. • Even Mary herself is painted. • She conducts experiments (viewing the results through black and white TV) and learns every physical fact about the mind. • The physical properties of color and the eye’s response to light… • What Mary doesn’t know: • Even after Mary has learned every physical fact, she still doesn’t know what it’s like to see the color red. • Imagine what happens when she steps outside of the room for the first time and sees a ripe tomato.

5. Thought Experiments • Thought experiments: • Jackson’s example of Mary is a thought experiment. • A thought experiment is a constructed case which is used to test our intuitions about some philosophical puzzle... • So Jackson constructs the Mary thought experiment to test our intuitions about Dualism. • In particular, the Mary experiment is supposed to lead us to the intuition that Mary learns a non-physical fact…

6. Basic idea • 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? 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.

7. The Knowledge Argument • The Knowledge argument: • Jackson takes the Mary thought experiment as evidence against Physicalism • His argument is known as the Knowledge argument: • 1. Mary knows every fact about the physical world. • 2. Mary learns a fact about qualia, which she didn’t previously know, when she steps out of the black and white room. • 3. Thus, facts about qualia are facts about the nonphysical. • 4. Thus, Physicalism is false. • 5. Thus, Dualism is true.

8. Argument Two Versions of the Argument The weaker version of the knowledge argument: (1a) Mary has complete physical knowledge concerning facts about human color vision before her release.  (2a) But there is some kind of knowledge concerning facts about human color vision that she does not have before her release.  Therefore  (3a) There is some kind of knowledge concerning facts about human color vision that is non-physical knowledge.

9. The stronger version of the knowledge argument: (1b) Mary knows all the physical facts concerning human color vision before her release.  (2b) But there are some facts about human color vision that Mary does not know before her release.  Therefore  (3b) There are non-physical facts concerning human color vision.

10. The argument contained in this passage may be put like this: (1) Mary has all the physical information concerning human color vision before her release. (2) But there is some information about human color vision that she does not have before her release. Therefore (3) Not all information is physical information.  The conclusion of the stronger version of the argument (3b) is an ontological claim that the physicalist must reject. The conclusion of the weaker version of the argument is merely an epistemological claim that is compatible with denying the existence of non-physical facts. Although Jackson’s original formulation in terms of information is open to both interpretations it is clear that the second stronger version is what he had in mind. As many have pointed out, the result of the weaker version (3a) does not imply the result of the stronger version (3b).

11. Experience color for the first time in her life Mary is a scientist, who was born only being able to see in black and white. However she has devoted her life to researching everything she can about light and vision. She knows about the different wave lengths of light, and how they effect our retinas producing different shades. As well as all the other physical properties of light and how it effects us. One day, Mary undergoes a corrective surgery to fix her colorblindness, waking up to experience color for the first time in her life. • One day, Mary escapes her monochrome room, and as she walks through the grey city streets, she sees a red apple for the first time. • What changes upon Mary’s encounter with the red apple? Has Mary learnt anything new about the colour red upon seeing the colour for the first time? Since Mary already knew everything about the physics and biology of colour perception, she must surely have known all there is to know about the colour red beforehand. Or is it possible that some facts escape physical explanations?

12. Why does Mary's learning something when she leaves the black and white room pose a problem for Physicalism? If physicalism were true, then Mary would know everything about human color vision before leaving the room. But intuitively, it would seem that she learns something new when she leaves. She learns what it's like to see colors, that is, she learns about qualia, the properties that characterize what it's like.

13. The Ability hypothesis • The Second Physicalist response: Mary doesn’t learn a new fact: • Mary doesn’t learn a new fact, she acquires the ability to distinguish red things from dark grey things… • Riding a bike: • Learning to see red is like learning to ride a bike: they can’t be learned in a book… • So Knowing how to do something is not the same as knowing that something is true. • Jackson’s reply: • But Mary always had the ability to distinguish red things from dark grey things. • Is this response adequate?

14. Epiphenomenalism • Epiphenomenalism: • A thing is epiphenomenal if and only if it can be caused by other things, but never causes anything itself. • According to Jackson, Qualia are epiphenomenal. • Qualia are caused by physical states, such as brain states, but they do not have any physical effects. • So there are two types of Dualists: • Interactionists like Descartes: the non-physical aspects of the mind have physical causes and physical effects. • Epiphenomenalists like Jackson: the non-physical aspects of the mind have physical causes but no physical effects.

15. Epiphenomenalism and beliefs • Although the Epiphenomalist thinks Qualia are non-physical states, he does allow that some mental states are physical states. • Belief states and desire states are physical states: • According to the Epiphenomenalist, only physical states can cause other physical states. • And Belief states and Desire states are physical states because they cause actions. • Beer in the fridge example…

16. Physicalism and Qualia • Qualia are a problem for Physicalism: • How should the Physicalist think about qualia? • What should the Physicalist say about inverted qualia? • How should the Physicalist reply to the knowledge argument? Two options: • Mary wouldn’t learn anything new when she leaves the black and white room. • Mary would learn something, but not a new fact.

17. Denying the Intuition • The first Physicalist response is to Deny the intuition: • Some physicalists deny that Mary would learn anything new when she leaves the black and white room. • The point of the description of the case, the black and white room, etc., was to get us to have the intuition that she would say ‘Ah, ha!…’. • But we can only have the intuition if we are genuinely able to imagine the case as described. • Maybe we can’t imagine Jackson’s Mary experiment: • …because we can’t imagine what someone would do who knew every physical fact. • Jackson’s reply: • but you only have to imagine Mary knows every relevant fact.

18. Conclusion The question is, did Mary learn anything when she woke up? Jackson claims that she did, and that it shows us scientific explanations and physical properties can not account for everything there is to know about life. Debate is still hot on the subject, I could fill a book with all of it. Some claim that she did not learn anything, but simply gained an ability to see what she already learned. Some claim that color is a physical property, but then we must ask is seeing color and experiencing color the same thing? Like usual, there is no consensus on a correct answer I can give you. But I would highly recommend looking into other perspectives if it interests you.