The question stem says the reasoning in the argument is most vulnerable to criticism on the grounds that the argument blank.

So that makes this a flaw question.

Let's go ahead and break down this argument and think about why the premises don't actually prove the conclusion.

We're told that some anthropologists argue that the human species could not have survived prehistoric times

So the first sentence is telling us what some anthropologists are arguing.

This is not the author. This is other people.

What those other people are saying is that if humans had not evolved the ability to cope in diverse natural environments,

and so I'll think of that as if they didn't have the ability to cope, then they would not have survived.

Now another way to express that statement, that idea, is if they did survive, that required the ability to cope in diverse natural environments.

This is just the contrapositive of the initial framing of that relationship.

Now the reason I put this diagram down is not because I think that in order to solve this question, you need to diagram this.

This is just for the purpose of explanation. I'm trying to show you the meaning of the statement.

And ultimately then, when you read that first sentence, I want you to have the takeaway that what this means is survival of the human species required the ability to cope in diverse environments.

This is what the anthropologist said.

Now let's see how the author responds to that claim.

However, there is considerable evidence that the Australopithecus afarensis, which is a prehistoric species related to early humans,

also thrived in a diverse array of environments, but it became extinct.

So now here the author is pointing out that there's this other species that is very similar to early humans or related to early humans,

and that other species had the ability to survive in diverse environments.

So that means they had the ability to cope in diverse environments.

So this other species had the ability to cope, but apparently this species went extinct.

So I'll think of that as and. Here's another fact about that species. It did not survive.

And just to make things visually clearer here, I'll note that the anthropologist claim this was about humans,

and then the author's claim here about how something had the ability to cope in diverse environments but still died, that one is about another species.

And now based on the fact that this other species had the ability to cope but still ended up dying, the author reaches this conclusion.

Hence, the anthropologist's claim is false. That's the author's conclusion being supported by the previous line, which is a premise.

Now we know that there's something flawed about this argument.

So can you think about why the author's premise doesn't actually prove that the anthropologist's claim is false?

The author thinks that this fact here proves the anthropologist's claim false,

but we know that there's some reason why that's not actually true.

There must be some reason why these facts do not contradict the anthropologist's claim.

And this problem essentially comes down to our understanding of what it means to contradict a conditional claim.

You see, the anthropologist told us that coping in diverse natural environments was required or necessary to survive.

Can we think about what it would actually take to contradict the anthropologist's claim?

What would be the information we would want to show that the anthropologist's are wrong?

Well, what we would want is an example of survival, but without the ability to cope in diverse natural environments.

If we could show that actually, here's a human type of species that survived,

but did not have the ability to cope in diverse natural environments,

that would prove that you don't need the ability to cope in diverse natural environments to survive.

You can just be specialized in one environment and still survive.

So what I have in green here, this is what would contradict and show that the anthropologist's claim is false.

And if you're confused by that, think about the claim, all apples are red.

So if apple, then red.

If you wanted to show that that claim was false, what would you want to do?

You'd want to point out an apple that was green.

An apple that was not red.

So to prove the statement that all apples are red is false,

I want an example of an apple, but that apple has the quality of not being red.

This is a contradiction of that.

But now let's compare what's in green, which is what would actually prove that the anthropologist's are false.

Let's compare that to what the author said.

The author is giving us an example of a human kind of species that had the ability to cope, but did not survive.

Is that relevant at all to proving the anthropologist's claim false?

And if you're at all in doubt about the answer to that question,

let me put up the all apples are red statement again.

All apples are red.

Could you contradict the claim that all apples are red by pointing to a red fruit that is not an apple?

Would the existence of red strawberries disprove the idea that all apples are red?

Of course not.

Saying that all apples are red is not the same thing as saying that all red fruits are apples.

So if you're trying to contradict the claim that every apple is red,

it's entirely irrelevant to point out that there are strawberries, that there are red fruits that are not apples.

So now the question is, why would someone think about pointing out that there are red fruits that are not apples?

Why would someone think about that as if it disproved the claim that all apples are red?

Well, the answer is because someone who brings up the fact that there are red fruits that are not apples,

someone who brings that up is misinterpreting the first claim.

They are interpreting the first claim not as all apples are red,

but they are interpreting it as every red fruit is an apple.

You see, if the initial claim was every red fruit was an apple,

then you could legitimately contradict that by showing, actually no, there are red fruits that are not apples.

But the problem is, the initial statement was not that every red fruit is an apple.

That's just a misinterpretation of the initial statement.

The initial statement actually was that all apples are red.

So now it's applied that structure to what's happening here.

Why does the author bring up the idea that here's a human kind of species that had the ability to cope but could not survive?

What makes the author think that that proves the anthropologist's claim false?

Well, it's because the author is misinterpreting what the anthropologist said.

The author is thinking that the anthropologist said that having the ability to cope in diverse environments is sufficient for survival.

In other words, that if the human species had the ability to cope, then that guarantees it would survive.

This right here, I'm going to put in like a thought bubble, because this is the author's misinterpretation.

What the anthropologist actually said was that the coping ability was necessary for survival,

meaning it was required in order to survive,

but the anthropologist were not saying that coping was sufficient for survival, that it would guarantee survival.

In the author's mind, however, the author is confusing the necessary condition with a sufficient condition,

or you could also phrase it as confusing a sufficient condition with a necessary condition.

The author has those concepts flipped and thinks the anthropologist said coping guaranteed survival.

That is why the author thinks, oh, you know what? You're wrong.

Here's something that coped but didn't survive.

And that is the flaw in the argument.

The author confused what the anthropologist said,

and that made the author bring up something that is actually irrelevant to what the anthropologist said.

What the author brought up does not prove that the anthropologists are wrong.

It proves that a twisted version of what the anthropologist said is wrong,

but it's not what the anthropologist said.

And by the way, here I just made things a little bit clearer.

I put the author's misinterpretation of the anthropologist's statement in a different color

just to make it consistent with what the author was saying.

And then for this green here, I just added this phrase negation

just to convey the idea that what's in green is like the true way to contradict the anthropologist's claim.

But that's different from what the author actually presented.

So let's take a look at these answers.

Answer choice A says that the argument confuses a condition's being required

with the conditions being sufficient for such a result to occur in a similar case.

And this is exactly right.

The author confuses a condition's being required for a given result to occur in one case.

That is a reference to the anthropologist's claim.

The anthropologist said that coping ability in diverse environments

was required in order for survival in the case of humans.

The anthropologist's claim concerned the human species.

But the author confused that required condition

as if it were a condition that is sufficient for such a result to occur.

Such a result is a reference to survival.

The author thought that coping was sufficient for survival.

And A says in a similar case because the author's facts here

technically didn't relate to human species but to the Australopithecus

which was related to early species.

So that is a similar case to humans.

A captures this confusion perfectly.

What the anthropologist said was that for humans coping ability was necessary for survival

but in the author's mind that meant that this Australopithecus

if it had the ability to cope would have been able to survive.

And because the author thought that the anthropologist were saying the Australopithecus

if it had coping ability would have been able to survive

that's why the author thinks pointing out that it did have the coping ability but did not survive

contradicts the anthropologist's claim.

But it doesn't.

It contradicts the twisted version of the anthropologist's claim.

It does not contradict what the anthropologist actually said.

That is why the argument is flawed.

So that's why answer choice A is correct.

Let's understand why the other answers are wrong.

that if one species had a characteristic that happened to enable it to survive certain conditions

at least one related extinct species must have had the same characteristic.

Now this is not what's going on because what B is accusing the author of doing

is by starting with as a premise the idea that one species had a characteristic

that enabled it to survive certain conditions

and then using that to reach a conclusion

that there must have been a related extinct species that must have had the same characteristic.

Now I know that a lot of people seem to be tempted by B because they think

oh well didn't the author bring up like this related extinct species

that must have had the same characteristic so it had like the coping ability.

But I think if you're seriously tempted by B you're not really internalizing the idea

that there is a directionality here.

In the argument the author used as a premise the existence of this other species

that had the ability to cope.

And from that fact the author tried to say that the anthropologists were false

or were wrong. That was the author's conclusion.

But the author was not trying to prove hey let me convince you

that there's this other species that had the ability to cope.

That's not the author's conclusion.

They're not trying to prove to you that there's this other species that's trying to cope

or has the ability to cope.

But that's what B is saying.

That the author is assuming that if one species had something that enabled it to survive

and you're probably thinking humans if you like that answer choice.

B is saying if the humans had the ability to cope

then there must have been at least this other extinct species that had the ability to cope.

That's not the author's assumption because the author isn't trying to go from

the existence of humans and ability to cope

to prove the existence of this other species and ability to cope.

That's one central reason why answer choice B is wrong.

It is simply a fact that this other species existed and had the ability to cope

and there's no assumption underlying the existence of that species.

The author's not assuming oh this other species must have existed because humans existed.

That's not what's happening but that's what B is saying.

Now another independent reason that B is wrong

is that actually there is nothing in this argument that presents

one species that had a characteristic that happened to enable it to survive.

A characteristic that enabled survival

is a characteristic that was sufficient for survival.

But the author's premise here is pointing out that

there was a species that had the ability to cope but did not survive.

So the author's premise isn't showing here's a species with a characteristic

that enabled survival. The species died.

So how could the characteristic have enabled survival here?

So that's another reason to get rid of answer choice B.

There just wasn't any species that had a characteristic that enabled it to survive.

And by the way if you're thinking that might refer to humans it doesn't

What anthropologists said was that coping ability was necessary for survival.

That doesn't mean coping ability enabled humans to survive.

So there are multiple reasons then B is wrong.

from the fact that one species with a certain characteristic survived certain conditions

that all related species with the same characteristic

must have survived exactly the same conditions.

Well no this is not what's happening.

And you can get rid of it actually just from the first clause.

The author is reaching a conclusion from a particular fact.

So the fact that the author is reaching a conclusion from

should match up with the author's premise.

Does the author's premise present the fact that one species

with a certain characteristic survived certain conditions?

Well no the author's premise shows a species that did not survive.

The author is reasoning from this fact to then say

the anthropologists are wrong. But the author is not reaching a conclusion

from the fact that there was a species that survived.

It's about a species that died. So C is already wrong.

On top of that C is pretending like the author's conclusion

is that all related species with the same characteristic

must have survived exactly the same conditions.

That's not the author's conclusion or rather assumption

because there's nothing about the author's argument that is trying to convince us

oh you know this other species must have lived in the exact same areas

the exact same environments. The author actually doesn't say anything about

whether the Australopithecus lived in the exact same environment as humans.

What the author points out is they had the same ability

to cope in diverse environments, a bunch of different environments

but that's not trying to say that they survived the exact same conditions.

They might have had very different conditions. It's just that they both had the ability

to survive in very different areas. So there's a lot of things

that's wrong with answer choice C. Let's take a look at D now

that Australopithecus afarensis had one or more characteristics

that lessened its chances of surviving prehistoric times.

He is trying to make the point, well hey author, what if

what actually happened was that this Australopithecus, this other species

it had characteristics that lessened its chances of survival

but that possibility would actually just go along

with the author's argument. Remember, in the author's mind

the anthropologist said that if the

Australopithecus or other kinds of human species

if they had the ability to cope, then that guarantees survival.

That's the author's misinterpretation of the anthropologist's claim.

So the author then thinks, oh you know what, I have a counter example.

Here's an Australopithecus that had the ability to cope

but did not survive. So therefore, anthropologist,

you're wrong. If you come along with what D says and you

says, oh but author have you considered that the

Australopithecus might have been like really slow

and so that's why it like had a hard time surviving,

the author would say, yeah I know, I'm pointing out that they died.

And I think the fact that they died shows that coping ability

is not sufficient for survival. If you come along and explain to me,

oh here are the features that helped lead it to die.

Here's the things that made it extinct. That doesn't undermine

the author's conception of what's going on. Nor does that point out

how the author's conception of what's going on is wrong.

That's just telling me here are specific reasons why it might not have

survived and then the author would say, well yeah, I'm trying to show

that they didn't survive and that's what makes me think the anthropologist

are wrong. So because D is just going along with the author's

interpretation, D is not pointing out a flaw. Now I think

D might be tempting because you might be thinking, oh but

doesn't pointing out that the Australopithecus

might have had characteristics that would cause it to die,

isn't that showing why it's like inappropriate to draw

this conclusion that if it coped, then it would have been

able to survive? Because like there's stuff that could have made it die.

But if that's your line of reasoning, the problem is, this right here, this is not

the author's conclusion. I agree with you that it would be wrong to

conclude this and D is like trying to point out, oh here are

some reasons why coping ability is not sufficient

for survival. So yes, it would be wrong to conclude that

coping ability is sufficient for survival. But that's not what the author

concluded. This is simply the wrong way that the

author was interpreting the anthropologist's statement.

The anthropologist said one thing and then in the author's mind,

he switched it around and thought that they said something else. And then

the author brought up an example designed to contradict

what the author thought the anthropologist said. And the possibility

described in D, if you go along with the author's

misconception here, would just be completely consistent

with what the author's theory is. The author already

recognizes that the Australopithecus died.

They are trying to use the fact that it died to prove the anthropologist

wrong. So pointing out a possibility that would help show

that it could have died, here's why it could have died, doesn't go against

the author's theory. They are fully open to the possibility that D says.

And finally, E says that the argument fails to consider

a result to occur in one case, it was not necessary

to cause the result to occur in a similar case.

Okay, first of all, is there a condition that caused a result

to occur in one case? The answer is no.

When the anthropologist said that coping ability in diverse environments

was necessary to survival, that is not the same thing as

saying that coping ability caused humans to survive.

I know it kind of sounds like it is, but if you're being strict about

the actual meaning of the statement, it is not a causal claim.

I mean, I'm okay with describing survival as

like a result, so you could say that coping ability was

necessary for the result of survival, but that doesn't

mean that coping ability caused survival.

It is just a necessary condition for survival. And if you look at what the author

said, the author also didn't say that one thing caused another thing.

They just pointed out that here's a thing that coped, here's a

human species or related human species that coped and

didn't survive, but the author isn't saying that coping caused

lack of survival. It caused it to die. So there's just nothing

that matches up with a condition caused a result to occur

in one case. That's enough to get rid of answer choice E.

Now in case you're curious for the kind of argument that would be committing

the flaw that he describes, take a look at this. The premise is

smoking caused Bob's cancer, so here's a condition

that caused a certain result to occur in one case, but then the author

reaches a conclusion, so smoking must have caused Jane's cancer.

That's flawed because people can get cancer for many different

reasons, but the author thinks that because smoking caused Bob's

cancer, that it was necessary to cause Jane's

cancer, that it must have caused Jane's cancer. This is the flaw

that E is describing, where the author essentially overlooks

the possibility of multiple causes for the same result.

That's not what's happening here. As I said earlier, this argument

is not actually a causal argument. The author isn't trying to say that

one thing caused another, and I hope that this example can show you

how different the author's actual argument here is

from the kind of argument that is doing E.