Disproving Claims and Critical Evaluations
I. Given the approach to understanding, and reconstructing arguments we have learned in this course, we can now consider how arguments go wrong, or fail in their efforts to convince an audience to accept the conclusion. That is, the point of an argument is to get an audience to accept the conclusion. And we have learned that arguments have logical form: they are either deductively valid, inductively cogent, or they are ill-formed.
Put simply, an argument is either going to be faulty because it has bad logical form (it is ill-formed), or it has premises that are false or that the audience suspends judgment on.
Put another way, when we critically evaluate an argument, we determine whether or not it is a strong (deductively or inductively) argument.
In order to be strong, an argument must be well-formed (valid or cogent)
AND
The premises must be reasonable for you to believe.
So if you are going to reject an argument there are only two ways to offer a refutation. Either show that it is ill-formed, of argue that one or more of the premises are false:
Show that the argument is ill- formed. That is, show that it is neither valid nor cogent.
Example: Smith says:
1. Every politician in Washington is taking money from special interest groups.
2. John is taking money from special interest groups.
______________________________
3. Therefore, John is a politician in Washington.
Refutation: The argument is ill-formed. Valid arguments are arguments where, the premises, if they were true, would guarantee the truth of the conclusion. In this argument, even if the premises were true, it wouldn't guarantee the truth of the conclusion. Cogent arguments are invalid, and the premises, if they were true, would make the conclusion likely to be true. These premises, even if they were truth, don't make the conclusion likely to be true. There is nothing in the information provided that suggests that most people who take money from special interest groups are in in Washington. So this argument isn't cogent either. That is, the premises just don't give support to the conclusion. To illustrate how an argument is ill-formed, you can give an example where the premises are true, but the conclusion is not true or likely to be true to show the failure of support. Or you can give an example of an argument with the same logical structure but where it's obvious that the premises support the conclusion:
1. All mammals reproduce. (true)
2. Bacteria reproduce. (true)
__________________________
3. Therefore, bacteria are mammals. (false)
Or,
All people in Washington are in the United States.
Tom Cruise is in the United States.
_______________________________
Therefore, Tom Cruise is in Washington.
In both cases, it's clear that the premises, even when they are true, don't support the conclusion or give us grounds to believe it is true. So the original argument fails because of its poor logical structure.
Argue that one or more of the premises are false. (if you suspend judgment then the argument will also be weak, but merely suspending judgment is not a very strong criticism of an argument.) How do you argue that one or more of the premises are false? Quite often, people will seem to be objecting or disagreeing with an argument or a point that is being made, but the objection they are offering doesn't actually undermine it. Recall in the beginning of the semester, we learned about logical consistency. Two claims are logically consistent if it is possible for both of them to be true at the same time. If an objection to an argument asserts a claim that is logically consistent with the conclusion, then that objection isn't actually an objection at all. Consider this example:
Smith says, "Running a red light is breaking the law."
Jones objects, "Not necessarily, going 20 mph over the speed limit is breaking the law too."
Notice that what Jones has said is logically consistent with what Smith said. Both claims are, in fact, true. Jones seems to have misunderstood Smith as saying, "Only running a red light breaks the law, and nothing else." Jones' objection would be logically inconsistent with this new claim, but Smith didn't assert it, so they aren't actually disagreeing and Jones has failed to give us any reason to doubt what Smith has said. If Smith had asserted "only running a red light breaks the law," it would be mistaken, and Jones' objection would have worked. But Smith can rightfully defend herself and say, "I didn't say that ONLY running a red light breaks the law, I just said that it's one way the law gets broken." By taking care to express the claim in the right logical form, Smith says something that is true and that resists the objection.
The point here, then, is that in order to successfully object to an argument, or to critically reply to an assertion, we will need to be very clear about what is being claimed in the argument, and then the objection should address those claims (or the logical structure) of the argument directly and specifically. Vague, non-specific, or logically consistent objections aren't objections at all, and they don't give the audience any grounds for rejecting the argument in question.
II. What does it take to disprove a claim?
Let's consider some general forms of sentences and what sort of objection would or would not succeed as a criticism of them. Consider sentences of the form:
1. All As are Bs.
In order to disprove an “All As are Bs,” claim, we only need to find a single example of an A that is not a B. But often, people's objections to these sorts of claims are confused and logically consistent:
Claim: All trees are deciduous.
Disproof: Redwoods are trees that are not deciduous.
Mistake: A very common mistake is to give examples of some Bs that are not As.
Here are some more pseudo-objections to sentences of this form:
Jones says, "All birds lay eggs."
Smith says, “I think you must be mistaken. There are some sea animals that lay eggs.”
Jones says, “But you’re not understanding my claim. I said, ‘All birds lay eggs.’
What is Smith’s confusion about Jones’ ‘All As are Bs’ claim? It appears that Smith thinks Jones said, "All and only birds lay eggs." or "The only animals that lay eggs are birds." If Smith had said either of those, then the objection would work. But sentences of the form "All As are Bs," logically do not imply that "All Bs are As." Consider: "All bears are mammals" does not imply that "All mammals are bears."
Here's another example of an objection that misses the mark:
A Marine biologist says: “All sea mammals have a protective layer of blubber.”
Critic: “But hippos have a protective layer of blubber.”
Professor: “All faculty members are going on strike.”
Student: “But that can’t be right. The janitorial staff are not going on strike.”
Claim: “All mammals are warm blooded.”
Objection: “No, that’s incorrect. When reptiles lay out in the sun, their blood becomes warm. And many paleontologists have concluded that the dinosaurs were warm blooded.”
In all of these cases, the objector asserts a claim that is logically consistent, so it's not an objection at all. In general, for claims of the form "All As are Bs," objections are simple. The critic only needs to find a counter example to the general claim: a single case of an A that is not a B. And only that sort of example will refute the assertion.
So "All capitols of American states are on major intersections of rivers." is successfully refuted, at least in form, by "Des Moines is a capitol of an American city that is not on a major intersection of rivers."
2. Most As are Bs. What about claims like this that make an assertion about what is usually the case or what's true for most members of a class?
“Most CSU faculty members are in favor of striking to resolve the contract dispute.”
Which of these would disprove the claim?
“Smith is a CSU faculty member who is not in favor of striking to resolve the contract dispute.”
“All of the CSU faculty members in the Sacramento biology department are not in favor or striking to resolve the contract dispute.”
“None of the CSU faculty members at the Long Beach, Chico, Dominguez Hills, and San Bernardino campuses favor the strike, and together they all make up 54% of the CSU faculty total.”
“All of the CSU faculty at the Sacramento, Los Angeles, and San Diego campuses are opposed to the strike and they make up 35% of the total CSU faculty.”
In general, “most As are Bs,” claims can be the hardest to disprove because we need to gather evidence that shows that in fact a minority of As are Bs, or that Most As are not Bs.
So if a poll says, “most Americans approve of GWB’s performance.” Then the only way to disprove, or at least challenge the claim would be to conduct a poll that has the results that most Americans do not approve of GWB’s performance.
But then we would have to figure out which one to accept. What would make one better than another?
3. X is an A. What about simple assertions that something has a property?
a. Arnold did not use steroids.
b. Attorney General Gonzales did not fire the 8 subordinate attorneys.
c. GWB did not know that there were no weapons of mass destruction in Iraq before the war.
d. Echinacea cures colds.
What would disprove these sorts of claims? Evidence that makes it compelling that X is not an A.
a. Compelling evidence that Arnold did use steroids.
b. Emails, video tape, recordings, letters from the AG that indicate that it was his decision to fire the attorneys.
c. Documentation that GWB did know: reports filed to the president, the president’s signature on documents that say there are no WMDs.
d. Evidence that shows that the rate of colds is the same for echinacea users as for non users.
4. If P then Q. In general, what would disprove a conditional claim. What a conditional asserts is that if P occurs, then Q follows. So the only sorts of circumstances that would disprove a conditional are cases where the antecedent is true and the consequent is false.
a. If you are in Congress, then you are a man.
Disproof: Nancy Pelosi is in Congress, but she is not a man.
b. If you are a woman, then you are not good at science.
Disproof: A real case of a woman who is good at science.
Not disproof: A man who is bad at science.
c. If you are rich, then you must manage your money well.
Disproof: Someone who is rich—Paris Hilton—who does not manage their money well.
Not disproof: Someone who manages their money well, but who is not rich.
d. If you are Asian, then you are a bad driver.
Disproof: An Asian who is not a bad driver.
Not disproof: A non-Asian who is a bad driver.
e. If you are good at critical thinking, then you must be a man.
Disproof: A non-man who is good at critical thinking.
f. If Mike goes to the store, then he will take the truck.
Disproof: Mike goes to the store without the truck
g. If it is raining, then McCormick will drive rather than ride his bike.
Disproof: McCormick riding his bike in the rain.
h. If the flag is up on the boathouse, then there is dangerous weather out on the lake.
Disproof: A case where the flag is up but there is good (non-dangerous) weather out on the lake.
Not disproof: The flag is down (not up), and there is dangerous weather out on the lake.
5. No As are Bs. What would disprove the claim that nothing in the class A is also a B? Logically, disproof is simple here. We just need a single case of an A that is a B.
a. No animals with hair have beaks.
Disproof: Duckbill platypus. An animal with hair and a beak.
Not disproof: An animal with a beak, like a chicken, without hair.
b. No congressmen are corrupt.
Disproof: A corrupt congressman. Sen. Bill Frist—insider trading.
Not disproof: A corrupt person, like Kenneth Lay, former CEO of Enron.
c. No presidents get confused.
Disproof: Ronald Reagan. Reagan was not in WWII, but he played in WWII movie roles. He would sometimes tell stories about WWII that were from the movie as if he had fought.
Not Disproof: A president who does not get confused.
d. No white people can rap.
Disproof: Eminem. A white person who can rap.
Not disproof: A non-white person who cannot rap. The sentence does not say that all black people can rap, or that all non-white people can rap, only that no white people can.
The disproof, in every case, is giving an instance where something has both properties in question:
6. All As are X or Y.
Disproof: A case of an A that is neither X nor Y.
Claim: “All American political candidates are either Democrats or Republicans.
Disproof: Ralph Nader is an American political candidate who is Green, neither Democrat nor Republican.
So now we've seen that to successfully object to an argument, the critic must be clear about what conclusion is being argued for, and the critic must give reasons to either believe that the argument is ill-formed: it's logical structure doesn't support the conclusion, or some of the claims given in support of the conclusion, the premises, are false or doubtful. And now we've seen several ways to take a specific claim, like a premise, and how to give an objection that undermines it directly and specifically. If we have reasons to think that an argument is ill formed, or if we doubt the premises or if we believe a premise(s) are false, then the argument is weak, as we learned in earlier weeks.
III. Common Mistakes in Argument Evaluation: there are a number of common mistakes that people make when objecting to arguments:
1. Don’t criticize an argument by denying its conclusion.
2. Don’t accept an argument simply because you agree with the conclusion.
1. All politicians are habitual liars.
2. Bill Clinton is a politician.
3. Therefore, BC is a liar.
3. Direct Criticisms at Individual premises.
An argument can really only have problems with its logical form, or the content of one or more of the premises. So if you are criticizing the premises, you need to say which ones are false or unreasonable and explain why you think so. There cannot be general problems with an argument like “It’s not a reasonable argument,” or “It’s not put together well.”
4. Make your criticisms of premises substantial.
a. “Just because fallacy.” It’s very common for people to respond to arguments that they have doubts about by saying “just because. . . . “
Example 1:
Argument: You cannot really know anything because if you can be wrong about anything, then you cannot know it. And you can be wrong about anything you believe.
Response: Just because you can be wrong about something doesn’t necessarily mean you can’t know it.
Problem: This response denies one of the premises of the argument: “If you can be wrong about something then you cannot know it.” But it gives us no reasons, no evidence, no argument for why we should accept the counter claim instead of the argument.
These responses amount to just saying, “Nuh-uh.” And not much more.
Example 2:
Argument: If it was possible to prove that God exists, then people would have been able to do it by now. So, I don’t think it is possible.
Response: Just because people haven’t proven it by now doesn’t mean they won’t.
Again, this is an empty, unconvincing response. The critic gives us no reasons for accepting the rejection over the premise in the argument.
If the author makes claims that seems unreasonable, it is not sufficient to say “Maybe X is not true.” Or “X is not guaranteed to true.” If the author says All As are Bs, it isn’t adequate to criticize the claim to say that maybe some As are not Bs.
The explanation that you have given is not adequate to show that the claim is doubtful or unreasonable, you have merely pointed something that is almost always true, that maybe it could be wrong. But no one will conclude that they shouldn’t believe it because of that possibility alone. The job of an objection is in effect to give another argument for a different conclusion, or for the conclusion that the conclusion of the argument is unreasonable. So there is a substantial burden of proof on the criticizer to justify why the conclusion is not reasonable to believe on the grounds of the premises.
b. Avoid Argument Stoppers:
“Who’s to say that that’s true?”
“Where do you draw the line between this and that?”
“That’s just a matter of opinion,”
“That’s just your opinion,”
“That’s a subjective judgment,”
“Everyone is entitled to their opinion.”
These responses are empty, pointless, and shut down any rational inquiry into possibly important topics. Imagine someone is trying to decide whether or not it morally acceptable to get an abortion:
Argument 1:
1. People can do what they want to with their own bodies.
2. Getting an abortion is something that a pregnant woman can with her body.
___________________________
3. Therefore, a pregnant woman can get an abortion.
Response: ”Everyone is entitled to their opinion.”
Or
“That’s a subjective judgment.”
Argument 2:
1. Anything that will help lower violence in the our cities is justified.
2. Increasing our police forces will help lower violence in our cities.
__________________________________
3. Therefore, increasing our police forces is justified.
Response:
“Who’s to say that’s true?”
“Where do you draw the line between what is justified and what is not?”
Argument 3:
1. The military should be able to do anything it needs to in order to win the war on terrorism.
2. Killing civilian bystanders is something it needs to do in order to win the war on terrorism.
____________________________________________
3. Therefore, the military should be able to kill innocent bystanders.
Argument 4:
1. Americans’ safety at home must be assured at all costs.
2. Some of our civil liberties need to be compromised in order to be safe.
__________________________________
3. Therefore, some of our civil liberties need to be compromised.
Consider some more examples of bad objections, many of them taken from students' responses in the Strength Homework.
The purpose of an objection O to a claim P is to offer grounds that would give us reasons to doubt the truth of P, disbelieve it, or at least suspend judgment about it. So the question to ask when we are considering an objection to a claim is: Does O, if true, give me any reason to doubt that P is true? If the answer is no, then it is not a good objection.
Consider these pairs of sentences. The first is an assertion, the second is a bad objection to it. What is wrong with these objections? Why don’t they work? What would be a better objection to the claim?
A. Claim: Most of the time when people give testimony about extraordinary and important things, like seeing Bigfoot, that they have seen they don't lie.
Objection 1: But people do lie.
Objection 2: Many people lie about Bigfoot.
Objection 3: I know someone who lied about Bigfoot.
(Objection 1 is consistent with the claim. It could be true that most people don’t lie but some do. So the objection doesn’t give us any grounds for disbelieving the claim.)
(Objection 2 is also consistent with the claim. Most could be telling the truth while many are lying.)
(Objection 3 is also irrelevant to the claim. Most of the Bigfoot testifiers are telling the truth is consistent with one person lying.)
B. Claim: If a person wants to be happy, then they should pursue a stable, married relationship.
Objection: My aunt is in a stable, married relationship, but she’s not happy at all.
(In a conditional of the form If P then Q, the only sort of case that would disprove it is a case where P occurs but Q does not. It must be a case where the antecedent is truth but the consequent is false. For this case, it would require a person who wants to be happy, but they shouldn’t pursue a stable, married relationship. Your unhappily married aunt is irrelevant.)
C. Argument:
1. Most of the time when people give testimony about extraordinary and important things that they have seen they don't lie.
2. People give testimony about Bigfoot, which is an extraordinay and important thing that they have seen.
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3. Therefore, people are not lying about seeing Bigfoot.
Objection: I don’t know if Bigfoot really exists or not.
(The objection is vague. It’s not directed at any premise really. It doesn’t give us grounds to deny any of the premises. It sort of expresses doubts about the conclusion. But ironically, this argument has just given you grounds for thinking that Bigfoot exists. So why doubt it?)
D. Claim: All people who have the capacity to kill should avoid having loaded guns around the house.
Objection: Every person has the capacity to kill, but not everyone kills.
(The objection seems relevant, but it doesn’t deny what the claim asserts. It might be suggesting that even though everyone has the capacity, some don’t act on it. So perhaps it’s ok for them to keep guns around the house. But the claim still sounds like sound advice, and the objection doesn’t give substantial reason to dobut it.)
E. Claim: Most of the pop music stars who become popular very quickly and disappear fast are not talented
Objection 1: Lady GaGa has no talent, and she hasn’t disappeared.
Objection 2: Many talented pop-stars have disappeared, but it doesn’t mean that they weren’t talented.
Objection 3: John Mayer is very talented and he became popular very quickly and he didn’t disappear.
(None of these are relevant, nor do they disprove the claim.)
F. Claim: The state legislature needs to pass a budget to prevent wasting more money that the state doesn’t have.
Objection: This is based on an assumption, not facts.
(The objection seems to be that the claim isn’t well founded, but it doesn’t give any reason to doubt the claim. What’s wrong with assumptions, anyway? If they are correct, then why not make them? I am assuming that the reader of this page is a reasonable person. Is that a mistake?)
G. There is evil in the world
Objection: The concept of evil varies from person to person. What one may view as good another may view as evil.
Consider a parallel claim and assertion:
Claim: There are camels.
Objection: The concept of what a camel is may vary from person to person. One might view a thing as a camel while another might think that is a dog.
(The objection, even if it is true, is irrelevant to the claim. If there are people who think that camels are dogs they’d just be wrong about that. Their confusion or any controversy there might be about what evil is doesn’t give us any grounds to think that there is no such thing. Besides, people’s views about what actions are evil actually don’t vary that much.)