EPM: Ch II Pete Mandik Chairman, Department of Philosophy Coordinator, Cognitive Science Laboratory William Paterson University, New Jersey USA

2 Some Background: Mental States that are propositional attitudes vs. mental states that are not Examples of propositional attitudes: n Believing that the grass is green n Desiring that you win the lotto n Knowing that two and two are four Examples of mental states that are not propositional attitudes: n Feeling sad n Fearing spiders n Having a tingly sensation ONLY PROPOSITIONAL ATTITUDES CAN BE REASONS OR JUSTIFY KNOWLEDGE CLAIMS

3 So maybe… sense datum talk (which isn’t obviously about propositional attitudes) is really code for appearance talk (which is about propositional attitudes).

4 The idea of a code Symbols that (by stipulation) stand for sentences, even though the symbol parts (also by stipulation) don’t stand for anything Symbol:  Stands for: All puppies are mammals Symbol:  Stands for: Some mammals are puppies Symbol:  Stands for: All mammals are puppies

5 Question: Does  entail  ?

6 Answer: NO! 1.  means nothing other than “all puppies are mammals” 2.  means nothing other than “all mammals are puppies” 3. “all puppies are mammals” does not entail “all mammals are puppies” Therefore:  does not entail 

7 Another example Symbol: There is a rock in my shoe Stands for: The party is at the bar Symbol: Something made of minerals is in my shoe Stands for: You are invited to the party

8 Question Does “There is a rock in my shoe” entail “something made of minerals is in my shoe”?

9 Answer: NO! 1. “There is a rock in my shoe” means nothing other than “The party is at the bar” 2. “Something made of minerals is in my shoe” means nothing other than “you are invited to the party” 3. “The party is at the bar” does not entail “you are invited to the party Therefore: “There is a rock in my shoe” does not entail “something made of minerals is in my shoe”

10 Sense data talk as code for appearance (e.g. ‘looks’) talk Symbol: I have a red sense datum Stands for: Something looks red to me Symbol: I have a sense datum that is a determinate shade of red Stands for: Something looks a determinate shade of red to me

11 Question Does “I have a red sense datum” entail “I have a sense datum that is a determinate shade of red”?

12 Answer NO! 1. “I have a red sense datum” means nothing other than “something looks red to me” 2. “I have a sense datum that is a determinate shade of red” means nothing other than “Something looks a determinate shade of red to me” 3. “something looks red to me” does not entail “something looks a determinate shade of red to me” Therefore: “I have a red sense datum” does not entail “I have a sense datum that is a determinate shade of red”

13 Another example Symbol: “A plant has chlorophyll in it” Stands for: “A plant photosynthesizes” Question: Does “a plant has chlorophyll in it” explain “a plant photosynthesizes”?

14 Answer NO! If P is just a code for Q, then P cannot explain Q (because Q cannot explain Q) “a plant photosynthesizes because a plant photosynthesizes” is no explanation at all If “a plant has chlorophyll in it” does explain “a plant photosynthesizes” then “a plant has chlorophyll in it” cannot be merely a code for “a plant has chlorophyll in it”.

15 Analogously… If sense data talk is merely code for appearance talk then sense data cannot constitute explanations of appearances

16 Another thing Logical Positivists want to define all physical objects and other people as logical constructions of sense data If sense data talk is merely a code for the way things look or appear, then for the Logical Positivists to succeed they must be able to define all physical objects and other people as logical constructions of the way objects and people look or appear

17 In other words… According to the Logical Positivists the way things are can be constructed out of (and thus must be conceptually posterior to) the way things seem. According to Sellars, as he will argue in the next chapter, the way things are cannot be constructed out of the way things seem because the way things are is conceptually prior to the way things seem

18 THE END