This is a Flaw/Descriptive Weakening question.

The stimulus starts with a claim from many prominent physicists. So that’s OPP. They claim that energy is merely a theoretical construct. Next, the author gives a premise, that the theory of relativity tells us that there is no essential distinction between energy and mass, and draws an intermediate conclusion, that mass must also be a theoretical construct.

First, note that the author uses OPP to further her own argument. This is uncommon. Usually, when OPP is present, the author challenges it.

Next, let’s examine the reasoning in this sub-argument before moving on to the main argument. How strong is the support? Well, the two premises both rely on authority to establish the truth of their claims. The first premise relies upon the authority of “many prominent physicists.” The second premise relies upon the authority of the theory of relativity. When it comes to appeals to authority, the key question to ask is if the appeal is to relevant authority. If it isn’t, then that’s a flaw. Here, the appeals are to relevant authority. First to “many prominent physicists” on what energy is and second to the “theory of relativity” on the relationship between mass and energy. Does that mean the sub-conclusion is validly drawn? No. Arguments that rely on appeals to relevant authority are never valid. But they can be reasonable. This sub-conclusion, mass is a theoretical construct, is reasonable. We can weaken the argument and we can strengthen the argument.

The main argument proceeds to use this sub-conclusion as a major premise. It also supplies another major premise, that all physical objects are composed purely of mass and energy. From those two premises, the conclusion is drawn that physical objects must also be theoretical constructs.

Now let’s examine the reasoning in this main argument. Do you recognize the pattern? It’s a part-to-whole argument. One premise states that mass (and energy) has a certain characteristic (being a theoretical construct). Another premise states that physical objects (whole) are composed purely of mass and energy (parts). The conclusion attributes the characteristic of the parts to the whole.

This is what Correct Answer Choice (B) points out. It says that the argument overlooks the possibility that something (a physical object, the “whole”) may lack a feature (being a theoretical construct) even if it (a physical object) is composed purely of things (mass and energy, the “parts”) that have that feature (being a theoretical construct). That’s exactly right.

Answer Choice (A) says the argument fails to consider whether anything other than physical objects may be composed purely of mass and energy. That’s true, the argument didn’t consider this. Do mass and energy together make up other, non-physical object things? But, wait, it doesn’t matter. Whether the answer is yes or no has no bearing on why the argument is vulnerable to criticism.

Answer Choice (C) says the argument presumes without justification that two things may have different features even if there’s no essential distinction between them. But that’s descriptively inaccurate. The argument actually presumes the opposite. It presumes that two things (mass and energy) cannot have different features if there’s no essential distinction between them. That’s how it drew the intermediate conclusion that mass is also a theoretical construct.

Answer Choice (D) says that the argument fails to adequately address the possibility that features of some theoretical construct need not be shared by every theoretical construct. The argument didn’t address this but it didn’t need to. (D) thinks “theoretical construct” has a “feature,” but in the argument, “theoretical construct” is itself the “feature.” In the argument, “theoretical construct” is the feature of energy and it’s also the feature of mass. We can map (D)’s “theoretical features” onto “mass” and “energy” in the argument, but then we’d have nothing to map (D)’s “features” onto.

Answer Choice (E) says the argument presumes, without providing justification, that the fact that a suggestion has been made by a physicist proves the truth of that suggestion. This is the most attractive wrong answer. (E) targets the reasoning in the sub-argument. Specifically, (E) recognizes that the reasoning there relied on an appeal to authority. This is good. But where (E) missteps is in failing to recognize that the appeal is to (many) relevant authorities. (E) thinks the argument “presumes, without providing justification” that just because “a physicist” made a suggestion, the suggestion is true. But in reality, the argument “presumes, with justification” that because “many prominent physicists” made a suggestion, the suggestion is true. The former would be a glaring vulnerability. The latter, while not ironclad, is much less of a vulnerability. The former is not equivalent to the latter, and therefore (E) is descriptively inaccurate.

10 comments

This is a Flaw/Descriptive Weakening question.

The argument takes on a form that we’ve seen plenty before. It says that the Swahili civilization built a particular kind of tomb. Such tombs were widespread among the Oromo civilization and unknown among any other civilization that the Swahili had contacted. From these premises, the argument draws the conclusion that the Swahili were influenced by the Oromo.

Okay, that’s a bold assertion on thin evidence. All we know is that the Oromo also built these tombs. That doesn’t mean that the Swahili imitated the Oromo. It’s certainly possible. But it’s also possible that the Oromo imitated the Swahili. That’s an alternative hypothesis. To discriminate between them, we need more information. Maybe there’s some evidence consistent with one hypothesis but inconsistent with the other. Maybe there’s information about chronology. Who built these tombs first? That’d be a clue about who’s the influencer and who’s the imitator.

Answer Choice (A) says that the argument fails to adequately address the possibility that the Oromo used these structures as something other than tombs. That’s true. But that’s not where the argument is weak. Even if we stipulate that the Oromo used these structures as tombs, the argument still suffers from its causal weaknesses.

Answer Choice (B) says that the argument concludes that the first event caused the second event simply because the first event occurred earlier. If only! Information about the Oromo being first to build these tombs would be really helpful in establishing the conclusion that the Swahili learned from the Oromo. There is no such information so (B) is descriptively inaccurate.

Answer Choice (C) says that the argument draws a restricted conclusion from premises that provide strong support for a much broader conclusion. Uh, come again? (C) thinks this argument could have drawn a broader conclusion? And that the main weakness of the reasoning is that the actual conclusion didn’t go far enough? That’s crazy. The argument has a hard enough time supporting its existing conclusion. It won’t be helped if we swap that conclusion out for an even heavier, more expansive conclusion. I think (C) is picking up on the “to some extent” qualifier in the conclusion. Like, (C) is saying that’s what makes the argument vulnerable, that it should have just come out with a more forceful conclusion. But that misses the point. Toggling the strength of the causal arrow up or down is irrelevant. The problem with this argument is that the causal hypothesis in the conclusion is merely one of many.

Answer Choice (D) says that the argument assumes there was no third civilization responsible for creating the first tombs of the kind found in both the Oromo and Swahili cultures. This is a very attractive trap. It describes a cookie-cutter flaw that we’ve seen so many times in other Flaw questions. The problem is that the argument doesn’t make this assumption. The premises already established that the Swahili had no contact with any other civilization that built such tombs. That precludes the hypothesis that a third civilization was the true creators of these tombs and they were the OG influencers. That couldn’t have happened because the Swahili had no contact with any other civilization that built these tombs except the Oromo. Since this third culture hypothesis is already precluded, the argument doesn’t have to assume anything about whether they first created these tombs. It wouldn’t matter either way. Imagine if it were true that some third culture created the tombs. So what? They’re halfway across the continent and the Swahili didn’t have any contact with them. So if the Swahili learned it from anyone, it would still have to be from the Oromo. (D) is descriptively inaccurate. The argument makes no such assumption because the argument doesn’t have to. The alternative hypothesis that (D) is concerned with was already precluded by the premises.

Correct Answer Choice (E) says that the argument assumes that the Oromo built their tombs earlier than the Swahili did. Yes, that’s definitely an assumption that the argument makes. In order for the Oromo to have influenced the Swahili, the Oromo had to have done it first. If the Swahili got there first, then perhaps it’s the Oromo who were influenced by the Swahili. (E) is descriptively accurate. More than that, (E) is why the argument is weak. There is no information about who got there first. Without that information, we cannot say whether the Oromo as influencer hypothesis or the Swahili as influencer hypothesis is more likely to be true. This is precisely where the argument is most vulnerable to criticism.

1 comment

This is a Flaw/Descriptive Weakening question.

The argument takes on a form that we’ve seen plenty before. It says that the Swahili civilization built a particular kind of tomb. Such tombs were widespread among the Oromo civilization and unknown among any other civilization that the Swahili had contacted. From these premises, the argument draws the conclusion that the Swahili were influenced by the Oromo.

Okay, that’s a bold assertion on thin evidence. All we know is that the Oromo also built these tombs. That doesn’t mean that the Swahili imitated the Oromo. It’s certainly possible. But it’s also possible that the Oromo imitated the Swahili. That’s an alternative hypothesis. To discriminate between them, we need more information. Maybe there’s some evidence consistent with one hypothesis but inconsistent with the other. Maybe there’s information about chronology. Who built these tombs first? That’d be a clue about who’s the influencer and who’s the imitator.

Answer Choice (A) says that the argument fails to adequately address the possibility that the Oromo used these structures as something other than tombs. That’s true. But that’s not where the argument is weak. Even if we stipulate that the Oromo used these structures as tombs, the argument still suffers from its causal weaknesses.

Answer Choice (B) says that the argument concludes that the first event caused the second event simply because the first event occurred earlier. If only! Information about the Oromo being first to build these tombs would be really helpful in establishing the conclusion that the Swahili learned from the Oromo. There is no such information so (B) is descriptively inaccurate.

Answer Choice (C) says that the argument draws a restricted conclusion from premises that provide strong support for a much broader conclusion. Uh, come again? (C) thinks this argument could have drawn a broader conclusion? And that the main weakness of the reasoning is that the actual conclusion didn’t go far enough? That’s crazy. The argument has a hard enough time supporting its existing conclusion. It won’t be helped if we swap that conclusion out for an even heavier, more expansive conclusion. I think (C) is picking up on the “to some extent” qualifier in the conclusion. Like, (C) is saying that’s what makes the argument vulnerable, that it should have just come out with a more forceful conclusion. But that misses the point. Toggling the strength of the causal arrow up or down is irrelevant. The problem with this argument is that the causal hypothesis in the conclusion is merely one of many.

Answer Choice (D) says that the argument assumes there was no third civilization responsible for creating the first tombs of the kind found in both the Oromo and Swahili cultures. This is a very attractive trap. It describes a cookie-cutter flaw that we’ve seen so many times in other Flaw questions. The problem is that the argument doesn’t make this assumption. The premises already established that the Swahili had no contact with any other civilization that built such tombs. That precludes the hypothesis that a third civilization was the true creators of these tombs and they were the OG influencers. That couldn’t have happened because the Swahili had no contact with any other civilization that built these tombs except the Oromo. Since this third culture hypothesis is already precluded, the argument doesn’t have to assume anything about whether they first created these tombs. It wouldn’t matter either way. Imagine if it were true that some third culture created the tombs. So what? They’re halfway across the continent and the Swahili didn’t have any contact with them. So if the Swahili learned it from anyone, it would still have to be from the Oromo. (D) is descriptively inaccurate. The argument makes no such assumption because the argument doesn’t have to. The alternative hypothesis that (D) is concerned with was already precluded by the premises.

Correct Answer Choice (E) says that the argument assumes that the Oromo built their tombs earlier than the Swahili did. Yes, that’s definitely an assumption that the argument makes. In order for the Oromo to have influenced the Swahili, the Oromo had to have done it first. If the Swahili got there first, then perhaps it’s the Oromo who were influenced by the Swahili. (E) is descriptively accurate. More than that, (E) is why the argument is weak. There is no information about who got there first. Without that information, we cannot say whether the Oromo as influencer hypothesis or the Swahili as influencer hypothesis is more likely to be true. This is precisely where the argument is most vulnerable to criticism.

29 comments

This is a Flaw/Descriptive Weakening question.

The stimulus starts with other people’s (Smith’s) position (OPP). Smith proposed a new city ordinance prohibiting the use of a sleazy sales tactic. The author then insults Smith’s memory—okay. Then she says that four years ago, Smith owned a business that used the very same sleazy sales tactic. She concludes that Smith’s proposal does not merit consideration.

This is a terrible argument and one that we’ve seen many times before. It’s a source attack. If we want to oppose the ordinance, we should provide premises in support of that position. Attacking the source of the ordinance has no logical effect. It might be rhetorically effective, but that turns on how reasonable the audience is.

In general, source attacks fail. Just imagine how easily Smith can counter the author here. He just has to say something like, “Yeah, no shit. That’s how I know it’s a sleazy sales tactic and that’s why I’m proposing we ban it. I don’t have amnesia but you might have low-level brain damage.”

Correct Answer Choice (A) says the argument dismisses the ordinance because of its source rather than because of its content. This is exactly right.

Answer Choice (B) says the argument takes a single fact that is incompatible with a claim as enough to show that claim to be false. There are at least two issues with (B). First is simply that it’s descriptively inaccurate. The single fact (Smith’s business that used the sleazy sales tactic) is not incompatible with the claim (ban the sleazy sales tactic). That fact may actually be the reason for the claim. Second, even if (B) were descriptively accurate, what (B) describes isn’t inherently a flaw. Whether a single incompatible fact is enough to show a claim to be false depends on what the claim is. If the claim is that all cats are cute, you just have to show me one ugly-ass cat and that claim is dead.

Answer Choice (C) says the argument fails to make a needed distinction between deceptive and legitimate sales tactics. This is almost descriptively accurate. The argument did not make this distinction. But it also did not need to. The reason why the premise doesn’t support the conclusion has nothing to do with failing to define what a legitimate sales tactic looks like.

Answer Choice (D) says the argument draws a conclusion that simply restates a claim presented in support of that conclusion. This is a charge of circular reasoning, of begging the question. This is descriptively inaccurate. The premise is that Smith did something wrong. The conclusion is we should ignore Smith’s proposal to ban that wrong action in the future. These are two very different claims. The argument isn’t circular. Here’s a circular argument: Smith’s proposed city ordinance to prohibit the use of bait-and-switch sales tactics is ill-conceived. Clearly, it is utterly flawed.

Answer Choice (E) says the argument generalizes from a limited number of instances of a certain kind to all instances of that kind. This is an overgeneralization flaw. It’s descriptively inaccurate. Here’s an argument that commits that flaw: Smith’s appliance store uses sleazy sales tactics. Therefore, all of Smith’s businesses use sleazy sales tactics.

Comment on this

This is a Flaw/Descriptive Weakening question.

The stimulus starts with other people’s (Smith’s) position (OPP). Smith proposed a new city ordinance prohibiting the use of a sleazy sales tactic. The author then insults Smith’s memory—okay. Then she says that four years ago, Smith owned a business that used the very same sleazy sales tactic. She concludes that Smith’s proposal does not merit consideration.

This is a terrible argument and one that we’ve seen many times before. It’s a source attack. If we want to oppose the ordinance, we should provide premises in support of that position. Attacking the source of the ordinance has no logical effect. It might be rhetorically effective, but that turns on how reasonable the audience is.

In general, source attacks fail. Just imagine how easily Smith can counter the author here. He just has to say something like, “Yeah, no shit. That’s how I know it’s a sleazy sales tactic and that’s why I’m proposing we ban it. I don’t have amnesia but you might have low-level brain damage.”

Correct Answer Choice (A) says the argument dismisses the ordinance because of its source rather than because of its content. This is exactly right.

Answer Choice (B) says the argument takes a single fact that is incompatible with a claim as enough to show that claim to be false. There are at least two issues with (B). First is simply that it’s descriptively inaccurate. The single fact (Smith’s business that used the sleazy sales tactic) is not incompatible with the claim (ban the sleazy sales tactic). That fact may actually be the reason for the claim. Second, even if (B) were descriptively accurate, what (B) describes isn’t inherently a flaw. Whether a single incompatible fact is enough to show a claim to be false depends on what the claim is. If the claim is that all cats are cute, you just have to show me one ugly-ass cat and that claim is dead.

Answer Choice (C) says the argument fails to make a needed distinction between deceptive and legitimate sales tactics. This is almost descriptively accurate. The argument did not make this distinction. But it also did not need to. The reason why the premise doesn’t support the conclusion has nothing to do with failing to define what a legitimate sales tactic looks like.

Answer Choice (D) says the argument draws a conclusion that simply restates a claim presented in support of that conclusion. This is a charge of circular reasoning, of begging the question. This is descriptively inaccurate. The premise is that Smith did something wrong. The conclusion is we should ignore Smith’s proposal to ban that wrong action in the future. These are two very different claims. The argument isn’t circular. Here’s a circular argument: Smith’s proposed city ordinance to prohibit the use of bait-and-switch sales tactics is ill-conceived. Clearly, it is utterly flawed.

Answer Choice (E) says the argument generalizes from a limited number of instances of a certain kind to all instances of that kind. This is an overgeneralization flaw. It’s descriptively inaccurate. Here’s an argument that commits that flaw: Smith’s appliance store uses sleazy sales tactics. Therefore, all of Smith’s businesses use sleazy sales tactics.

Comment on this

This is a Flaw/Descriptive Weakening question.

The stimulus starts with distinguishing categories of celestial objects. Stars versus planets. Stars generate light. Planets do not generate light, they only reflect it. Next, the argument defines a domain: this galaxy. It says that under this domain (in this galaxy), there are celestial objects that are neither stars nor planets, but it doesn’t give them names. (Fortunately, we already know their names: moons, asteroids, black holes, etc.) The argument then concludes that these nameless objects (i.e., these celestial objects that are neither planets nor stars) generate light.

Wait, what? The premises don’t support the conclusion at all! The premises establish that planets don’t generate light. It also establishes that there are other non-star, non-planet, nameless objects. But it says nothing about whether those nameless objects generate light. Where did that even come from?

As it turns out, Correct Answer Choice (E) reveals that the argument made the oldest mistake in the book: sufficiency-necessity. But this was such an unforced and bizarre error that it very successfully obscured itself. I certainly didn’t see this coming because I never would have expected the argument to confuse “planets don’t generate light (p→/gl)” with “only planets don’t generate light (/gl→p).” Had the premises established that “only planets don’t generate light” and there are non-star and non-planet objects, then those nameless objects would generate light. But the argument in fact only established that “planets don’t generate light.” It failed to consider the possibility that planets are not the only celestial objects that don’t generate light. For example, moons and asteroids also don’t generate light.

Answer Choice (A) says the argument failed to consider the possibility that this galaxy contains no celestial objects that reflect light other than planets. This is such an irrelevant consideration that I guess the argument failed to consider it. But that’s not why the argument’s reasoning is flawed. The conclusion is claiming that the nameless objects generate light. (A) is concerned with whether these nameless objects reflect light. Who cares if they reflect light or not?

Answer Choice (B) says the argument failed to consider the possibility that celestial objects in this galaxy comprise only a minute percentage of all the celestial objects in the universe. Similar to (A), this is such an irrelevant consideration that I guess the argument failed to consider it. But that’s not why the argument’s reasoning is flawed. The argument already established its domain: this galaxy. The conclusion does not exceed the bounds of that domain.

Answer Choice (C) says the argument failed to consider the possibility that celestial objects in this galaxy are not the only celestial objects that generate light. Similar to (A) and (B), this is such an irrelevant consideration that I guess the argument failed to consider it. But that’s not why the argument’s reasoning is flawed. (B) claims that there may be celestial objects in other galaxies that generate light. Okay, but who cares? The argument already established its domain: this galaxy. The conclusion does not exceed the bounds of that domain.

Answer Choice (D) says the argument failed to consider the possibility that there are numerous features that distinguish stars from planets besides the ability to generate light. Similar to (A), (B), and (C), this is such an irrelevant consideration that I guess the argument failed to consider it. But that’s not why the argument’s reasoning is flawed. It doesn’t matter what other features distinguish planets from stars. Stars tend to be bigger. Stars tend to live longer. Great. Who cares?

12 comments

This is a Flaw/Descriptive Weakening question.

The stimulus starts with distinguishing categories of celestial objects. Stars versus planets. Stars generate light. Planets do not generate light, they only reflect it. Next, the argument defines a domain: this galaxy. It says that under this domain (in this galaxy), there are celestial objects that are neither stars nor planets, but it doesn’t give them names. (Fortunately, we already know their names: moons, asteroids, black holes, etc.) The argument then concludes that these nameless objects (i.e., these celestial objects that are neither planets nor stars) generate light.

Wait, what? The premises don’t support the conclusion at all! The premises establish that planets don’t generate light. It also establishes that there are other non-star, non-planet, nameless objects. But it says nothing about whether those nameless objects generate light. Where did that even come from?

As it turns out, Correct Answer Choice (E) reveals that the argument made the oldest mistake in the book: sufficiency-necessity. But this was such an unforced and bizarre error that it very successfully obscured itself. I certainly didn’t see this coming because I never would have expected the argument to confuse “planets don’t generate light (p→/gl)” with “only planets don’t generate light (/gl→p).” Had the premises established that “only planets don’t generate light” and there are non-star and non-planet objects, then those nameless objects would generate light. But the argument in fact only established that “planets don’t generate light.” It failed to consider the possibility that planets are not the only celestial objects that don’t generate light. For example, moons and asteroids also don’t generate light.

Answer Choice (A) says the argument failed to consider the possibility that this galaxy contains no celestial objects that reflect light other than planets. This is such an irrelevant consideration that I guess the argument failed to consider it. But that’s not why the argument’s reasoning is flawed. The conclusion is claiming that the nameless objects generate light. (A) is concerned with whether these nameless objects reflect light. Who cares if they reflect light or not?

Answer Choice (B) says the argument failed to consider the possibility that celestial objects in this galaxy comprise only a minute percentage of all the celestial objects in the universe. Similar to (A), this is such an irrelevant consideration that I guess the argument failed to consider it. But that’s not why the argument’s reasoning is flawed. The argument already established its domain: this galaxy. The conclusion does not exceed the bounds of that domain.

Answer Choice (C) says the argument failed to consider the possibility that celestial objects in this galaxy are not the only celestial objects that generate light. Similar to (A) and (B), this is such an irrelevant consideration that I guess the argument failed to consider it. But that’s not why the argument’s reasoning is flawed. (B) claims that there may be celestial objects in other galaxies that generate light. Okay, but who cares? The argument already established its domain: this galaxy. The conclusion does not exceed the bounds of that domain.

Answer Choice (D) says the argument failed to consider the possibility that there are numerous features that distinguish stars from planets besides the ability to generate light. Similar to (A), (B), and (C), this is such an irrelevant consideration that I guess the argument failed to consider it. But that’s not why the argument’s reasoning is flawed. It doesn’t matter what other features distinguish planets from stars. Stars tend to be bigger. Stars tend to live longer. Great. Who cares?

16 comments

This is a Flaw/Descriptive Weakening question.

This is a causal argument with phenomenon-premises and a hypothesis-conclusion. The first premise reveals that for physical therapy patients that received less than six weeks of treatment, around a third showed major improvement. This result was the same regardless of whether the treatment was by a generalist or specialist. The second premise reveals a similar phenomenon for longer treatment. This time, around half showed major improvement. Again, the result was the same regardless of whether the treatment was by a generalist or specialist.

So those are all the facts we have. That’s collectively the “phenomenon.” What causal conclusion can be drawn? Well, not much. Certainly not the conclusion actually drawn: the choice between a generalist and specialist makes no difference.

Let’s say you wanted to test this hypothesis. You think that the choice between a generalist and specialist makes no difference. How would you go about designing your (ideal) experiment? I put “ideal” in parentheses because it really doesn’t have to be ideal. It just has to be better than the data in the stimulus and that’s a low bar. So, you’d collect a ton of people prescribed less than six weeks of physical therapy. Then you’d randomly assign them to specialists and generalists. Then you wait out the six weeks and you measure to see what percentage in each group experienced major improvement. If it turns out that about a third experienced major improvement in either group, then that’s good evidence that the choice between generalist and specialist has no causal power. (And then you do it all over again for the long-term treatment.) But notice how different that is from what actually happened in the stimulus. The stimulus presented observational data, not experimental data. That means there were no controls. Specifically, there were no controls for self-selection. The assignment to generalist or specialist was not random. People chose whether to see a generalist or a specialist and presumably with good reason! What reason? Maybe because generalists and specialists are better suited to treat different kinds of injuries.

This is exactly what Correct Answer Choice (E) points out. This argument is vulnerable because it overlooked the possibility that generalists and specialists each excel at treating a different type of injury. (E) is subtle in exposing the flawed logic of the argument. I’m pretty blunt so let me shine a spotlight on this error with the following argument.

Records reveal that of patients who received heart surgery, about 75% regained full cardiovascular functions one month post operation regardless of whether they received a double bypass or a quadruple bypass surgery. Therefore the choice of a double or quadruple bypass will not affect one’s chances of regaining full cardiovascular function.

Is the flaw glaring now? Imagine telling the patient who’s scheduled for a quadruple bypass that actually, you know what, you don’t need four unclogged arteries, let’s just clear up two of them and you’ll be fine.

Answer Choice (D) is very attractive. It claims that the reasoning is vulnerable because the argument failed to indicate whether the number of patients surveyed who saw a generalist was equivalent to the number who saw a specialist. While (D) is descriptively accurate, the argument’s failure to indicate isn’t where the argument is weak. To see this, imagine if we supplied an additional premise that fixed this “problem” by indicating what (D) wants. So the same argument, but now an additional premise indicates that the numbers were equal. Voila, the conclusion follows! Just kidding. The argument is still garbage for all the reasons discussed above.

If (D) was attractive to you, perhaps you thought that experiments require equal group sizes? First, note that (D) isn’t talking about an experiment (because the stimulus isn’t an experiment). Second, it’s not true that equal sizes are a requirement for experiments. It’s nice to have (for statistical reasons) but it’s not necessary. I think you can intuitively understand this just by imagining an experiment where one group was slightly larger than the other, say 60/40. Your results will still be fine as long as you avoid the other experimental pitfalls (random assignment, blinding, etc.).

Answer Choice (A) is also attractive though for a different reason. (A) is attractive mainly because it’s gibberish but fancy-sounding gibberish. It claims that the argument is vulnerable because it assumes (without warrant) that if the effectiveness of different practitioners in bringing about any (which includes minor) improvement does not differ, then their effectiveness in bringing about major improvement cannot differ. What? No, the argument makes no such assumption. The argument does not assume there is no difference in how effective generalists and specialists are with respect to bringing about minor improvements.

Answer Choice (B) claims that the argument provides no information about the kinds of injuries that require short-term versus long-term treatment. Okay, this is descriptively accurate but nobody cares because this isn’t why the argument is weak. I think (B) could have been right had the argument been edited just a little. Like this: Records reveal that regardless of whether patients receive short-term (six weeks) or long-term treatment, about 50% experience major improvements within six weeks. Therefore, the choice between short- or long-term will not affect one’s chances of major improvement. This argument is weak because it assumed that the assignment was random whereas it almost certainly was not. It almost certainly was the case that there was self-selection determining who got short-term and who got long-term. And that’s because doctors diagnose and prescribe proportional treatment. One way to describe this weakness is to say that the argument should have provided information about the kinds of injuries that require short-term as opposed to long-term treatment. That information would have most likely revealed that it’s the more severe injuries that require long-term treatment.

Answer Choice (C) claims that the argument overlooks the possibility that patients are more strongly biased to report favorably on one of the two types of medical professionals than on the other. (C) thinks the weakness in the argument has to do with whether the “one third” and “one half” major improvement results are believable. This kind of objection, the “wait, but are you sure your data maps onto reality?” is more powerful in arguments that rely on survey results. It’s not clear this is such an argument. The premises say, “records reveal.” What kind of records? How was the data collected? Did we ask the patients if they showed major improvement? Or did we simply measure their physical abilities to determine major improvement? If the latter, then (C) completely misses the mark for it assumes the data came from subjective reports. If we patch this issue up, then (C) at best identifies a minor issue in the argument. While it’s true that the argument does assume that these records reflect reality, the argument also failed to account for self-selection. That second issue is the major one because if that were fixed, the argument would improve dramatically whereas if we fixed the “records reflect reality” issue, the argument would still be flawed.

17 comments

This is a Flaw/Descriptive Weakening question.

This is a causal argument with phenomenon-premises and a hypothesis-conclusion. The first premise reveals that for physical therapy patients that received less than six weeks of treatment, around a third showed major improvement. This result was the same regardless of whether the treatment was by a generalist or specialist. The second premise reveals a similar phenomenon for longer treatment. This time, around half showed major improvement. Again, the result was the same regardless of whether the treatment was by a generalist or specialist.

So those are all the facts we have. That’s collectively the “phenomenon.” What causal conclusion can be drawn? Well, not much. Certainly not the conclusion actually drawn: the choice between a generalist and specialist makes no difference.

Let’s say you wanted to test this hypothesis. You think that the choice between a generalist and specialist makes no difference. How would you go about designing your (ideal) experiment? I put “ideal” in parentheses because it really doesn’t have to be ideal. It just has to be better than the data in the stimulus and that’s a low bar. So, you’d collect a ton of people prescribed less than six weeks of physical therapy. Then you’d randomly assign them to specialists and generalists. Then you wait out the six weeks and you measure to see what percentage in each group experienced major improvement. If it turns out that about a third experienced major improvement in either group, then that’s good evidence that the choice between generalist and specialist has no causal power. (And then you do it all over again for the long-term treatment.) But notice how different that is from what actually happened in the stimulus. The stimulus presented observational data, not experimental data. That means there were no controls. Specifically, there were no controls for self-selection. The assignment to generalist or specialist was not random. People chose whether to see a generalist or a specialist and presumably with good reason! What reason? Maybe because generalists and specialists are better suited to treat different kinds of injuries.

This is exactly what Correct Answer Choice (E) points out. This argument is vulnerable because it overlooked the possibility that generalists and specialists each excel at treating a different type of injury. (E) is subtle in exposing the flawed logic of the argument. I’m pretty blunt so let me shine a spotlight on this error with the following argument.

Records reveal that of patients who received heart surgery, about 75% regained full cardiovascular functions one month post operation regardless of whether they received a double bypass or a quadruple bypass surgery. Therefore the choice of a double or quadruple bypass will not affect one’s chances of regaining full cardiovascular function.

Is the flaw glaring now? Imagine telling the patient who’s scheduled for a quadruple bypass that actually, you know what, you don’t need four unclogged arteries, let’s just clear up two of them and you’ll be fine.

Answer Choice (D) is very attractive. It claims that the reasoning is vulnerable because the argument failed to indicate whether the number of patients surveyed who saw a generalist was equivalent to the number who saw a specialist. While (D) is descriptively accurate, the argument’s failure to indicate isn’t where the argument is weak. To see this, imagine if we supplied an additional premise that fixed this “problem” by indicating what (D) wants. So the same argument, but now an additional premise indicates that the numbers were equal. Voila, the conclusion follows! Just kidding. The argument is still garbage for all the reasons discussed above.

If (D) was attractive to you, perhaps you thought that experiments require equal group sizes? First, note that (D) isn’t talking about an experiment (because the stimulus isn’t an experiment). Second, it’s not true that equal sizes are a requirement for experiments. It’s nice to have (for statistical reasons) but it’s not necessary. I think you can intuitively understand this just by imagining an experiment where one group was slightly larger than the other, say 60/40. Your results will still be fine as long as you avoid the other experimental pitfalls (random assignment, blinding, etc.).

Answer Choice (A) is also attractive though for a different reason. (A) is attractive mainly because it’s gibberish but fancy-sounding gibberish. It claims that the argument is vulnerable because it assumes (without warrant) that if the effectiveness of different practitioners in bringing about any (which includes minor) improvement does not differ, then their effectiveness in bringing about major improvement cannot differ. What? No, the argument makes no such assumption. The argument does not assume there is no difference in how effective generalists and specialists are with respect to bringing about minor improvements.

Answer Choice (B) claims that the argument provides no information about the kinds of injuries that require short-term versus long-term treatment. Okay, this is descriptively accurate but nobody cares because this isn’t why the argument is weak. I think (B) could have been right had the argument been edited just a little. Like this: Records reveal that regardless of whether patients receive short-term (six weeks) or long-term treatment, about 50% experience major improvements within six weeks. Therefore, the choice between short- or long-term will not affect one’s chances of major improvement. This argument is weak because it assumed that the assignment was random whereas it almost certainly was not. It almost certainly was the case that there was self-selection determining who got short-term and who got long-term. And that’s because doctors diagnose and prescribe proportional treatment. One way to describe this weakness is to say that the argument should have provided information about the kinds of injuries that require short-term as opposed to long-term treatment. That information would have most likely revealed that it’s the more severe injuries that require long-term treatment.

Answer Choice (C) claims that the argument overlooks the possibility that patients are more strongly biased to report favorably on one of the two types of medical professionals than on the other. (C) thinks the weakness in the argument has to do with whether the “one third” and “one half” major improvement results are believable. This kind of objection, the “wait, but are you sure your data maps onto reality?” is more powerful in arguments that rely on survey results. It’s not clear this is such an argument. The premises say, “records reveal.” What kind of records? How was the data collected? Did we ask the patients if they showed major improvement? Or did we simply measure their physical abilities to determine major improvement? If the latter, then (C) completely misses the mark for it assumes the data came from subjective reports. If we patch this issue up, then (C) at best identifies a minor issue in the argument. While it’s true that the argument does assume that these records reflect reality, the argument also failed to account for self-selection. That second issue is the major one because if that were fixed, the argument would improve dramatically whereas if we fixed the “records reflect reality” issue, the argument would still be flawed.

29 comments

This is a Parallel Flawed question.

The argument opens with premises that Devan has never been kind nor offered help nor companionship to me. These omissions are taken to amount to a failure to meet the basic requirements of friendship. Okay, so we can conclude that Devan is not the author’s friend.

But the author takes it a step further to conclude that Devan is his enemy.

What kind of flaw is this? False dichotomy. The author assumes that one can only be a friend or an enemy and not both. But the true dichotomy is friend or not friend. And not friend isn’t equivalent to enemy. Not friend is a super-set that contains enemy but it also contains acquaintances, colleagues, strangers, etc.

Answer Choice (A) begins by laying out necessary conditions for being an officer of this club. There are three disjunctive necessary conditions. One must either be a member of two years standing, or a committee member, or have special qualifications. Evelyn fails two of the three conditions. She has been a member for only one year and she is not a committee member. Okay, but does she also fail the third condition? Does she have special qualifications? The argument is silent. It assumes she doesn’t and on that assumption draws the conclusion that Evelyn cannot be an officer. This is poor reasoning but it’s not the same poor reasoning in the stimulus. There’s no false dichotomy.

Answer Choice (B) begins by laying out necessary conditions for a plant to thrive. There are two conjunctive necessary conditions. The plant must be located in a sunny spot and be watered regularly. The argument continues by failing one necessary condition. This spot isn’t sunny. Okay, that’s enough to fail the entire conjunctive necessary condition. We can validly draw the conclusion that this plant cannot be thriving. (B) attempts to fail the other necessary condition but does a bad job of it. The author didn’t regularly water this plant regularly. But that doesn’t mean the plant wasn’t watered regularly. Whose plant is it? Is it true that if the author didn’t water it, then no one watered it? The argument merely assumes so. But thankfully, we don’t care, since the necessary condition has been failed already.

Okay, so at this point, (B) is looking decent. The proper conclusion should be /thriving just like how the proper conclusion in the stimulus should be /friend. A false dichotomy for /thriving is “dead” or “dying.” That’s a false dichotomy because the true dichotomy for /thriving is a super-set that contains “dead” or “dying” or “just limping along” or “doing pretty good,” etc. There’s a whole spectrum of possibilities.

But the actual conclusion is “it explains why this plant is not as healthy as it should be.” That’s not a well-supported conclusion but for a different reason. This conclusion requires the assumption that the plant being “as healthy as it should be” means that it should be thriving. But thriving is a pretty high standard. (B) doesn’t give us any reason to believe that should be the standard.

Correct Answer Choice (C) opens with the premise that this book has been widely reviewed and hasn’t received even one hostile review. From that premise, (C) concludes that all the critics have loved this book. This is the false dichotomy flaw. The author assumes that one can only be hostile to or love the book and not both. But the true dichotomy is hostile to or not hostile. And not hostile isn’t equivalent to love. Not hostile is a super-set that contains love but it also contains indifference, like (not love), and other gradations of feelings.

Answer Choice (D) begins with a conditional that a decision in favor of developing the northern border of the town logically implies that it would be equally acceptable to develop the southern, eastern, or western borders. (D) concludes that it’s possible that at least one of the S, E, or W borders will also be developed. This is a strange argument. The premise has nothing to do with the conclusion. Just because it would be acceptable to develop doesn’t mean that development will take place. Moreover, we don’t even know if a decision in favor of developing the northern border has been reached.

Answer Choice (E) begins with a conditional that if everyone were an author, poet, or academic, then society would come to a halt. (E) then fails the sufficient condition. Few people are poets, authors, or academics. (E) then concludes that society will not come to a halt. This is sufficiency-necessity confusion. It’s the oldest flaw in the book but it’s not the flaw of false dichotomy.

7 comments