Homework #2

Just a reminder that homework #2 is due at the beginning of class on Monday, November 2nd. The assignment is to determine the fallacies in the arguments of #1 (a through t) of exercise 5-3 on pages 150-151 of our textbook.

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 that paper I talked about in class about the importance of considering and testing 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.)

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

Causalicious

Here's a great stick-figure comic about correlation.

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

2^100 > Sean

I was way off:

"Two to the 100th power is 1,267,650,600,228,229,401,496,703,205,376.

"In the US number naming system, it is one nonillion, 267 octillion, 650 septillion, 600 sextillion, 228 quintillion, 229 quadrillion, 401 trillion, 496 billion, 703 million, 205 thousand, 376."

That's, uh, just a tad bigger than 35 trillion.

My bad.

(Thanks, Andrew, for calling me on this!)

Analogize This

Is the world like a machine? Does that mean there's a god? Here are some links on the design argument for God's existence.

• Here is a nice explanation of the design argument, along with an explanation of another wacky arg for god's existence.
  
• Here is an audio interview on David Hume's criticisms of the design arg.
  
• One philosophers' take on the debate between evolution and intelligent design.
• Is our universe fine-tuned for life? Maybe not.
• Wait, can science even judge religious claims, or are they talking about different things? Maybe an inference to the best explanation can help us...
  
• What about all the "design flaws" in nature? Are they evidence against a supreme designer?

One last thing in honor of arguments by analogy:

Group Presentations

Here are the assigned groups for the group presentations on fallacies, along with your topics and the date of each presentation:

1. Ad Hominem & Appeal to Force (10/26): Joy, Kelly, Pat Ba.
2. Appeal to Pity & Popular Appeal (10/26): Andrew B., Emily S., Pat Br.
   
3. Appeal to Ignorance & Hasty Generalization (11/02): Don, Erin, Jenda, Jennifer
   
4. Straw Man & Red Herring (11/02): Andrew S., Darren, Kevin, Matt, Scott
   
5. Begging the Question & Loaded Question (11/09): Jackie, Joe M., Joey, Kiley
   
6. Appeal to Authority & False Dilemma (11/09): Devin, George, Len, T.J.
   
7. Slippery Slope & The Naturalistic Fallacy (11/16): Alyson, Emily T., Joe D., Nicole
   

Learning From Experience

(Looking for the homework assignment? Click here!)

Here's some stuff on inductive arguments. First, a video of comedian Lewis Black describing his failure to learn from experience every year around Halloween:


Next, a stick figure comic offers a pretty bad argument. Why is it bad? (Let us know in the comments!)

There's another stick-figure comic about scientists' efforts to get as big a sample size as they can to improve their arguments.

Finally, some more thoughtful links.

• 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.

Evaluating Deductive Args

(Looking for the homework assignment? Click here!)

Here are the answers to the handout on evaluating deductive arguments that we did as group work in class. Perhaps I should have titled the handout "So Many Bad Args!"

1) All humpback whales are whales.
All whales are mammals.
All humpback whales are mammals.

P1- true
P2- true
structure- valid
overall - sound

2) (from Stephen Colbert)
Bush was either a great prez or the greatest prez.
Bush wasn’t the greatest prez.
Bush was a great prez.

P1- questionable ("great" is subjective)
P2- questionable ("great" is subjective)
structure- valid (it's either A or B; it's not A; so it's B)
overall- unsound (bad premises)

3) Some cats can speak German.
Sean has a cat.
Sean's cat can speak German.

P1- false
P2- true! (I have two; there they are! ------------>)
structure- invalid (the 1st premise only says some can speak German; Sean's cat could be one of the ones that doesn't)
overall- unsound (bad structure)

4) All knock-knock jokes are annoying.
Some knock-knock jokes are funny.
Some annoying things are funny.

P1- questionable ("annoying" is subjective)
P2- questionable ("funny" is subjective)
structure- valid (the premises establish that some knock-knock jokes are both annoying and funny; so some annoying things [those jokes] are funny)
overall - unsound (bad premises)

5) All whales are mammals.
All whales live in the ocean.
All mammals live in the ocean.

P1- true
P2- true (if interpreted to mean "Whales are the sorts of creatures whose natural habitat is the ocean.") or false (if interpreted to mean "Each and every living whale lives in the ocean," since some whales, like Shamu, live in SeaWorld or other zoos)
structure- invalid (we don't know much about the relationship between mammals and creatures that living in the ocean just from the fact that whales belong to each of those groups)
overall- unsound (bad structure)

6) Some dads have beards.
All bearded people are mean.
Some dads are mean.

P1- true
P2- questionable ("mean" is subjective)
structure- valid (if all the people with beards were mean, then the dads with beards would be mean, so some dads would be mean)
overall- unsound (bad 2nd premise)

7) This class is boring.
All boring things are taught by Sean
This class is taught by Sean.

P1-questionable ("boring" is subjective)
P2- false (nearly everyone would agree that there are some boring things not associated with your teacher Sean)
structure- valid
overall- unsound (bad premises)

8) All students in this room are mammals.
All humans are mammals.
All students in this room are humans.

P1- true
P2- true
structure- invalid (it's the same structure as argument #10 below; the premises only tell us that students and humans both belong to the mammals group; we don't know enough about the relationship between students and humans from this; for instance, what if a dog were a student in our class?)
overall- unsound (bad structure)

9) All hornets are wasps.
All wasps are insects.
All insects are scary.
All hornets are scary.

P1- true!
P2- true
P3- questionable ("scary" is subjective)
structure- valid (same structure as in argument #1, just with an extra premise)
overall- unsound (bad 3rd premise)

10) All women are mammals.
All men are mammals.
All men are women.

P1- true
P2- true
structure- invalid (just because men and women belong to the same group doesn't mean that men are women; same bad structure as in arg #8)
overall- unsound (bad structure)

11) If Sean sings, then students cringe.
Sean is singing right now.
Students are cringing right now.

P1- questionable (since you haven't heard me sing, you don't know whether it's true or false)
P2- false (I'm not singing now!)
structure- valid
overall- unsound (bad premises)

12) If Sean sings, then students cringe.
Sean isn't singing right now.
Students aren't cringing right now.

P1- questionable (again, you don't know)
P2- true
structure- invalid (from premise 1, we only know what happens when Sean is singing, not when he isn't singing; students could cringe for a different reason)
overall- unsound (bad 1st premise and structure)

13) If Sean sings, then students cringe.
Students aren't cringing right now.
Sean isn't singing right now.

P1- questionable (again, you don't know)
P2- true
structure- valid
overall- unsound (bad 1st premise)

14) If Sean sings, then students cringe.
Students are cringing right now.
Sean is singing right now.

P1- questionable (again, you don't know)
P2- false
structure- invalid (from premise 1, we only know that Sean singing is one way to guarantee that students cringe; just because they're cringing doesn't mean Sean's the one who caused it; again, students could cringe for a different reason)
overall- unsound (bad premises and structure)

Quiz You Once, Shame on Me

(Looking for the homework assignment? Click here!)

The first quiz will be held at the beginning of class on Monday, October 12th. You will have about 25 minutes to take it. There will be a multiple choice section, a section on evaluating deductive arguments, a section on evaluating arguments, and a section where you provide examples of specific kinds of arguments. Basically, it will look like a mix of the homework and group work we've done in class so far.

The quiz is on what we have discussed in class from Chapters 6, 8, and 7 of the textbook. Specifically, here's what will be covered on the quiz:

• definitions of: logic, reasoning, argument, structure, sound, valid, deductive, inductive
• understanding arguments
• evaluating arguments
  
• deductive args (valid & sound)
• inductive args

The quiz is worth 7.5% of your overall grade. Feel free to insult me in the comments for putting you through the terrible ordeal of taking a quiz.