Propositions and Arguments. What is a proposition? A proposition is a predicative sentence that only contains a subject and a predicate S is P.

Slides:

Advertisements

Similar presentations

-- in other words, logic is

Advertisements

Basic Terms in Logic Michael Jhon M. Tamayao.

Formal Criteria for Evaluating Arguments

Types of Arguments Inductive Argument: An argument in which the truth of the premises is supposed to prove that the conclusion is probably true. Strong.

Deductive Arguments: Categorical Logic

Higher / Int.2 Philosophy 5. ” All are lunatics, but he who can analyze his delusion is called a philosopher.” Ambrose Bierce “ Those who lack the courage.

Classifying Arguments Deductive (valid/invalid) Inductive (strong/weak) Arguments may be divided into two types: in which the intention is certainty of.

Analysis of Diagnostic Essay: The Deductive Argument English 102 Argumentation.

Intro to Logic: the tools of the trade You need to be able to: Recognize an argument when you see one (in media, articles, people’s claims). Organize arguments.

Reasoning Automated Deduction. Reasonable Arguments Argument: An attempt to demonstrate the truth of a conclusion from the truth of a set of premises.

Me Talk Good One Day When Language and Logic Fail to Coincide.

1 Chapter 7 Propositional and Predicate Logic. 2 Chapter 7 Contents (1) l What is Logic? l Logical Operators l Translating between English and Logic l.

Logic. what is an argument? People argue all the time ― that is, they have arguments.  It is not often, however, that in the course of having an argument.

For Friday, read chapter 2, sections 1-2 (pp ). As nongraded homework, do the problems on p. 19. Graded homework #1 is due at the beginning of class.

Essential Deduction Techniques of Constructing Formal Expressions Evaluating Attempts to Create Valid Arguments.

BASIC CONCEPTS OF ARGUMENTS

Inductive and Deductive Reasoning Geometry 1.0 – Students demonstrate understanding by identifying and giving examples of inductive and deductive reasoning.

DEDUCTIVE & INDUCTIVE ARGUMENTS

Basic Argumentation.

Copyright © 2008 Pearson Education, Inc. Chapter 1.

Validity All UH students are communists. All communists like broccoli. All UH students like broccoli.

GLE Explore the concept of premises, including false premises. Intro to Logic.

Logic and Philosophy Alan Hausman PART ONE Sentential Logic Sentential Logic.

1 Chapter 7 Propositional and Predicate Logic. 2 Chapter 7 Contents (1) l What is Logic? l Logical Operators l Translating between English and Logic l.

Deductive versus Inductive Reasoning Consider the following two passages: Argument #1 Mr. Jones is a member of the Academy of Scholarly Fellows and only.

1 Knowledge Representation. 2 Definitions Knowledge Base Knowledge Base A set of representations of facts about the world. A set of representations of.

The Science of Good Reasons

Reasoning and Critical Thinking Validity and Soundness 1.

Question of the Day!  We shared a lot of examples of illogical arguments!  But how do you make a LOGICAL argument? What does your argument need? What.

DEDUCTIVE REASONING MOVES FROM A GENERALIZATION THAT IS TRUE OR SELF-EVIDENT TO A MORE SPECIFIC CONCLUSION DEDUCTIVE REASONING.

Proof and Probability (can be applied to arguments for the existence of God)

2.8 Methods of Proof PHIL 012 1/26/2001.

Theory of Knowledge Ms. Bauer

LOGICAL REASONING FOR CAT 2009.

Philosophy: Logic and Logical arguments

Today’s Topics Introduction to Proofs Rules of Inference Rules of Equivalence.

Philosophical Method  Logic: A Calculus For Good Reason  Clarification, Not Obfuscation  Distinctions and Disambiguation  Examples and Counterexamples.

The construction of a formal argument

Sentence (syntactically Independent grammatical unit) QuestionCommandStatement “This is a class in logic.” “I enjoy logic.” “Today is Friday.”

Section 2.3: Deductive Reasoning

Class 1 (Sept.6): “First steps …”.  You all are philosophers. You all are theologians.  Your Philosophy Should Evolve.  You are not required to have.

Higher / Int.2 Philosophy 12. Our Learning  Fallacy Reminder  Summary following Homework NAB  Class NAB.

© 2009 McGraw-Hill Higher Education. All rights reserved.1 Chapters1 & 2.

Section 3.6 Reasoning and Patterns. Deductive Reasoning Deductive reasoning starts with a general rule, which we know to be true. Then from that rule,

CT214 – Logical Foundations of Computing Darren Doherty Rm. 311 Dept. of Information Technology NUI Galway

Chapter III Evaluating Arguments. Nondeductive Arguments Most common kinds of arguments Successful arguments are a matter of degree. Deal with likelihood.

Deductive Reasoning. Inductive: premise offers support and evidenceInductive: premise offers support and evidence Deductive: premises offers proof that.

Types of Arguments Inductive Argument: An argument in which the truth of the premises is supposed to prove that the conclusion is probably true. Strong.

Deductive vs. Inductive Arguments

Deductive reasoning.

Chapter 3 Basic Logical Concepts (Please read book.)

a valid argument with true premises.

Logic & Reasoning.

Inductive / Deductive reasoning

Introduction to Logic PHIL 240 Sections

Validity and Soundness

Reasoning, Logic, and Position Statements

Testing for Validity and Invalidity

Inductive and Deductive Logic

Thinking Critically Copyright © 2011 Pearson Education, Inc.

Validity & Invalidity Valid arguments guarantee true conclusions but only when all of their premises are true Invalid arguments do not guarantee true conclusions.

6.4 Truth Tables for Arguments

Logical Fallacies.

SUMMARY Logic and Reasoning.

Propositional Logic 1) Introduction Copyright 2008, Scott Gray.

Evaluating Deductive Arguments

If there is any case in which true premises lead to a false conclusion, the argument is invalid. Therefore this argument is INVALID.

Validity and Soundness, Again

If there is any case in which true premises lead to a false conclusion, the argument is invalid. Therefore this argument is INVALID.

Presentation transcript:

Propositions and Arguments

What is a proposition? A proposition is a predicative sentence that only contains a subject and a predicate S is P.

Which of these sentences express propositions? 1.Sydney is north of Melbourne. 2.Is Edinburgh in Scotland? 3.The moon is made of swiss cheese. 4.Did you see the eclipse? 5.What an eclipse! 6.Would that I were good at logic. 7.Look at the eclipse. 8.I wish that I were good at logic =23

Arguments Arguments in everyday situations take place between people. Arguments give reasons for believing the truth of a proposition. Logic studies the information content of these arguments.

An argument is a list of propositions, called the premises, followed by a word such as ‘therefore’, or ‘so’, and then another proposition, called the conclusion. The reason for accepting the information in the conclusion is based on the premises. If everything is determined, people are not free. Premise People are free. Premise So not everything is determined. Conclusion

Rule Individual instances Rule Individual instances INDUCTIVE Arguments DEDUCTIVE Arguments

Rule Individual instances INDUCTIVE Arguments Most Hungarians commit tax fraud. Gábor is Hungarian. So, Gábor is likely to commit tax fraud. The link between the premises weaker. The truth of the premises only makes the truth of the conclusion, but does not guarantee it The conclusion is only possibly true. These arguments are Inductive arguments.

Rule Individual instances DEDUCTIVE Arguments All Hungarians commit tax fraud. Gábor is Hungarian. So, Gábor commits tax fraud. The premises support the truth of the conclusion: it is impossible for the premises to be true and the conclusion to be false. These are called deductive arguments. People commiting tax fraud Hungarians

Valid arguments An argument is valid if and only if whenever the premises are true, so is the conclusion. In other words, it is impossible for the premises to be true while at the same time the conclusion is false.

Sound arguments An argument is sound, just in the case where it is valid, and, in addition, the premises are all true. So, the conclusion of a sound argument must also be true. soundness appeals to the truth of the matter.

Valid Argument Scheme All bats are birds. H All birds fly. HNot sound Therefore all bats fly. I All whales are mammals.I All mammals have hearts. I Sound All whales have hearts. I c A B C All A’s are B’s All B’s are C’s So all A’s are C’s