# Introduction to Logic

Size: px
Start display at page:

Transcription

1 University of Notre Dame Fall, 2015

2 Arguments Philosophy is difficult. If questions are easy to decide, they usually don t end up in philosophy The easiest way to proceed on difficult questions is to formulate and evaluate various arguments Logic is the the study of arguments An argument is a set of sentences, one of which is trying to be proven. The setnence to be proven is called the conclusion The claims in an argument which are not the conclusion are called premises

3 Good and Bad Arguments Once you have a set of a set of sentences in which premises try to establish a conclusion, you have an argument. Then what? In philosophy, we are not just concerned with arguments, but with good arguments. What makes an argument good or bad? Consider the following: (1) Notre Dame is in Indiana (2) Indiana is in the midwest (C) Notre Dame is good at football.

4 (1) Notre Dame is in Indiana (2) Indiana is in the midwest (C) Notre Dame is good at football. Why is this a bad argument? (1) is true. (2) is true. (C) is true...usually. So what is the problem? The issue is not with one of the statements, but with how the argument moves from the premises to the conclusion. The premises have nothing to do with whether or not the conclusion is true. Some years, sadly, both premises are true and the conclusion is false. If an argument is such that all its premises could be true and its conclusion false we call it invalid. Conversely, if it is impossible for all the premises of an argument to be true and the conclusion false (i.e. the premises guarantee the conclusion) we call it valid.

5 to be true and the conclusion false. (1) Tom Brady plays for the Patriots. (2) The Patriots are all cheaters. (C) Tom Brady is a cheater. Valid (1) Russell Wilson doesn t play for the Patriots. (2) The Patriots are all cheaters. (C) Russell Wilson isn t a cheater. Invalid

6 to be true and the conclusion false. (1) If Frodo destroys the ring Sauron will die. (2) Sauron died. (C) Frodo destroyed the ring. Invalid (1) If Harry blows up the Death Star, Sauron will die. (2) Harry blew up the Death Star. (C) Sauron died. Valid

7 Other Evaluations to be true and the conclusion false. Logic is concerned entirely with the reasoning of arguments. This means logicians only evaluate validity and invalidity. As philosophers, there are more ways we can evaluate arguments, but we should always start with evaluating validity. One other thing we are concerned with is whether or not the premises are true. However, it does us no good to merely know the truth of the premises and conclusion. Consider: (1) The sun is bigger than the moon.true (2) Milk comes from cows. True (C) Tigers are carnivorous. True Is this argument helpful in any way? Why not? Arguments are supposed to move Introduction you to from Logic things you know

8 Soundness to be true and the conclusion false. We only care about the truth of the premises if we already know that the argument is valid. If an argument is valid and its premises are true, then we call the argument sound. Notice that a sound argument will always have a true conclusion. This is precisely why sound arguments are useful.

9 to be true and the conclusion false. An argument is sound if and only if it is valid and the premises are true. (1) Tom Brady plays for the Patriots. True (2) The Patriots are all cheaters. False (C) Tom Brady is a cheater. Valid Unsound (1) Russell Wilson doesn t play for the Patriots. (2) The Patriots are all cheaters. (C) Russell Wilson isn t a cheater. Invalid Unsound

10 to be true and the conclusion false. An argument is sound if and only if it is valid and the premises are true. (1) Everett Golson plays for Florida State. True (2) No Florida State player plays for Notre Dame. True (C) Everett Golson does not play for Notre Dame. True Valid Sound (1) Notre Dame plays Georgia Tech this year. True (2) Georgia Tech is in the Big 12. False (C) Notre Dame plays a team in the Big 12 this year. Valid True Unsound

11 to Anbe argument true andisthe sound conclusion if and only false. if it is valid and the premises are true. There are many other ways one could evaluate an argument. The last one we will look at is a bit subjective, but still can be important for certain purposes. Consider the following argument: (1) If atheists belief that there is no God is true, then there is no God. True (2) Atheists belief that there is no God is true. Maybe (C) There is no God. Valid Sound? Suppose this is a sound argument; is it then a good argument? Why might someone be unsatisfied with it? Let us call an argument informative if and only if the premises are more plausible than the conclusion.

12 to be true and the conclusion false. An argument is sound if and only if it is valid and the premises are true. An argument is informative if and only if its premises are more plausible than its conclusion. Evaluate the following for validity, soundness, and informativeness. If it is invalid, show that it is invalid: (1) All men are mortal. (2) Socrates is a man. (C) Socrates is mortal. Valid Sound Informative

13 to be true and the conclusion false. An argument is sound if and only if it is valid and the premises are true. An argument is informative if and only if its premises are more plausible than its conclusion. Evaluate the following for validity, soundness, and informativeness. If it is invalid, show that it is invalid: (1) Everyone who shows up to class gets an A. (2) Johnny got an A. (C) Johnny showed up to class. Invalid Unsound

14 to be true and the conclusion false. An argument is sound if and only if it is valid and the premises are true. An argument is informative if and only if its premises are more plausible than its conclusion. Evaluate the following for validity, soundness, and informativeness. If it is invalid, show that it is invalid: (1) Some Students have false beliefs. (2) I am a student who has false beliefs. (C) I have false beliefs. Valid Sound Uninformative

15 to be true and the conclusion false. An argument is sound if and only if it is valid and the premises are true. An argument is informative if and only if its premises are more plausible than its conclusion. Evaluate the following for validity, soundness, and informativeness. If it is invalid, show that it is invalid: (1) Snow is white. (2) Snow is cold. (C) Today is Tuesday. Invalid

16 to be true and the conclusion false. An argument is sound if and only if it is valid and the premises are true. An argument is informative if and only if its premises are more plausible than its conclusion. Evaluate the following for validity, soundness, and informativeness. If it is invalid, show that it is invalid: (1) All men are mortal. (C) All men are mortal. Valid Sound Uninformative

17 to be true and the conclusion false. An argument is sound if and only if it is valid and the premises are true. An argument is informative if and only if its premises are more plausible than its conclusion. Evaluate the following for validity, soundness, and informativeness. If it is invalid, show that it is invalid: (1) All gingers have souls. (2) Some students are not gingers. (C) Some students do not have souls. Invalid

18 to be true and the conclusion false. An argument is sound if and only if it is valid and the premises are true. An argument is informative if and only if its premises are more plausible than its conclusion. Evaluate the following for validity, soundness, and informativeness. If it is invalid, show that it is invalid: (1) No one should judge someone who is a part of a different culture. (2) None of us was a part of Nazi culture. (C) None of us should judge the Nazis. Valid Unsound

19 to be true and the conclusion false. An argument is sound if and only if it is valid and the premises are true. An argument is informative if and only if its premises are more plausible than its conclusion. Evaluate the following for validity, soundness, and informativeness. If it is invalid, show that it is invalid: (1) If a student plagiarizes a paper, they will get a 0 on that paper. (2) Last semester a student plagiarized a paper. (C) Last semester a student got a 0 on a paper. Valid Sound Informative

20 Important Arguments Certain types of argument recur often enough that they deserve special attention. The ones we will focus on for this class are those involving if-then statements. If-then statements occur often in philosophy both because they can be used to express causal or other connections, and because they are connected with/can be supplied by necessary and sufficient conditions, which we have seen can be used to analyze concepts. If P then Q = P is sufficient for Q = P Q P only if Q (If Q then P) = P is necessary for Q = P Q P iff Q = P is necessary and sufficient for Q = P Q

21 The 4 forms Antecedent Consequent There are 4 and only 4 ways one can argue using an if-then statement Affirm (1) If P then Q (2) P (C) Q Modus Ponens (1) If P then Q (2) Q (C) P Affirming the Consequent Deny (1) If P then Q (2) Not P (C) Not Q Denying the Antecedent (1) If P then Q (2) Not Q (C) Not P Modus Tollens

22 Is the following argument Modus Ponens, Modus Tollens, Affirming the Consequent, or Denying the Antecedent? Is it valid? (1) If Notre Dame goes undefeated, they will win the playoffs. (2) Notre Dame will go undefeated. (C) Notre Dame will win the playoffs. Modus Ponens (1) If it rains, the sidewalks will be wet. (2) It did not rain. (C) The sidewalks are not wet. Denying the Antecedent

23 Is the following argument Modus Ponens, Modus Tollens, Affirming the Consequent, or Denying the Antecedent? Is it valid? (1) If a student goes to Notre Dame, then they are Catholic. (2) Pope Francis does not go to Notre Dame. (C) Pope Francis is not Catholic. Denying the Antecedent (1) If the government tracks where you are, they are invading your privacy. (2) The government is invading your privacy. (C) The government tracks where you are. Affirming the Consequent

24 Is the following argument Modus Ponens, Modus Tollens, Affirming the Consequent, or Denying the Antecedent? Is it valid? (1) If something is a table, then it has a flat surface. (2) The chair does not have a flat surface. (C) The chair is not a table. Modus Tollens (1) If this argument is not Modus Ponens, then it is Modus Tollens. (2) This argument is not Modus Tollens. (C) This argument is Modus Ponens. Modus Tollens

25 Formalization Outside of a philosophy classroom you will rarely encounter arguments in explicit premise-conclusion form. Instead, you are much more likely to come across them as paragraphs following no rigorous structure. So why do philosophers bother to state them in this way? CLARITY! when arguments are stated in premise-conclusion form it is much easier to evaluate whether or not they are valid. Furthermore, if an argument is valid but rests on a false assumption, it is much easier to point out the false assumption if one can point to an explicit premise which is false.

26 Formalizing When turning paragraphs into explicit arguments there are a few things to keep in mind: Figure out what is actually being argued the conclusion isn t always the last sentence of the paragraph Eliminate unnecessary information Paragraphs will often include other information not relevant to the argument at hand Simplify the premises as much as possible Try to make arguments valid; be as charitable as possible when interpreting people. If there is an assumption that is needed to make an argument valid fill it in, but mark it as something you added.

27 Turn the following argument into explicit premise-conclusion form: Every person has a right to life. So the fetus has a right to life. Not doubt the mother has a right to decide what shall happen in and to her body; everyone would grant that. But surely a person s right to life is stronger and more stringent than the mother s right to decide what happens in and to her body, and so outweighs it. So the fetus may not be killed; an abortion may not be performed.

28 Turn the following argument into explicit premise-conclusion form: The development of a human being from conception through birth into childhood is continuous; to draw a line, to choose a point in this development and say before this point the thing is not a person, after this point it is a person is to make an arbitrary choice, a choice for which in the nature of things no good reason can be given. Therefore, the fetus is, or should be treated like, a person from the moment of conception.

### Introduction to Logic

University of Notre Dame Spring, 2017 Arguments Philosophy has two main methods for trying to answer questions: analysis and arguments Logic is the the study of arguments An argument is a set of sentences,

### Philosophy 1100: Ethics

Philosophy 1100: Ethics Topic 1 - Course Introduction: 1. What is Philosophy? 2. What is Ethics? 3. Logic a. Truth b. Arguments c. Validity d. Soundness What is Philosophy? The Three Fundamental Questions

### Lecture 3 Arguments Jim Pryor What is an Argument? Jim Pryor Vocabulary Describing Arguments

Lecture 3 Arguments Jim Pryor What is an Argument? Jim Pryor Vocabulary Describing Arguments 1 Agenda 1. What is an Argument? 2. Evaluating Arguments 3. Validity 4. Soundness 5. Persuasive Arguments 6.

### PHI 1500: Major Issues in Philosophy

PHI 1500: Major Issues in Philosophy Session 3 September 9 th, 2015 All About Arguments (Part II) 1 A common theme linking many fallacies is that they make unwarranted assumptions. An assumption is a claim

### Criticizing Arguments

Kareem Khalifa Criticizing Arguments 1 Criticizing Arguments Kareem Khalifa Department of Philosophy Middlebury College Written August, 2012 Table of Contents Introduction... 1 Step 1: Initial Evaluation

### Selections from Aristotle s Prior Analytics 41a21 41b5

Lesson Seventeen The Conditional Syllogism Selections from Aristotle s Prior Analytics 41a21 41b5 It is clear then that the ostensive syllogisms are effected by means of the aforesaid figures; these considerations

### Philosophy 1100: Introduction to Ethics. Critical Thinking Lecture 1. Background Material for the Exercise on Validity

Philosophy 1100: Introduction to Ethics Critical Thinking Lecture 1 Background Material for the Exercise on Validity Reasons, Arguments, and the Concept of Validity 1. The Concept of Validity Consider

### Overview of Today s Lecture

Branden Fitelson Philosophy 12A Notes 1 Overview of Today s Lecture Music: Robin Trower, Daydream (King Biscuit Flower Hour concert, 1977) Administrative Stuff (lots of it) Course Website/Syllabus [i.e.,

### Lecture 1: Validity & Soundness

Lecture 1: Validity & Soundness 1 Goals Today Introduce one of our central topics: validity and soundness, and its connection to one of our primary course goals, namely: learning how to evaluate arguments

### PHILOSOPHY 102 INTRODUCTION TO LOGIC PRACTICE EXAM 1. W# Section (10 or 11) 4. T F The statements that compose a disjunction are called conjuncts.

PHILOSOPHY 102 INTRODUCTION TO LOGIC PRACTICE EXAM 1 W# Section (10 or 11) 1. True or False (5 points) Directions: Circle the letter next to the best answer. 1. T F All true statements are valid. 2. T

### Chapter 1. What is Philosophy? Thinking Philosophically About Life

Chapter 1 What is Philosophy? Thinking Philosophically About Life Why Study Philosophy? Defining Philosophy Studying philosophy in a serious and reflective way will change you as a person Philosophy Is

### Relevance. Premises are relevant to the conclusion when the truth of the premises provide some evidence that the conclusion is true

Relevance Premises are relevant to the conclusion when the truth of the premises provide some evidence that the conclusion is true Premises are irrelevant when they do not 1 Non Sequitur Latin for it does

### Argumentation Module: Philosophy Lesson 7 What do we mean by argument? (Two meanings for the word.) A quarrel or a dispute, expressing a difference

1 2 3 4 5 6 Argumentation Module: Philosophy Lesson 7 What do we mean by argument? (Two meanings for the word.) A quarrel or a dispute, expressing a difference of opinion. Often heated. A statement of

### Mr Vibrating: Yes I did. Man: You didn t Mr Vibrating: I did! Man: You didn t! Mr Vibrating: I m telling you I did! Man: You did not!!

Arguments Man: Ah. I d like to have an argument, please. Receptionist: Certainly sir. Have you been here before? Man: No, I haven t, this is my first time. Receptionist: I see. Well, do you want to have

### 4.1 A problem with semantic demonstrations of validity

4. Proofs 4.1 A problem with semantic demonstrations of validity Given that we can test an argument for validity, it might seem that we have a fully developed system to study arguments. However, there

### Logic Book Part 1! by Skylar Ruloff!

Logic Book Part 1 by Skylar Ruloff Contents Introduction 3 I Validity and Soundness 4 II Argument Forms 10 III Counterexamples and Categorical Statements 15 IV Strength and Cogency 21 2 Introduction This

### HOW TO ANALYZE AN ARGUMENT

What does it mean to provide an argument for a statement? To provide an argument for a statement is an activity we carry out both in our everyday lives and within the sciences. We provide arguments for

### Tutorial A03: Patterns of Valid Arguments By: Jonathan Chan

A03.1 Introduction Tutorial A03: Patterns of Valid Arguments By: With valid arguments, it is impossible to have a false conclusion if the premises are all true. Obviously valid arguments play a very important

### A short introduction to formal logic

A short introduction to formal logic Dan Hicks v0.3.2, July 20, 2012 Thanks to Tim Pawl and my Fall 2011 Intro to Philosophy students for feedback on earlier versions. My approach to teaching logic has

### Chapter 3: More Deductive Reasoning (Symbolic Logic)

Chapter 3: More Deductive Reasoning (Symbolic Logic) There's no easy way to say this, the material you're about to learn in this chapter can be pretty hard for some students. Other students, on the other

### Skim the Article to Find its Conclusion and Get a Sense of its Structure

Pryor, Jim. (2006) Guidelines on Reading Philosophy, What is An Argument?, Vocabulary Describing Arguments. Published at http://www.jimpryor.net/teaching/guidelines/reading.html, and http://www.jimpryor.net/teaching/vocab/index.html

### Recall. Validity: If the premises are true the conclusion must be true. Soundness. Valid; and. Premises are true

Recall Validity: If the premises are true the conclusion must be true Soundness Valid; and Premises are true Validity In order to determine if an argument is valid, we must evaluate all of the sets of

### The cosmological argument (continued)

The cosmological argument (continued) Remember that last time we arrived at the following interpretation of Aquinas second way: Aquinas 2nd way 1. At least one thing has been caused to come into existence.

### HANDBOOK (New or substantially modified material appears in boxes.)

1 HANDBOOK (New or substantially modified material appears in boxes.) I. ARGUMENT RECOGNITION Important Concepts An argument is a unit of reasoning that attempts to prove that a certain idea is true by

### A Primer on Logic Part 1: Preliminaries and Vocabulary. Jason Zarri. 1. An Easy \$10.00? a 3 c 2. (i) (ii) (iii) (iv)

A Primer on Logic Part 1: Preliminaries and Vocabulary Jason Zarri 1. An Easy \$10.00? Suppose someone were to bet you \$10.00 that you would fail a seemingly simple test of your reasoning skills. Feeling

### Lecture 2.1 INTRO TO LOGIC/ ARGUMENTS. Recognize an argument when you see one (in media, articles, people s claims).

TOPIC: You need to be able to: Lecture 2.1 INTRO TO LOGIC/ ARGUMENTS. Recognize an argument when you see one (in media, articles, people s claims). Organize arguments that we read into a proper argument

### PHILOSOPHER S TOOL KIT 1. ARGUMENTS PROFESSOR JULIE YOO 1.1 DEDUCTIVE VS INDUCTIVE ARGUMENTS

PHILOSOPHER S TOOL KIT PROFESSOR JULIE YOO 1. Arguments 1.1 Deductive vs Induction Arguments 1.2 Common Deductive Argument Forms 1.3 Common Inductive Argument Forms 1.4 Deduction: Validity and Soundness

### To better understand VALIDITY, we now turn to the topic of logical form.

LOGIC GUIDE 2 To better understand VALIDITY, we now turn to the topic of logical form. LOGICAL FORM The logical form of a statement or argument is the skeleton, or structure. If you retain only the words

### Handout 1: Arguments -- the basics because, since, given that, for because Given that Since for Because

Handout 1: Arguments -- the basics It is useful to think of an argument as a list of sentences.[1] The last sentence is the conclusion, and the other sentences are the premises. Thus: (1) No professors

### Introduction to Analyzing and Evaluating Arguments

Introduction to Analyzing and Evaluating Arguments 1. HOW TO ANALYZE AN ARGUMENT Example 1. Socrates must be mortal. After all, all humans are mortal, and Socrates is a human. What does the author of this

### Introduction to Philosophy

Introduction to Philosophy Philosophy 110W Russell Marcus Hamilton College, Fall 2013 Class 1 - Introduction to Introduction to Philosophy My name is Russell. My office is 202 College Hill Road, Room 210.

### Philosophy Introduction to Philosophy Jeff Speaks What is philosophy?

Philosophy 10100 Introduction to Philosophy Jeff Speaks jspeaks@nd.edu What is philosophy? What is philosophy? Philosophy comes from the ancient Greek φιλοσοφία philosophia. philosophia = philo + sophia

### MCQ IN TRADITIONAL LOGIC. 1. Logic is the science of A) Thought. B) Beauty. C) Mind. D) Goodness

MCQ IN TRADITIONAL LOGIC FOR PRIVATE REGISTRATION TO BA PHILOSOPHY PROGRAMME 1. Logic is the science of-----------. A) Thought B) Beauty C) Mind D) Goodness 2. Aesthetics is the science of ------------.

### Exercise Sets. KS Philosophical Logic: Modality, Conditionals Vagueness. Dirk Kindermann University of Graz July 2014

Exercise Sets KS Philosophical Logic: Modality, Conditionals Vagueness Dirk Kindermann University of Graz July 2014 1 Exercise Set 1 Propositional and Predicate Logic 1. Use Definition 1.1 (Handout I Propositional

### L4: Reasoning. Dani Navarro

L4: Reasoning Dani Navarro Deductive reasoning Inductive reasoning Informal reasoning WE talk of man* being the rational animal; and the traditional intellectualist philosophy has always made a great point

### Basic Concepts and Skills!

Basic Concepts and Skills! Critical Thinking tests rationales,! i.e., reasons connected to conclusions by justifying or explaining principles! Why do CT?! Answer: Opinions without logical or evidential

### Chapter 2 Analyzing Arguments

Logic: A Brief Introduction Ronald L. Hall, Stetson University Chapter 2 Analyzing Arguments 2.1 Introduction Now that we have gotten our "mental muscles" warmed up, let's see how well we can put our newly

### Introducing Our New Faculty

Dr. Isidoro Talavera Franklin University, Philosophy Ph.D. in Philosophy - Vanderbilt University M.A. in Philosophy - Vanderbilt University M.A. in Philosophy - University of Missouri M.S.E. in Math Education

### Pastor-teacher Don Hargrove Faith Bible Church September 8, 2011

Pastor-teacher Don Hargrove Faith Bible Church http://www.fbcweb.org/doctrines.html September 8, 2011 Building Mental Muscle & Growing the Mind through Logic Exercises: Lesson 4a The Three Acts of the

### There are two common forms of deductively valid conditional argument: modus ponens and modus tollens.

INTRODUCTION TO LOGICAL THINKING Lecture 6: Two types of argument and their role in science: Deduction and induction 1. Deductive arguments Arguments that claim to provide logically conclusive grounds

### Full file at

Chapter 1 What is Philosophy? Summary Chapter 1 introduces students to main issues and branches of philosophy. The chapter begins with a basic definition of philosophy. Philosophy is an activity, and addresses

### Test Item File. Full file at

Test Item File 107 CHAPTER 1 Chapter 1: Basic Logical Concepts Multiple Choice 1. In which of the following subjects is reasoning outside the concern of logicians? A) science and medicine B) ethics C)

### Tutorial A02: Validity and Soundness By: Jonathan Chan

A02.1 Definition of validity Tutorial A02: Validity and Soundness By: One desirable feature of arguments is that the conclusion should follow from the premises. But what does it mean? Consider these two

### LOGIC ANTHONY KAPOLKA FYF 101-9/3/2010

LOGIC ANTHONY KAPOLKA FYF 101-9/3/2010 LIBERALLY EDUCATED PEOPLE......RESPECT RIGOR NOT SO MUCH FOR ITS OWN SAKE BUT AS A WAY OF SEEKING TRUTH. LOGIC PUZZLE COOPER IS MURDERED. 3 SUSPECTS: SMITH, JONES,

### 16. Universal derivation

16. Universal derivation 16.1 An example: the Meno In one of Plato s dialogues, the Meno, Socrates uses questions and prompts to direct a young slave boy to see that if we want to make a square that has

### CHAPTER THREE Philosophical Argument

CHAPTER THREE Philosophical Argument General Overview: As our students often attest, we all live in a complex world filled with demanding issues and bewildering challenges. In order to determine those

### Logic Appendix: More detailed instruction in deductive logic

Logic Appendix: More detailed instruction in deductive logic Standardizing and Diagramming In Reason and the Balance we have taken the approach of using a simple outline to standardize short arguments,

What is an argument? PHIL 110 Lecture on Chapter 3 of How to think about weird things An argument is a collection of two or more claims, one of which is the conclusion and the rest of which are the premises.

### Thinking and Reasoning

Syllogistic Reasoning Thinking and Reasoning Syllogistic Reasoning Erol ÖZÇELİK The other key type of deductive reasoning is syllogistic reasoning, which is based on the use of syllogisms. Syllogisms are

### Logic -type questions

Logic -type questions [For use in the Philosophy Test and the Philosophy section of the MLAT] One of the questions on a test may take the form of a logic exercise, starting with the definition of a key

### The Little Logic Book Hardy, Ratzsch, Konyndyk De Young and Mellema The Calvin College Press, 2013

The Little Logic Book Hardy, Ratzsch, Konyndyk De Young and Mellema The Calvin College Press, 2013 Exercises for The Little Logic Book may be downloaded by the instructor as Word documents and then modified

### Also, in Argument #1 (Lecture 11, Slide 11), the inference from steps 2 and 3 to 4 is stated as:

by SALVATORE - 5 September 2009, 10:44 PM I`m having difficulty understanding what steps to take in applying valid argument forms to do a proof. What determines which given premises one should select to

### Chapter 1. Introduction. 1.1 Deductive and Plausible Reasoning Strong Syllogism

Contents 1 Introduction 3 1.1 Deductive and Plausible Reasoning................... 3 1.1.1 Strong Syllogism......................... 3 1.1.2 Weak Syllogism.......................... 4 1.1.3 Transitivity

### PHIL2642 CRITICAL THINKING USYD NOTES PART 1: LECTURE NOTES

PHIL2642 CRITICAL THINKING USYD NOTES PART 1: LECTURE NOTES LECTURE CONTENTS LECTURE 1: CLAIMS, EXPLAINATIONS AND ARGUMENTS LECTURE 2: CONDITIONS AND DEDUCTION LECTURE 3: MORE DEDUCTION LECTURE 4: MEANING

### Logic. A Primer with Addendum

Logic A Primer with Addendum The Currency of Philosophy Philosophy trades in arguments. An argument is a set of propositions some one of which is intended to be warranted or entailed by the others. The

### A R G U M E N T S I N A C T I O N

ARGUMENTS IN ACTION Descriptions: creates a textual/verbal account of what something is, was, or could be (shape, size, colour, etc.) Used to give you or your audience a mental picture of the world around

### INTRODUCTION TO LOGIC 1 Sets, Relations, and Arguments

INTRODUCTION TO LOGIC 1 Sets, Relations, and Arguments Volker Halbach Pure logic is the ruin of the spirit. Antoine de Saint-Exupéry The Logic Manual The Logic Manual The Logic Manual The Logic Manual

### Chapter 1 - Basic Training

Logic: A Brief Introduction Ronald L. Hall, Stetson University Chapter 1 - Basic Training 1.1 Introduction In this logic course, we are going to be relying on some mental muscles that may need some toning

### b) The meaning of "child" would need to be taken in the sense of age, as most people would find the idea of a young child going to jail as wrong.

Explanation for Question 1 in Quiz 8 by Norva Lo - Tuesday, 18 September 2012, 9:39 AM The following is the solution for Question 1 in Quiz 8: (a) Which term in the argument is being equivocated. (b) What

### ELEMENTS OF LOGIC. 1.1 What is Logic? Arguments and Propositions

Handout 1 ELEMENTS OF LOGIC 1.1 What is Logic? Arguments and Propositions In our day to day lives, we find ourselves arguing with other people. Sometimes we want someone to do or accept something as true

### Example Arguments ID1050 Quantitative & Qualitative Reasoning

Example Arguments ID1050 Quantitative & Qualitative Reasoning First Steps to Analyzing an Argument In the following slides, some simple arguments will be given. The steps to begin analyzing each argument

### How to Write a Philosophy Paper

How to Write a Philosophy Paper The goal of a philosophy paper is simple: make a compelling argument. This guide aims to teach you how to write philosophy papers, starting from the ground up. To do that,

### Philosophical Arguments

Philosophical Arguments An introduction to logic and philosophical reasoning. Nathan D. Smith, PhD. Houston Community College Nathan D. Smith. Some rights reserved You are free to copy this book, to distribute

### Between the Actual and the Trivial World

Organon F 23 (2) 2016: xxx-xxx Between the Actual and the Trivial World MACIEJ SENDŁAK Institute of Philosophy. University of Szczecin Ul. Krakowska 71-79. 71-017 Szczecin. Poland maciej.sendlak@gmail.com

### The antecendent always a expresses a sufficient condition for the consequent

Critical Thinking Lecture Four October 5, 2012 Chapter 3 Deductive Argument Patterns Diagramming Arguments Deductive Argument Patterns - There are some common patterns shared by many deductive arguments

### HANDBOOK. IV. Argument Construction Determine the Ultimate Conclusion Construct the Chain of Reasoning Communicate the Argument 13

1 HANDBOOK TABLE OF CONTENTS I. Argument Recognition 2 II. Argument Analysis 3 1. Identify Important Ideas 3 2. Identify Argumentative Role of These Ideas 4 3. Identify Inferences 5 4. Reconstruct the

Chapter 1 What Is Philosophy? Thinking Philosophically About Life CHAPTER SUMMARY Philosophy is a way of thinking that allows one to think more deeply about one s beliefs and about meaning in life. It

### Announcements. CS243: Discrete Structures. First Order Logic, Rules of Inference. Review of Last Lecture. Translating English into First-Order Logic

Announcements CS243: Discrete Structures First Order Logic, Rules of Inference Işıl Dillig Homework 1 is due now Homework 2 is handed out today Homework 2 is due next Tuesday Işıl Dillig, CS243: Discrete

### Logic for Computer Science - Week 1 Introduction to Informal Logic

Logic for Computer Science - Week 1 Introduction to Informal Logic Ștefan Ciobâcă November 30, 2017 1 Propositions A proposition is a statement that can be true or false. Propositions are sometimes called

### Announcements. CS311H: Discrete Mathematics. First Order Logic, Rules of Inference. Satisfiability, Validity in FOL. Example.

Announcements CS311H: Discrete Mathematics First Order Logic, Rules of Inference Instructor: Işıl Dillig Homework 1 is due now! Homework 2 is handed out today Homework 2 is due next Wednesday Instructor:

### Chapter 8 - Sentential Truth Tables and Argument Forms

Logic: A Brief Introduction Ronald L. Hall Stetson University Chapter 8 - Sentential ruth ables and Argument orms 8.1 Introduction he truth-value of a given truth-functional compound proposition depends

### Richard L. W. Clarke, Notes REASONING

1 REASONING Reasoning is, broadly speaking, the cognitive process of establishing reasons to justify beliefs, conclusions, actions or feelings. It also refers, more specifically, to the act or process

PHILOSOPHY ESSAY ADVICE One: What ought to be the primary objective of your essay? The primary objective of your essay is not simply to present information or arguments, but to put forward a cogent argument

### Lecture 17:Inference Michael Fourman

Lecture 17:Inference Michael Fourman 2 Is this a valid argument? Assumptions: If the races are fixed or the gambling houses are crooked, then the tourist trade will decline. If the tourist trade declines

### Academic argument does not mean conflict or competition; an argument is a set of reasons which support, or lead to, a conclusion.

ACADEMIC SKILLS THINKING CRITICALLY In the everyday sense of the word, critical has negative connotations. But at University, Critical Thinking is a positive process of understanding different points of

### Portfolio Project. Phil 251A Logic Fall Due: Friday, December 7

Portfolio Project Phil 251A Logic Fall 2012 Due: Friday, December 7 1 Overview The portfolio is a semester-long project that should display your logical prowess applied to real-world arguments. The arguments

### A Brief Introduction to Key Terms

1 A Brief Introduction to Key Terms 5 A Brief Introduction to Key Terms 1.1 Arguments Arguments crop up in conversations, political debates, lectures, editorials, comic strips, novels, television programs,

### Unit. Categorical Syllogism. What is a syllogism? Types of Syllogism

Unit 8 Categorical yllogism What is a syllogism? Inference or reasoning is the process of passing from one or more propositions to another with some justification. This inference when expressed in language

### T. Parent. I shall explain these steps in turn. Let s consider the following passage to illustrate the process:

Reconstructing Arguments Argument reconstruction is where we take a written argument, and re-write it to make the logic of the argument as obvious as possible. I have broken down this task into six steps:

### Introduction to Philosophy Crito. Instructor: Jason Sheley

Introduction to Philosophy Crito Instructor: Jason Sheley Recall again our steps for doing philosophy 1) What is the question? 2) What is the basic answer to the question? 3) What reasons are given for

### Conditionals II: no truth conditions?

Conditionals II: no truth conditions? UC Berkeley, Philosophy 142, Spring 2016 John MacFarlane 1 Arguments for the material conditional analysis As Edgington [1] notes, there are some powerful reasons

### Appendix: The Logic Behind the Inferential Test

Appendix: The Logic Behind the Inferential Test In the Introduction, I stated that the basic underlying problem with forensic doctors is so easy to understand that even a twelve-year-old could understand

### INDUCTION. All inductive reasoning is based on an assumption called the UNIFORMITY OF NATURE.

INDUCTION John Stuart Mill wrote the first comprehensive study of inductive logic. Deduction had been studied extensively since ancient times, but induction had to wait until the 19 th century! The cartoon

### 1/19/2011. Concept. Analysis

Analysis Breaking down an idea, concept, theory, etc. into its most basic parts in order to get a better understanding of its structure. This is necessary to evaluate the merits of the claim properly (is

### Study Guides. Chapter 1 - Basic Training

Study Guides Chapter 1 - Basic Training Argument: A group of propositions is an argument when one or more of the propositions in the group is/are used to give evidence (or if you like, reasons, or grounds)

### I would like to summarize and expand upon some of the important material presented on those web pages and in the textbook.

Hello once again! Essay Assignment 1 I would like to give you some suggestions now that should help you as you are working on Essay Assignment 1. This presentation is somewhat long, but the information

### What we want to know is: why might one adopt this fatalistic attitude in response to reflection on the existence of truths about the future?

Fate and free will From the first person point of view, one of the most obvious, and important, facts about the world is that some things are up to us at least sometimes, we are able to do one thing, and

### There are a number of writing problems that occur frequently enough to deserve special mention here:

1. Overview: A. What is an essay? The primary focus of an essay is to explain and clarify your understanding of and opinion about a particular topic, much like an editorial or essay article in a newspaper

### Instructor s Manual 1

Instructor s Manual 1 PREFACE This instructor s manual will help instructors prepare to teach logic using the 14th edition of Irving M. Copi, Carl Cohen, and Kenneth McMahon s Introduction to Logic. The

### Revisiting the Socrates Example

Section 1.6 Section Summary Valid Arguments Inference Rules for Propositional Logic Using Rules of Inference to Build Arguments Rules of Inference for Quantified Statements Building Arguments for Quantified

### PHI 1500: Major Issues in Philosophy

PHI 1500: Major Issues in Philosophy Session 3 September 10 th, 2014 Methods: Reading Philosophy 1 Reading Philosophy As we saw from Russell s essay, it can be difficult to decode what an author is saying,

### Philosophy 1100: Introduction to Ethics. Critical Thinking Lecture 2. Background Material for the Exercise on Inference Indicators

Philosophy 1100: Introduction to Ethics Critical Thinking Lecture 2 Background Material for the Exercise on Inference Indicators Inference-Indicators and the Logical Structure of an Argument 1. The Idea

### Comments on Truth at A World for Modal Propositions

Comments on Truth at A World for Modal Propositions Christopher Menzel Texas A&M University March 16, 2008 Since Arthur Prior first made us aware of the issue, a lot of philosophical thought has gone into

632 Notre Dame Journal of Formal Logic Volume 35, Number 4, Fall 1994 Reply to Robert Koons ANIL GUPTA and NUEL BELNAP We are grateful to Professor Robert Koons for his excellent, and generous, review

### Logic: A Brief Introduction. Ronald L. Hall, Stetson University

Logic: A Brief Introduction Ronald L. Hall, Stetson University 2012 CONTENTS Part I Critical Thinking Chapter 1 Basic Training 1.1 Introduction 1.2 Logic, Propositions and Arguments 1.3 Deduction and Induction

### 2016 Philosophy. Higher. Finalised Marking Instructions

National Qualifications 06 06 Philosophy Higher Finalised Marking Instructions Scottish Qualifications Authority 06 The information in this publication may be reproduced to support SQA qualifications only

### Intro Viewed from a certain angle, philosophy is about what, if anything, we ought to believe.

Overview Philosophy & logic 1.2 What is philosophy? 1.3 nature of philosophy Why philosophy Rules of engagement Punctuality and regularity is of the essence You should be active in class It is good to

### Philosophical Methods Revised: August, 2018

Introduction Philosophical Methods Revised: August, 2018 What is philosophy? This is a difficult question to answer well, so I ll start by saying what philosophy is not. Philosophy is not just speculation