CRT 205: Critical Thinking Weeks 6 & 7 :CRT 205: Critical Thinking Weeks 6 & 7 Analyzing & Evaluating Arguments Deductive & Inductive Reasoning


Overview :Overview Chapter 7 Week 6 Assignments Week 7 Assignments


Chapter 7 :Chapter 7


Definitions :Definitions Inductive Reasoning Proceeding from particular facts to a general conclusion A conclusion is proposed based on more than what the premises present Logic: A process by which premises are used to estimate judgments about a class of things (birds, people, rocks, places, etc). Deductive Reasoning A conclusion is drawn from a set a premises and uses no other information other than that presented in the premises Logic: A conclusion cannot be false if the premises are true Premise A proposition help or actually supporting an argument (facts, statements, observations, etc).


Logic :Logic Study of principals by which arguments are evaluated.


Arguments :Arguments Premise Facts, examples, reasoning for making a specific conclusion Example: 90% of all students study at night; 50% of students fail at least one class Conclusion The decision that was made Example: Studying in the morning reduces the chances of failing a course, so I will study in the morning.


Words as Clues :Words as Clues Since Because For In view of This is implied by


Words as Clues :Words as Clues Thus Therefore Hence This shows that This suggests that Consequently So Accordingly This implies that This proves that Example (Bad Logic): Marta does not like green olives; therefore, she will not like black olives. Example (Good Logic): Stephen is allergic to shellfish, consequently, he can not eat shrimp.


Conclusions Used as Premises :Conclusions Used as Premises


Conclusion Premise Relationship :Conclusion Premise Relationship


Unstated Premises :Unstated Premises Example 1: Tara doesn’t like green apples, so she will not eat the pie. Unstated premise – there are green apples in the pie. Example 2: Emily’s birthday is in April, so we will not celebrate it for another year. Unstated premise – it is after Emily’s birthday. Example 3: In order to pass CRT 205 students must earn no less than 600 points. Genevieve will not pass CRT 205. Unstated premise – Genevieve has less than 600 points in CRT 205.


Unstated Conclusions :Unstated Conclusions Example 1: Ava likes Cheez-Its and she is hungry for a snack; the only food Ava has is a box of Cheez-Its in her pantry. Missing conclusion – Ava will eat the Cheez-Its in her pantry for a snack. Example 2: Byron went to the library last week (six days ago) and checked out a book on chemistry. Byron’s library book is due today. Missing conclusion – Byron will return or renew his library book today. Example 3: The teacher said there would be a test on Thursday. David has not started studying for Thursday’s test. Missing conclusion – David needs to start studying for Thursday’s test.


Arguments vs. Explanations :Arguments vs. Explanations Argument Shows that a claim is true Example: The economy is down because the stock market is in a decline, inflation is high, and unemployment is high. Explanation Shows what caused something, how it works, or the purpose it serves Example: The success of the economy is dependent upon a number of things including but not limited to the stock market, inflation, and unemployment rates.


Deductive Reasoning (Logic) :Deductive Reasoning (Logic) Deductive reasoning: Uses premises to prove or demonstrate a conclusion’s validity Pattern: This is premise is true, this premise is true, so the conclusion must be true. Special consideration: If the premises are true but the conclusion is false because a premise was not considered the conclusion would be valid but it would not necessarily be true. Ex: Professor Westlake has a blue car and a blue bike. Professor Westlake buys things that are the color blue. Well my car and bike are black, if my bike and car were blue it might be true that I buy things that are blue, but the premise (facts) are not true; therefore, the argument is valid in that the logic is good and the premise is false because it is not true.


Drawing Deductive Conclusions :Drawing Deductive Conclusions


Inductive Reasoning (Logic) :Inductive Reasoning (Logic) Inductive Reasoning: Premises support rather than prove or demonstrate a conclusion Pattern: This is a premise, this is a premise, based on this information I came to this conclusion. Ex.: Plastic bags released in the earth’s waterways kill marine life every day; therefore, if we want to preserve our marine life we should not dump plastic bags into our waterways.


Drawing Inductive Conclusions :Drawing Inductive Conclusions


Identifying the Argument :Identifying the Argument Identify what is not apart of the argument: Reports Explanations Fallacies Persuasive tactics And other words and phrases Identify the premises Proving Supporting Valid Invalid Identify the conclusion What is the conclusion What is the conclusion based on


Evaluating Arguments :Evaluating Arguments Do the premises prove or support the conclusion? (This tells us what kind of argument we are evaluating.) Is the argument valid or strong? Why? (This tells us if there are issues to consider in terms of validity.) Are the premises true? (This tells us whether the conclusion is good or not.) Does the argument use fallacies to distract our attention? (This helps us distinguish between premises and fallacious distracters.)


Evaluating an Argument :Evaluating an Argument Remember the keys to identifying and evaluating an argument are being able to identify what someone is trying to convince you of and how that person is trying to convince you.


Week 6 Assignments :Week 6 Assignments


Week 6 Assignments :Week 6 Assignments Discussion Questions 1 & 2 200 word min. response Due Tuesday/Thursday Post as a message, not an attachment in Main forum Participation Respond to challenge question Respond to your classmate’s/instructor’s posts/questions Post min. 2 substantive posts on 3 of 7 days of the week


Week 6 Assignments :Week 6 Assignments Review Quizzes from Ch. 7 (total 4) Argument Quiz I Deductive/Inductive Logic Quiz Unstated Premises Quiz Evaluating Arguments Quiz


Week 7 Assignments :Week 7 Assignments


Week 7 Assignments :Week 7 Assignments CheckPoint 1 Argument Validity Use the worksheet Post in the body of a message Just go through and answer the questions If you use the notes should take you less than 30 min. CheckPoint 2 Critical Thinking Quiz Only get 1 chance to take it Use the link on your aXcess page You get what you score for points so try your best Use the notes to help you If you don’t rush and you use the notes this should take between 30 and 45 min.


Week 7 Assignments :Week 7 Assignments Argument Evaluation Use the worksheet Remember that an argument is BOTH the premises and the conclusion Do not include fallacies or rhetorical devices Explain your answers and use supporting details Use complete sentences Spell check & proof-read your work Use “Controlling Irrational Fears After 9/11” on pp. 456-458 of Appendix 1 (of the text – located on aXcess) to answer the questions