Tired of the News? Try a Logic Quiz!
Hey, it's time to test your reasoning skills. The first exercise concerns hypothetical syllogisms. You may want to check out the logic tutorials to help you out. HAVE FUN!
I. Tell me if the following hypothetical syllogism is valid or invalid (does the argument work), and if the conclusion (#3) is true, false or uncertain. Why?
1. If Bush lied about WMD's being in Iraq, then no WMD's will be found in Iraq.
2. No WMD's were found in Iraq.
3. Therefore, Bush lied about WMD's in Iraq.
(hint: there are two ways to have a valid hypothetical syllogism: One, the causal connectionis #1 is true, and in #2: Affirm the __________, or deny the _________.) Stumped?
II. What fallacy is being used in the following argument and why doesn't the fallacy work?
1. At least 25 people mysteriously died because of their ties to Bill Clinton.
2. There's no proof to the contrary that they died of natural causes.
3. Therefore, these deaths are tied to Bill Clinton.
No matter what political stripe you wear, using this fallacy is not a proof.
III. Here's another one. It's tricky! Tell me if the argument is valid (does the argument actually prove the conclusion), and two, is the conclusion true, not true, or uncertain. Why?
1. All terrorist organizations kill innocent people.
2. The U.S. military kills innocent people.
3. Therefore, U.S. military is a terrorist organization.
IV. Finally, what fallacy is in this enthymeme (extra credit: can you state the missing premise):
1. 68% of Americans think President Bush is doing a poor job overall.
2. Therefore, President Bush is doing a poor job overall.
Good luck!!
posted by Underground Logician @ 1:02 PM
2 comments
2 Comments:
Okay, no takers.
For those of you who visit here but tremble in fear of commenting, let me assist you.
I. This type of hypothetical syllogism is a fallacy. It's a form of "modus ponens" or (method of affirming). BUT, it affirms the wrong part of #1, which has two parts. Behind the 'if', "Bush lied about WMD's being in Iraq" is called the antecedent; behind the "then" is the consequent. Modus ponens always affirms the antecedent; it would then affirm that Bush lied about WMD's. Therefore, there are no WMD's in Iraq. Makes sense, since Bush said that Iraq had them. If he lied, there will be no WMD's. Simple. However, the way I have it is assumed in public discourse to show that Bush lied. Why is it a fallacy. There can be more than one reason why there are no WMD's in Iraq, right? Bad intelligence, so Bush thought he was relaying truth, when he unwittingly gave false information. Or, Saddam could have destroyed the WMD's without telling anyone (why he would do so would be INCREDIBLY STUPID, given what was at stake to not reporting it. Or, Saddam moved them. However, in the first premise, for hypothetical to be true, it is necessary to prove that Bush lied to be true; the absence of WMD's is contingently true.
To prove the first premise false is modus tollens (method of denial). It denies the consequent. In this case the consequent is negative "no weapons were found." To deny this is to change it to a positive,"Weapons were found." Subsequently, Bush didn't lie. This particular formation is kind of sneaky and difficult to see at first. But, that's the world of sophistry for you.
II. This is a common fallacy of ad ignorantium (check the logic tutor). It states that because you cannot prove my statement false implies that it is true. This is used by conspiracy theorists on both sides of the aisle. It is taboo, future logicians!
III. This is quite common use of equivocation. Equivocation is the multiple use or definition or "nuance" of a term. In this case it is in the term "kill." If in fact our military intentionally kills innocents like terrorists do, then it would be a terrorist organization. If innocents are killed (collatorally, or unintentionally), then they would not be like terrorist organizations. This is why the charge that George Bush is the world's worst terrorist is so ludicrous. It's a rhetorical ploy not intended to give you needed information; it manipulates you to do what they want. Absolutely despicable!
IV. Finally, the hallowed polls. An enthymeme is an argument that is missing a key premise. They aren't bad in that sometimes they are used to abbreviate an argument, or that they determine something that is less than certain. However, sophists use them sneakily with presuppositions that are false at best, or incredibly stupid at worst. So in this example, the missing premise is, "Whatever the majority of Americans think is a poor job is the truth."
See how it works? Yeah, you get it.
An additional note to IV.
This enthymeme turns out to be an Ad Populum fallacy (to the people), where it tries to show that whatever the majority thinks is what is true. Majority opinion never makes something true; it simply shows what the majority thinks. So, if the majority thinks that the earth is flat...
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