# chapter 6 - Logic and Reasoning PHIL 102[10 3 Oct 2011...

This preview shows pages 1–3. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Logic and Reasoning PHIL 102 [10] 3 Oct 2011 Today: CHAPTER 6 Deductive Reasoning: Propositional Logic So far… Arguments = a few sentences put together in order to support a conclusion Sentences = statements = claims = say that something is (or isn’t) the case = can be true or false = have ‘truth-value’ So far… Arguments = a few sentences put together in order to support a conclusion Arguments: good or bad Good = valid + sound Bad = fallacies (various) So far… Arguments = a few sentences put together in order to support a conclusion Arguments: good or bad Good = valid + sound Validity b the conclusion follows from the premises Propositional logic (= truth-functional logic) studies the logical relations between propositions / statements. Simple statements: ‘John sleeps’, ‘John smokes’ Composite statements: ‘John visited his mother and went shopping ’ Propositional logic (= truth-functional logic) studies the logical relations between propositions / statements. Simple statements: ‘John sleeps’, ‘John smokes’ Composite statements: ‘John visited his mother and went shopping ’ One thought / claim More than one thought / claim Propositional logic (= truth-functional logic) studies the logical relations between propositions / statements . Simple statements: ‘John sleeps’, ‘John smokes’ Composite statements: ‘John visited his mother and went shopping ’ Relations of logical, not causal nature Relevant later! Method? b Symbolization 1. Identify simple statements 2. Assign a letters to them If Carter is the president , then the moon is made of green cheese . The moon is not made of green cheese . Therefore Carter is the not the president . Method? b Symbolization 1. Identify simple statements 2. Assign a letters to them If Carter is the president , then the moon is made of green cheese . The moon is not made of green cheese . Therefore Carter is not the president . P = Carter is the president Q = The moon is made of green cheese Method? b Symbolization 1. Identify simple statements 2. Assign a letters to them If Carter is the president , then the moon is made of green cheese . The moon is not made of green cheese . Therefore Carter is not the president . P = Carter is the president Q = The moon is made of green cheese P Not P Q Not Q Method? b Symbolization 1. Identify simple statements 2. Assign a letters to them If Carter is the president , then the moon is made of green cheese . The moon is not made of green cheese . Therefore Carter is not the president . P = Carter is the president Q = The moon is made of green cheese P Not P Q Not Q If P, then Q. Not Q. Therefore, not P. Method? b Symbolization 1. Identify simple statements 2. Assign a letters to them If Carter is the president , then the moon is made of green cheese . The moon is not made of green cheese . Therefore Carter is not the president ....
View Full Document

{[ snackBarMessage ]}

### Page1 / 8

chapter 6 - Logic and Reasoning PHIL 102[10 3 Oct 2011...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online