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Unformatted text preview: 1 Monday, July 09, 2007 10:07 AM Instructor Alex Morgan What is logic? Logic is the study of making 'good' or 'correct' reasoning. Making good inferences e.g. see smoke, infer fire. We'll focus on a type of inference called an argument. Argument is a collection of Premises that support a conclusion. A statement is a declarative sentence. Declarative "the window is shut". Interrogative "Is the window shut?" Imperative "Shut the window!" A proposition is the substance of a sentence. The conclusion should follow from the premises. I. If there is smoke, there is fire (premise 1) II. There is smoke III. Therefore there is fire I. If there is smoke, there is fire II. There is smoke A valid argument means that assuming the premises are true the conclusion must be true. In essence, the form of the argument is correct. An argument is factually correct if the premises and conclusion are true. An argument that is valid and has true premises is called sound. All X are Y All Y are Z All X are Z All X are Y All Z are Y All X are Z Intro to Logic Page 1 A deductive argument is one where the truth of the premises are supposed to logically guarantee a conclusion. Inductive logic is where the premises make the conclusion more likely. Deductive logic was studied in Ancient Greece, India, and China. In the western system Aristotle's system of logic became widespread. Aristotle's system was based on syllogisms. A syllogism has two premises and a conclusion. The statements contain descriptive terms which refer to sets of things and logical terms such as all or some. When we look at the form we change the descriptive terms and hold the logical terms constant. Some x are y All y are z Therefore all x are z Around the 1800's a German logician named Gottlob Frege tried to develop formal logic. Intro to Logic Page 2 ...
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This note was uploaded on 04/07/2008 for the course PHILOSOPHY 201 taught by Professor Morgan during the Spring '08 term at Rutgers.
 Spring '08
 Morgan

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