Chapter 3: Reality Assumptions This chapter will cover Reality assumptions Patterns of deductive reasoning Using deductive reasoning to test logic, discover truth, make decisions, avoid stereotyping, and understand argument. Why is it useful to learn the patterns of deductive reasoning? Pg. 86

Reality Assumptions Beliefs about what is true and factual about the world. Based on unique experience of individual Discuss the notion of assumptions- often hidden and though sometimes directly stated by the speaker, they are usually implied. Also call factual or descriptive assumptions

Detecting Reality Assumptions Toulmin’s Model Issue: Should we use the SAT or ACT scores to predict success in college? When considering an issue, what are the reality assumptions?

Toulmin’s Model Claim - Students should not apply to colleges at which SAT scores are 200 points higher than theirs. Warrant (Reality Assumption) Scores are accurate predictions of how well a student is prepared Reason Students will not likely succeed Based on Value-Education is valued but how education is measured varies according to different assumptions

Test only predicts level of struggle for first year. Toulmin’s Model Claim Colleges should not use standardized test scores as a measure of success. Reason Test only predicts level of struggle for first year. Warrant (Reality Assumption) Students success based on character qualities that are not measured by the tests. Based on What is the reality assumption?

Toulmin’s Model Issue: Should trials and executions be televised

Toulmin’s Model Claim: Trials and executions should be televised Warrant (Reality Assumption) Televising trials would inform the public about our judicial system. Reason: Public has the right to have more information about the courts and the judicial system. Based on What is the reality assumption? What is the value assumption? Which has priority? Warrant (Value Assumption) Freedom of information is an important value

Reasoning Deductive Reasoning General statement to a specific instance Deductive reasoning aims to give us certainty about what is true in a given situation. Certainty is established when the premises (reasons) are true and stated in correct form.

Reasoning Deductive Inductive Aims for Certainty General to Specific Gives us Probabilities Specific to General Chapter 6

Deductive Reasoning Syllogism- a classic example All men are mortal. (major premise) Socrates is a man. (minor premise) Therefore, Socrates is mortal. (conclusion) Defining a syllogism

Deductive Reasoning Validity Correct form makes an argument valid (logical). Accurate content makes it true. When the form is valid and the content is true, the argument is sound.

Deductive Reasoning is content true? All students eat pizza. Claire is a student at CSU. Is form valid? Therefore, Claire eats pizza. Is it sound? No

Deductive Reasoning is content true? All women are terrible drivers. Jane is a woman. Is form valid? Therefore, Jane is a terrible driver. Is it sound? Yes

Deductive Reasoning Pattern of Deductive reasoning All As are Bs. Categorical statement m is A. Therefore, m is B

Deductive Reasoning Categorical Statement All As are Bs. A B A statement in which members of one class are said to be included in Another class. Example

Conditional/hypothetical syllogism Modus ponens: ‘the way of affirmation’: the antecedent leads to the consequent. If A, then B A Therefore, B B A A is the antecedent; B is the consequent.

Conditional/hypothetical syllogism Modus tollens: ‘denying the consequent.’ If A, then B Not A Therefore not B B A If I have strep throat, then the culture will be positive. But the culture is not positive. So, I don’t have strep throat.

Deductive Reasoning Questionable Premises All drivers who speed are subject to a fine. You are speeding. Which premise can be contested? Therefore, you are subject to a fine.

Deductive Reasoning Enthymeme Key part is implied rather than directly stated.

Deductive Reasoning Sound Argument: Correct Form True Premises False Sound Argument: Correct Form True Premises Unsound Argument: Correct Form Untrue Premises Valid Unsound Argument: Incorrect Form, True Premises Unsound Argument: Incorrect Form, Untrue Premises Invalid

Deductive Reasoning Deductive reasoning can: Uncover Reality Assumptions Discover Truth and Make Decisions Combat Prejudice and Stereotyping

Skill A critical thinker uses reasoning to discover truth and prevent stereotyping

Chapter 3: Reality Assumptions Checkup Reality versus value assumptions Validity in an argument What makes a deductive argument sound What does deductive reasoning aim to establish