Preliminary For our purposes Physicalism Materialism Jackson is

Preliminary For our purposes, Physicalism = Materialism. Jackson is a “qualia freak”; he believes qualia are non-physical.

Mary and The Knowledge Argument Mary learns something new when she finally sees colored things. n But prior to that time, Mary knew all of the physical facts about color experience. n Therefore, what she learns when she finally sees color isn’t a physical fact. n Therefore, there are nonphysical facts. n Therefore, physicalism is false. n

What will the physicalist say? Here’s one possibility: n Seeing red is a certain physical state, R 1. n Knowing what it is like to see red is a certain physical state that typically results from R 1—call this R 2. n Knowing all about the physical process involved in color vision involves a bunch of other states R 3. . . Rn. Why should we expect that being in R 3. . Rn would cause R 1 or R 2?

The Knowledge argument restated? Mary was in R 3. . . Rn (but not R 1 or R 2) which represent, among other things, facts about R 1 and R 2. n Then Mary went outside and was in R 2, caused by her being in R 1. n So. . . ? Why should physical states whose contents are facts about R 1 or R 2 have any special power to cause physical state R 2? n

Diagnosis Jackson’s reasoning was airtight, though. Where does he go wrong in his assumptions? Jackson has a choice: 1. He can say that knowing all of the physical facts about color includes being in states R 1 and R 2 In which case Mary doesn’t know everything physical about color vision when in the room, and he has mis-described the example.

Or 2. Jackson can say that Mary, as he described here, knew everything physical to know about vision, explicitly excluding being in R 1 and R 2 from the original description; in which case, Mary’s “learning something new” (that is, her brain going into R 1, then R 2) doesn’t count against physicalism. On this interpretation, Jackson has constrained the set of physical facts, excluding certain states of the brain that are caused by interacting with colored things.

But what does Mary learn!? Possibility: She learns new facts about physical events in her own biography: “I was in R 1” (which is partly expressed by the activation of R 2). This is the content of R 2. Obviously, it cannot be induced merely by knowing the facts about color vision, even if it is physical.

Physicalism and what it’s like to be a bat A human cannot know what it is like to echolocate. Humans can know all of the physical facts about echolocation. So, the physical facts leave something out. So, physicalism is false. Similar diagnosis to Mary’s case

The modal argument and zombies It is possible for there to exist a perfect physical duplicate of an actual human being that lacks conscious experience. Therefore, physicalism is false (the actual person must have a nonphysical aspect that’s being “left out”).