Logical Reasoning & Argument (Logos) Chapter 12

Reasoning from Generalization Induction – from specific to general.  My Toyota has acceleration problems.  Your Toyota has acceleration problems.  Bob’s Toyotas have acceleration problems. Conclusion: Toyotas have acceleration problems. Deduction – from general to specific.  Smoking cigarettes causes cancer.  Marlboro is a cigarette. Conclusion: Smoking Marlboros causes cancer.

Reasoning from Analogy May be either literal or figurative. Comparing one or more items that are similar in some way.  Tennessee should legalize medical marijuana.  Alaska legalized medical marijuana back in Reasoning: Tennessee and Alaska are both states and are therefore similar.

Reasoning from Cause Typically either from cause-to-effect or from effect-to-cause. From Cause to EffectFrom Effect to Cause It’s 10 below zero outside.I was late for work today. My car battery won’t start.My car battery wouldn’t start.

Reasoning from Sign Reasoning from circumstances or clues.  He drives a Porsche. He must be wealthy.  She is wet. It must be raining.  My brakes are squealing. I need new brake pads.

Toulmin’s Model of Reasoning: A “Snapshot” of an Argument Grounds = evidence or data

Toulmin’s Model of Reasoning Claim = the point the arguer is trying to prove

Toulmin’s Model of Reasoning Warrant = links grounds and claim; “Since”

Toulmin’s Model of Reasoning Backing = Support for the warrant

Toulmin’s Model of Reasoning Qualifier = Degree of certainty of the argument

Toulmin’s Model of Reasoning Rebuttal = Reasons that refute the argument; “Unless”

Example using Toulmin Model

Another Example from our Text: George smokes heavily (G). Probably (Q) Heavy smokers are more likely to develop cancer than non-smokers. (W) Research from U.S. Dept. of Health (B) George is likely to develop cancer. (C) Unless George is lucky, or unless a cure is found, or unless he has unusual immunity, or unless he stops smoking. (R)

Our Own Example _______ was the best movie of What evidence supports this claim? What background information supports the warrant? What is the connection between the grounds & claim? How certain are you of this warrant? (Very, probably, certainly, absolutely, possibly, maybe, % sure, etc.) Unless...

Fallacies (to name a few) Overgeneralization (“Everybody thinks” or “All”) False causation (post hoc ergo propter hoc) Red herring (irrelevant information) Either/or (false polarization) Loaded questions Arguing in a circle Ad hominem Appeal to prejudice False appeal to authority Want to know more? Check out ex.html ex.html

A 20 pt. “Think Piece” Assignment: Between now and the end of the semester, find a fallacy. Write out the fallacy and give the name of the fallacy. This assignment does not have to be typed. Fallacies are everywhere! (Wait, is that overgeneralization? No!)