Midterm

The midterm will be held at the beginning of class on Monday, November 1st. It's worth 15% of your overall grade, and will cover everything we've done in class so far:

• definitions of 'logic,' 'reasoning,' and 'argument'
  
• evaluating arguments
• types of arguments:
  -deductive (aim for certainty, are valid/invalid and sound/unsound)
  -inductive (generalizing from examples, depend on large, representative samples)
  -args about cause/effect (correlation vs. causation)
  -abductive (inferences to the best explanation)
  
• the 12 fallacies covered in class so far
  

Get to studying!

Let's Be Diplomatic: Straw Person

Here's some stuff on the straw man fallacy:

• Politicians love to distort their opponents' positions. Even Obama does it.
• Politicians aren't alone: we do it, too. Often we distort arguments for claims we disagree with without even realizing it. This is because we have trouble coming up with good reasons supporting a conclusion that we think is false, so we have a tendency to make up bad reasons and attribute them to our opponents.
  
• Hire your own professional straw man!

Also, speaking of red herrings, here's a cute cat picture:

Wait, we weren't just speaking of red her--Oh. I see what you did there.

Clever.

That's an Ad Hominem, You Jerk

Here are some links on the ad hominem (personal attack) fallacy:

• Sure, some critics of Obama are racist, but does that mean we can dismiss their arguments? As much as we might want to, logically, no we cannot!
• Some variants on the personal attack: tu quoque (hypocrite!) and guilt by association (she hangs around bad people!).
• I should note that tu quoque isn't always fallacious reasoning.
  
• "The ad hominem rejoinders—ready the ad hominem rejoinders!"
• Remember our rallying cry: "STUPID PEOPLE SOMETIMES SAY SMART THINGS."
  

Get to studying, you ignorant sluts.

Accent the Pity

Here is a pair of comics playing off the fallacy of accent:


This next one pulls off a rare double-accent:

And here's an ad that's clearly appealing to pity. Whadaya think? Is this appeal relevant or irrelevant? Let us know in the comments to this post.

Take My Wife, as Amphiboly

Here's some stand up from Henny Youngman, the violin-toting comedian who came up with "Take my wife... please!" How many jokes rely on amphiboly?

Homework #2

Just a reminder that homework #2 is due at the beginning of class on Monday , October 25th. The assignment is to determine the fallacies in the arguments of #1 (a through l) on pages 138-139 and #1 (a through t) of exercise 5-3 on pages 150-151 of our textbook. Some arguments don't commit any fallacy.

Fallacies, Fallacies, Everywhere

Looking for links on fallacies and equivocation? This is your post! First, there's a nice series of short articles on a bunch of different fallacies, including many that aren't in our book.... but also an entry on equivocation.

Speaking of, my best friend the inter-net has some nice examples of the fallacy of equivocation. Here is one good one:

A feather is light.

What is light cannot be dark.
Therefore, a feather cannot be dark.

Murder on the Abductive Express

Here's a paper that explains why I disagree with our textbook's explanation of the scientific method. It's important to consider and test multiple possible explanations rather than a single hypothesis:

• J.R. Platt's "Strong Inference" (pdf)

(NOTE: Platt uses the word "inductive" in a more general way than we do in class, to refer to any non-deductive kind of reasoning--that is, arguments that don't attempt to absolutely prove their conclusion.)

Also, in honor of abductive arguments, here's a dinosaur comic murder mystery.



P.S. I'm halfway through reading this book: Inference to the Best Explanation by Peter Lipton.

Correlatious

Here's yet another stick-figure comic. This one's about correlation and causation.

Correlation is a tricky concept. We tend to see the world in all-or-nothing terms, rather than in shades of probability.

Our Inductive Minds

Here are some more thoughtful links on inductive reasoning (or arguments by example).

• What are the benefits and dangers of generalizations?
• What makes stereotyping illogical?
• Beware: we often make snap judgments before thinking through things. Then when we do think through things, we just wind up rationalizing our snap judgments.