Quiz

The quiz will be held at the beginning of class on Wednesday, September 30th. You'll have 25 minutes to take it, and it's worth 10% of your overall grade.

The quiz is on our tiny textbook (A Rulebook for Arguments). There will be a section on evaluating deductive arguments, and a section on evaluating the other kinds of arguments (example, analogy, authority, cause). Basically, the quiz will look a lot like the group work we've done in class so far.

Evaluating Deductive Arguments

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

1) All kangaroos are marsupials.
All marsupials are mammals.
All kangaroos 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 people are funny.
Sean is a person.
Sean is funny.

P1- true (we might disagree over who specifically is funny, but nearly all of us would agree that someone is funny)
P2- true (each "Sean" in this handout refers to your teacher, Sean Landis)
structure- invalid (the 1st premise only says some are funny; Sean could be one of the unfunny people)
overall- unsound (bad structure)

4) All email forwards are annoying.
Some email forwards are false.
Some annoying things are false.

P1- questionable ("annoying" is subjective)
P2- true
structure- valid (the premises establish that some email forwards are both annoying and false; so some annoying things [those forwards] are false)
overall - unsound (bad first premise)

5) All bats are mammals.
All bats have wings.
All mammals have wings.

P1- true
P2- true (if interpreted to mean "All bats are the sorts of creatures who have wings.") or false (if interpreted to mean "Each and every living bat has wings," since some bats are born without wings)
structure- invalid (we don't know anything about the relationship between mammals and winged creatures just from the fact that bats belong to each group)
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 Sean)
structure- valid
overall- unsound (bad premises)

8) All students in here are mammals.
All humans are mammals.
All students in here are humans.

P1- true
P2- true
structure- invalid (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 students in here are humans.
All humans are shorter than 10 feet tall.
All students in here are shorter than 10 feet tall.

P1- true
P2- true!
structure- valid (same structure as arg #1)
overall- sound

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
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- valid (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)

Correlatious

Here's yet another stick-figure comic (for those keeping track, that's five total on the blog so far). This one's about correlation.

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

Non-Deductive Arguments

Here are the answers to the group work we did in class on args by example, args by analogy, args from authority, and args about causes. Conclusions are in bold.

1. That Honus Wagner baseball card shouldn’t be that valuable. After all, it’s made out of cardboard, and cardboard boxes at Pathmark are super cheap.

Analogy
Bad - Material isn't always a relevant similarity to draw a conclusion about value: baseball cards are typically valued for their rarity, not what they're made of.

2. Canada, Mexico, USA, India, and Australia are all countries that border oceans on the east and west. Hence, most countries border oceans on both the east and west.

Example
Bad - 5 countries out of about 200 total nations is too small a sample. Also, the examples are cherry-picked, and so they're unrepresentative.

3. In a recent study, 100% of those who took a new birth control pill didn’t get pregnant. Only males participated in the study. Thus, the birth control pill must be very effective.

Cause
Bad - A better explanation of the correlation between taking the pill and not getting pregnant is that males don't get pregnant.

4. Oasis sounds just like The Beatles. We all know that The Beatles were one of the most influential rock bands ever. So Oasis must be one of the most influential bands, too.

Analogy
Bad - A similar sound isn't a relevant enough similarity regarding whether a band is influential.

5. Abortion is morally acceptable because renowned linguist Noam Chomsky has defended the practice of abortion, and he’s pretty smart.

Authority
Bad - Chomsky's expertise (linguistics) isn't relevant to the topic of abortion.
(Chomsky explains his view on abortion in the video to the right.)

6. Most people say the money it costs to go to law school is worth it, because lawyers earn a lot of money. So, since doctors also earn a lot, med school costs must be worth it, too.

Analogy
Pretty Good - The similarity (average money earned per profession) is relevant to whether med school is financially worth it. Assuming one thinks a large up-front investment is worth an even larger salary in the future, this arg is good.

7. My friend knows me better than anyone else, and he says I’m a decent guy. Therefore, I must be a decent guy.

Authority
Bad - Yes, my friend is a relevant expert, but he's likely to be biased in favor of me since he is my friend.

8. My sis usually keeps her car windows rolled down, though she always rolls them up right before it rains. Her car must be magical, then: rolling up her windows causes it to rain.

Cause
Bad - This is reversed! The rain probably causes her to roll up her window, not the other way around.

9. This guitar-shaped flyswatter costs $2 more than that normal one. Most of the expensive stuff I’ve bought in the past turned out to be higher quality than similar, cheaper items. Hence, the guitar-shaped swatter is higher quality than the normal one.

Example
Bad - While there may be a general correlation between expense and quality, it is not representative of this kind of novelty item. There is also a correlation between price and novelty: the more unique an object is, the more expensive it typically is.

10. Nearly every time I see Conan O’Brien on television, I wind up falling asleep. Thus, I guess Conan puts me to sleep.
Cause
Bad - Another way to explain this correlation between Conan and my sleep is the fact that his shows have been on late at night, a time at which I'm usually tired anyway.

How Myths Spread

Check the Source

-via GraphJam

An Expert for Every Cause

Looking for links on arguments from authority? This is your post! First, here's an interesting article on a great question: How are those of us who aren't experts supposed to figure out the truth about stuff that requires expertise?

Not all alleged experts are actual experts. Here's a method to tell which experts are phonies (this article was originally published in the Chronicle of Higher Education).

It's important to check whether the person making an appeal to authority really knows who the authority is. That's why we should beware of claims that begin with "Studies show..."

And here's a Saturday Night Live sketch in which Christopher Walken completely flunks the competence test.

Philosophers In Their Own Words

Photographer Steve Pyke has a cool series of portraits of philosophers. Many of the philosophers also provide a short explanation of their understanding of what it is they do. Here are a few of my favorites:

Delia Graff Fara:

"By doing philosophy we can discover eternal and mind independent truths about the ’real’ nature of the world by investigating our own conceptions of it, and by subjecting our most commonly or firmly held beliefs to what would otherwise be perversely strict scrutiny."

Kit Fine:

"Philosophy is the strangest of subjects: it aims at rigour and yet is unable to establish any results; it attempts to deal with the most profound questions and yet constantly finds itself preoccupied with the trivialities of language; and it claims to be of great relevance to rational enquiry and the conduct of our life and yet is almost completely ignored. But perhaps what is strangest of all is the passion and intensity with which it is pursued by those who have fallen in its grip."

Sally Haslanger:

"Given the amount of suffering and injustice in the world, I flip-flop between thinking that doing philosophy is a complete luxury and that it is an absolute necessity. The idea that it is something in between strikes me as a dodge. So I do it in the hope that it is a contribution, and with the fear that I’m just being self-indulgent. I suppose these are the moral risks life is made of."

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.

Arguments by Example

Here are a few dumb things about arguments by example (also called inductive arguments, talked about in the book chapter titled "Generalizations"). First, a video of comedian Lewis Black describing his failure to learn from experience every year around Halloween:


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

The Full Moon Myth?

Scientific American has a nice article examining the widely-held belief that the full moon causes strange behavior. Research suggests the full moon doesn't have this effect:

"By combining the results of multiple studies and treating them as though they were one huge study—a statistical procedure called meta-analysis—[scientists] have found that full moons are entirely unrelated to a host of events, including crimes, suicides, psychiatric problems and crisis center calls. In their 1985 review of 37 studies entitled 'Much Ado about the Full Moon,' which appeared in one of psychology’s premier journals, Psychological Bulletin, Rotton and Kelly humorously bid adieu to the full-moon effect and concluded that further research on it was unnecessary."

One reason the belief persists is a set of natural human cognitive biases in which we perceive correlations where no such correlations exist:

"Illusory correlations result in part from our mind’s propensity to attend to—and recall—most events better than nonevents. When there is a full moon and something decidedly odd happens, we usually notice it, tell others about it and remember it. We do so because such co-occurrences fit with our preconceptions. ... In contrast, when there is a full moon and nothing odd happens, this nonevent quickly fades from our memory. As a result of our selective recall, we erroneously perceive an association between full moons and myriad bizarre events."

We'll be discussing these biases more when we study arguments about causes. Here's a cool video by psychological Dan Gilbert on our mistaken expectations:

Understanding Arguments

Here are the answers to the handout on understanding shorter arguments that was assigned as optional extra credit.

1. (P1) Fairdale has the best team.
(C) Fairdale will win the championship

2. (P1) The housing market is depressed.
(P2) Interest rates are low.
(C) It's a good time to buy a home.

3. (P1) China is guilty of extreme human rights abuses.
(P2) China refuses to implement democratic reforms.
(C) The U.S. should refuse to deal with the present Chinese government.

4. (P1) The results of the Persian Gulf War were obviously successful for the U.S. military.
(C) The U. S. military is both capable and competent.

5. (P1) The past 3 women's U.S. tennis champions have changed to Wilson's new line of rackets.
(C) It's time to trade your racket in for a Wilson racket.

6. (P1) My doc said she'd be performing a blood test on me when I visit her today.
(C) I know I'll feel pain today.

7. (P1) Most of those who enjoy music play a musical instrument.
(C) If Maria enjoys music, she probably plays a musical instrument.

8. (P1) I'm very good at my job.
(C) I deserve a raise.

9. (P1) Jesse is one year old.
(P2) Most one-year-olds can walk.
(C) Jesse can walk.

10. (P1) The revocation of the 55 mph speed limit has resulted in an increased number of auto fatalities.
(C) we must alleviate this problem with stricter speed limit enforcement.

11. (P1) The last person we hired from Bayview Tech turned out to be a bad employee.
(C) I'm not willing to hire anybody else from that school again.

12. (P1) Maebe didn't show up for work today.
(P2) Maebe has never missed work unless she was sick.
(C) Maebe is probably sick today.

13.(P1) There are no pesticide controls in this county.
(C) There are no edible fish in the streams of this county.


14.(P1) This city's beautiful beaches are the most overcrowded beaches in the state.
(C) Beautiful beaches definitely attract people.

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Hat tip: I took some of the examples (with some revisions) from Beth Rosdatter's website , and some (with some revisions) from Jon Young's website .

Trying to Get Away Into the Night

If only everything were as wholesome as '80's era Tiffany videos:

Club Meeting

I'm the adviser for a school club called "Owning Our Ignorance" that's devoted to improving our learning through fun and reasoning. You know, nerdy cool stuff.

We're having our first meeting of the semester this Thursday at 1:00 p.m. in Madison 103. More info on the meeting is available here. More info on the club is available here.

If you're interested, come on out!

Philosophy: The Nagging 3 Year Old

Here's comedian Louis CK's take on the broad, fundamental questions kids ask.

Louis CK - Why?

Email Subscription

So why does this course have a blog? Well, why is anything anything?

A blog (short for “web log”) is a website that works like a journal – users write posts that are sorted by date based on when they were written. You can find important course information (like assignments, due dates, reading schedules, etc.) on the blog. I’ll also be updating the blog throughout the semester, posting interesting items related to the stuff we’re currently discussing in class. You don't have to visit the blog if you don't want to. It's just a helpful resource. I've used a blog for this course a lot, and it's seemed helpful. Hopefully it can benefit our course, too.

Since I’ll be updating the blog a lot throughout the semester, you should check it frequently. There are, however, some convenient ways to do this without simply going to the blog each day. The best way to do this is by getting an email subscription, so any new blog post I write automatically gets emailed to you. (You can also subscribe to the rss feed, if you know what that means.) To get an email subscription:

1. Go t0 http://2010cccphilosophy.blogspot.com.

2. At the main page, enter your email address at the top of the right column (under “EMAIL SUBSCRIPTION: Enter your Email”) and click the "Subscribe me!" button.

3. This will take you to a new page. Follow the directions under #2, where it says “To help stop spam, please type the text here that you see in the image below. Visually impaired or blind users should contact support by email.” Once you type the text, click the "Subscribe me!" button again.

4. You'll then get an email regarding the blog subscription. (Check your spam folder if you haven’t received an email after a day.) You have to confirm your registration. Do so by clicking on the "Click here to activate your account" link in the email you receive.

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If you are unsure whether you've subscribed, ask me (609-980-8367; slandis@camdencc.edu). I can check who's subscribed and who hasn't.