Philosophy lecture on logical satisfactoriness

This is a lecture on Philosophical concepts.

1. PHIL 1003: Intro to Philosophy Week 2a (March 15-19) Edwin Etieyibo, PhD (Alberta), Philosophy Department, Wits University 1

2. Readings for the week Week 2 (Monday 15 March — Friday 19 March) 2. Elements/Features of Good Arguments ( a) Joyce Jones — “Separating Good Arguments from Bad ” (b) Robert M. Johnson — “Good Argument, Deductive Validity, and Inductive Strength” 2

3. We need to learn Argument evaluation skills and concepts Our mastering the various argument evaluation skills and concepts will make us to be good at critical thinking and in logic (we’ll be good critical thinkers and logicians). able to tell whether a given argument is good or not . able to tell whether some reasons that are offered for something (a belief, position) are better than others . 3

4. Learning goals this lecture and next (Week 2a & 2b of March 15-19) Definitions Kinds of evaluations of argument, logical satisfactoriness, support, deductive validity, nondeductive strength/argument, relevance, adequacy Examples Logically unsatisfactory arguments with (Ex 1) a true conclusion, (Ex 2) true premises, (Ex 3) true everything Deductively valid arguments with (Ex 4) true everything, (Ex 5) false everything Nondeductively (Ex 6) strong and (Ex 7) weak arguments Relevance and adequacy ( examples) 4

5. Discussion groups activities for week 2 In your discussion groups you can bring up different things and issues that are covered during this week’s lectures. But to also give your discussions a focus you and your tutor may want to engage with the following activities/exercises. You have a feeling that your partner is cheating on you, but you do not know for sure. How would you go about gathering evidence — evidence that is relevant and adequate to support the claim (proposition) or conclusion that your partner is cheating on you? Try putting the evidence that you’ve gathered in an argument form, both as a deductive argument and a non-deductive argument. And in your discussion group discuss (a) how good the evidence is for the claim or conclusion, (b) how well the evidence has been stated in the two arguments forms (deductive and non-deductive ), and (c) how to strengthen the arguments. 5

6. Definition: kinds of evaluation of arguments Rhetorical argument How persuasive is the argument? Logical argument How reasonable is the argument? An argument may be persuasive and yet not logical (or reasonable) – examples: demagogue or rabble-rouser, lawyers, etc. An argument may be logical and yet not persuasive (remember Gail’s hamburger example). 6

7. Definition: logical satisfactoriness This is a preliminary definition of logical satisfactoriness. An argument is logically satisfactory iff (a) the premises support the conclusion, and (b) we are justified in believing that the premises are true. 7

8. Example 1: Unsatisfactory argument with true conclusion Lesotho is a wealthy nation. All African nations are wealthy nations. \ Lesotho is an African nation. 8

9. Example 2: Unsatisfactory argument with true premises Thailand is a developing country. All African nations are developing countries. \ Thailand is an African nation. 9

10. Example 3: Unsatisfactory argument with true everything 1. Johannesburg is a city in South Africa. 2. Johannesburg is a bigger city than Pretoria. \ Johannesburg is a smaller city than New York. 10