When we talk about knowledge argument, Frank Jackson's paper "What Mary didn't know" must be mentioned. he constructs a thought experiment disproving physicalism. Honestly, I am inspired by his argument for the first time reading. However, something odd exists. But I am not able to find out atthat time. Since I dive into the paper, I probably dig out a fault which might save physicalism. Paving the way for my argument, I will take abrief review of physicalism and thought experiment. Then I will reconstruct the thought experiment and point out the probable false. Finally, I list a possible response given by Frank Jackson.

Brief review

The physicalism is claimed that all facts can be reduced to physicalfacts. This claim can be extended that if one knows all physical facts, then she/he knows everything there is to know.

Frank Jackson disagrees. In his thought experiment, Mary the scientist(MTS) spends her alllife in the Black-White Room. In the room, she learns everything "through black-and-white books and through lectures relayed onblack-and-white television."1 In this way, she learns all the physical facts about color. She specializes in neuroscience that howwaves of light work, that how the optical system operates, and that how

we reflect. But she never sees what colors look like except black, whit eand gray. One day she is released out of the Black-While Room. She directly sees red for her first time. What happens to her? Will she learn something new about red? Intuitively, she learns something new about red. As Jackson said, "she will learn what it is like to seeing something red."2

That is thought experiment which attacks physicalism. If you are confused, I will reconstruct the thought experiment so that we can knowit more clearly.

Reconstruction and fault

According to the thought experiment, Frank Jackson's argument can be summarized as the following.

  • [P1] If physicalism is true, then physical facts about red is all the fact about red. (Definition of physicalism)
  • [P2] If Mary knows all physical fact about red, then she will not learn something new about red after she sees what red is like. (Thought experiment: Mary in the black-white room)
  • [P3] Mary know something new about red after she sees what red is like. (P2 + intuition)
  • [C1] Mary does not know all physical facts about red. (P2 and P3 by modus tollens)
  • [C2] Physical facts about red is not all the fact about red. (derived by C1)
  • [C] physicalism is false. (C2 and P1 by modus tollens)

Above summary is argument reconstruction. It is of help to see the detail of thought experiment.

It is noted worthy that some implicit premises hide into the argument. I will try to argue with Frank Jackson by objecting an implicit premise. Iwill refute P2. More precisely, I will refute the proportion that Mary knows all physical fact about red.

Followingly, there is my reason.

First, let's scrutinize the term all physical facts. This term is vague. Because the quantity of physical facts is based on physical development. The degree of physical development determines the known physical facts. But epistemological limitation confines physical development. In otherword, epistemological limitation confines the number of physical facts. Here we can derive that all physical facts are a relative notion. We canalso review physicalism. It is claimed all facts can be reduced tophysical facts. We should notice that all physical facts underphysicalism concept are limited by known physical facts.

Turning to Frank Jackson, we remember P2 that is claimed Mary knows allphysical fact about red. Frank Jackson implicitly implies that all physical facts are completely all and nothing else. I should explain further. The term, completely all and nothing else is meant that Mary has no limited epistemological boundary to acquire physical facts. Mary acquires all physical fact about color without any epistemological limitation. This is contradictory to the claim of physicalism. Maybe anexample can be illustrated more concretely. In the world, even thoughthe top scientists specialize in their field, they do not claim they learn all physical facts about their studies in their fields. Mary asother scientists in the real world should learn all known physical facts. So, Mary does not learn all physical facts which Frank Jackson implies.

While we have the reason that Mary does not have all physical factsabout red. Then P2 is possibly false. Lack of strong and supportive P2leads that what Mary learn something new about red released of the Black-White Room is probably physical. Therefore, the thought experiment cannot disprove physicalism.

Objection from Frank Jackson

Frank Jackson might defend P2 which Mary does know all the physicalfacts about red. In his paper, he claims that "Mary knows all physical facts about us and our environment."3 He might argue that Mary can acquire physical facts through black-white lecture and television.

[Reply] physical facts are in the real world. The top scientists cannot learn all the physical facts in the real world. Mary was confined to the Black-White Room. This environment is separated from the real world. The physical facts in the Black-White Room do not contain all the physical fact in the real world. Mary does not learn all physical facts about red. The physical facts about red she learns are just part of all physical facts in the real world.


Jackson, Frank. "What Mary didn't know." The Journal of Philosophy 83.5 (1986): 291


Ibid. 291


Ibid. 291