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Unformatted text preview: Branden Fitelson Philosophy 12A Notes 1 Overview of Todays Lecture Todays Music: Black Roots Richard will have extra office hours from 3:305 today. My office hours are 45:30 on Wednesdays. HW #2 due Friday @ 5pm in the 12A Drop Box (outside 301 Moses). Make sure you follow the guidelines/hints on my HW Tips Handout The midterm is next Thursday (in class). Ill post a sample tomorrow. And, I will discuss the sample exam in lecture next Wednesday. I have posted a handout on the short method for testing LSL validity. I will be going over this handout in lecture very soon. More 12A Practice Problems can be found in: Schaums Outline of Logic Today: Chapter 3, Continued UCB Philosophy Chapter 3 (Contd) 06/02/10 Branden Fitelson Philosophy 12A Notes 2 Abstract Argument Logical Form LSL / LMPL / LFOL Symbolization Chapters 2, 5 & 7 English Argument Valid Form? Deciding Formal Validity Chapters 3 , 4, 6 & 8 Valid English Argument? Valid Abstract Argument? Articulation of Thought in English UCB Philosophy Chapter 3 (Contd) 06/02/10 Branden Fitelson Philosophy 12A Notes 3 p p p q p & q p q p q p q p q p q p q UCB Philosophy Chapter 3 (Contd) 06/02/10 Branden Fitelson Philosophy 12A Notes 4 Chapter 3 Semantics of LSL: Truth Functions VII If our truthfunctional semantics for doesnt perfectly capture the English meaning of if . . . then . . . , then why do we define it this way? The answer has two parts. First, our semantics is truthfunctional . This is an idealization it yields the simplest (Newtonian) semantics. And, there are only 2 4 = 16 possible binary truthfunctions. Why? So, unless one of the other 15 binary truthfunctions is closer to the English conditional than is, its the best we can do , truthfunctionally . More importantly, there are certain logical properties that the conditional must have. It can be shown that our definition of is the only binary truthfunction which satisfies all three of the following: (1) Modus Ponens [ p and [ p q q ] is a valid sentential form. (2) Affirming the consequent [ q and [ p q p ] is not a valid form. (3) All sentences of the form [ p p are logical truths. UCB Philosophy Chapter 3 (Contd) 06/02/10 Branden Fitelson Philosophy 12A Notes 5 Chapter 3 Semantics of LSL: Truth Functions VIII Here are all of the 16 possible binary truthfunctions. Ive given them all names or descriptions. [Only a few of these names were made up by me.] p q nand p fi ( ) q nor niff q nfi p nif &...
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 Fall '06
 Buechner
 Philosophy

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