The typological theory of species classification, which has few

Question

The typological theory of species classification, which has few adherents today, distinguishes species solely on the basis of observable physical characteristics, such as plumage of color, adult size, or dental structure. However, there are many so called "sibling species", which are indistinguishable on the basis of their appearance but can not interbreed and thus, according to the mainstream biological theory of species classification, are separate species. Since the typological theory does not count sibling species as separate species, it is unacceptable.

The reasoning in the argument is most vulnerable to criticism on the grounds that:

(A) The argument does not evaluate all aspects of the typological theory

(B) The argument confuses a necessary condition for species distinction with a sufficient condition for species distinction

(C) The argument, in its attempt to refute one theory of species classification, presupposes the truth of an opposing theory

(D) The argument takes single fact that is incompatible with a theory as enough to show that theory to be false

(E) The argument does not explain why sibling species can not interbreed

kanakdaga · Accepted Answer

The  typological theory  of species classification, which has few adherents today, distinguishes species  solely on the basis of observable physical characteristics , such as plumage of color, adult size, or dental structure. However, there are many so called  "sibling species", which are indistinguishable on the basis of their appearance  but  can not interbreed  and thus,  according to the mainstream biological theory of species classification, are separate species . 
 CONCLUSION : Since the typological theory does not count sibling species as separate species, it is unacceptable.

The reasoning in the argument is most  vulnerable to criticism  on the grounds that:

(A) The argument does not evaluate all aspects of the typological theory. 
 True but it doesn't evaluate all aspects of the other theory also. So, INCORRECT.

(B) The argument confuses a necessary condition for species distinction with a sufficient condition for species distinction. 
 We cannot say for sure which one is the necessary condition- physical traits or interbreeding. Ambiguous , INCORRECT

(C) The argument, in its attempt to refute one theory of species classification, presupposes the truth of an opposing theory.
 CORRECT. The author says that because X is missing in a theory, which is based on presence of Y, it (theory) should be refuted. Next the author says that a theory which is based on X is acceptable even though it lacks Y.

(D) The argument takes single fact that is incompatible with a theory as enough to show that theory to be false.
 True but insufficient. Not the best choice. INCORRECT

(E) The argument does not explain why sibling species can not interbreed.  Irrelavant. INCORRECT

ruchik · Answer

Can someone post the OA explanation for this question. Want to know why D is incorrect.
According to be D seems to be a better choice than C.

twister68 · Answer

Even I feel D is right. The second theory is not an opposite or opposing theory. Both of these theories have different basis. D is right because author has taken one fact of other theory, which is not compatible with first theory, as a basis to declare that its first theory is wrong.

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kanakdaga · Answer

Hi. 
D assumes that the fact -- though incompatible with the typological theory -- is a fact that cannot be overlooked. Such a reasoning is not implied anywhere. The biological theory encompasses this particular fact but it has also not been explicitly mentioned that biological theory is accepted. 
Thus rejecting the typological theory merely on this basis does not seem to be a correct answer.

In C : (C) The argument, in its  attempt to refute one theory  of species classification,  presupposes the truth of an opposing theory 
Everything that is obscure in option D falls in place in option C.  Thus C is the  best  answer choice.

Please KUDOS if this helps! :D

rish2708 · Answer

Hi,
I have a small doubt. The option C says that both theories are opposing each other, but both biological theory and typological theory are not kept as theories opposing each other right? How are we saying that both are opposing theories?

Though I agree with your explanation that D can be ruled out since the fact is not proven to be valid.

Posted from my mobile device

kanakdaga · Answer

Thats a good point. 
But these are opposing as long as the primary basis of the theories are considered. 
Typological theory focuses on the physical attributes while biological theory is focusing on the internal and inherent aspects. 
However, we eliminated D because we can't assume that for a theory to be acceptable it has to be based on the facts that are assumed by the biological theory.

I hope I was able to answer.
Please KUDOS if this helps! :D

Megha1119 · Answer

Why can't the answer choice be B? Are we not discarding the typological theory on the grounds that it does not consider interbreeding as one of the necessary conditions?

Posted from my mobile device

nightblade354 · Answer

twister68 ,

The OA is indeed (C). If you are looking for an in depth breakdown of the question's answers, I'd be happy to provide one.

Megha1119 ,

There is are no conditional statements made, so (B) cannot be our answer.

kanakdaga · Answer

Is interbreeding a sufficient condition?
No. It has neither implied anywhere nor stated.

ruchik · Answer

nightblade354  thanks for help. Can you please provide in depth analysis of the question.

ruchik · Answer

nightblade354 : can you please provide in depth breakdown of the answers.

nightblade354 · Answer

The typological theory of species classification, which has few adherents today, distinguishes species solely on the basis of observable physical characteristics, such as plumage of color, adult size, or dental structure. However, there are many so called "sibling species", which are indistinguishable on the basis of their appearance but can not interbreed and thus, according to the mainstream biological theory of species classification, are separate species. Since the typological theory does not count sibling species as separate species, it is unacceptable.

The reasoning in the argument is most vulnerable to criticism on the grounds that:

(A) The argument does not evaluate all aspects of the typological theory --  OK......it would be almost impossible to break down ALL aspects of a theory. Further, we are comparing two distinct theories, so evaluating one completely is a bit out of scope.

(B) The argument confuses a necessary condition for species distinction with a sufficient condition for species distinction --  There are no conditional indicators present. For example, if it said "if they can mate, then they are part of X theory", this would be a sufficient and necessary conditional statement. But, as it is not stated this is not our answer.

(C) The argument, in its attempt to refute one theory of species classification, presupposes the truth of an opposing theory --  This says the mainstream science is being used to show that another theory does not work. This is, indeed, our flaw and our answer!

(D) The argument takes single fact that is incompatible with a theory as enough to show that theory to be false --  The closest thing to being a right answer. But this is sound logic. If something is known to be an indicator and it does not work, then we know that it probably doesn't work. You are using a single counter example to disprove a claim. There is nothing wrong with this in terms of a flaw. The statement goes with the argument, not against it. 
 
(E) The argument does not explain why sibling species can not interbreed --  Who cares why they cannot? The argument does not try to prove otherwise.

ramalcha · Answer

Please could this be evaluated as I cannot understand the reasoning

Skywalker18 · Answer

The typological theory of species classification, which has few adherents today, distinguishes species solely on the basis of observable physical characteristics, such as plumage of color, adult size, or dental structure. However, there are many so called "sibling species", which are indistinguishable on the basis of their appearance but can not interbreed and thus, according to the mainstream biological theory of species classification, are separate species. Since the typological theory does not count sibling species as separate species, it is unacceptable.

Conclusion- the typological theory is unacceptable because it categorizes "sibling species" as the same species but mainstream theory says they are separate.

The reasoning in the argument is most vulnerable to criticism on the grounds that:

(A) The argument does not evaluate all aspects of the typological theory - incorrect; is wrong since you don't have to evaluate every aspect of a theory to conclude it's unacceptable. One bad part can ruin it!

(B) The argument confuses a necessary condition for species distinction with a sufficient condition for species distinction- no conditional statements here

(C) The argument, in its attempt to refute one theory of species classification, presupposes the truth of an opposing theory - Correct; the argument assumes that mainstream theory is correct.

(D) The argument takes single fact that is incompatible with a theory as enough to show that theory to be false - incorrect; The issue is that citing a single counterexample to an absolute rule is an acceptable way to argue -- it's not a flaw!

(E) The argument does not explain why sibling species can not interbreed- irrelevant

Answer C

VIGHNESHKAMATH · Answer

I really doubt the logic of the OA. Argument nowhere states that the mainstream theory is acceptable. Why are we assuming this? It only states that typological theory is unacceptable because it is not able to classify sibling species, which mainstream theory is able to achieve. But it doesn't exclusively state that ''therefore mainstream is theory is acceptable.'' So, we cannot assume that. It is simply comparing two theories on a single parameter of sibling species and stating that ''yes mainstream can classify the sibling species'', so it is not presupposing the truth of the opposing theory. Presupposing would mean , ''therefore mainstream theory is acceptable''

On the other hand, I think closest answer should be Option A. How can the argument state a typological theory to be unacceptable, just by stating one facet of sibling species. Perhaps, typological theory has other considerable factors which could make it acceptable in its own right. I know A is bit extreme in stating ''all factors'' but still relatively it looks better to me than Option C.

Any thoughts on this?

Regards
Vighnesh

gurugmat · Answer

Hi Vignesh,
Here we need to identify the flaw in author's reasoning. Author concludes that just because the typological theory doesn't correspond to the mainstream theory, it must be unacceptable. Answer C says that author has assumed that mainstream theory is correct in order to prove that typological theory is false. what if mainstream theory is wrong? This is the flaw answer choice C is highlighting.
Hope it helps

kumarvibhuti630 · Answer

Conclusion:
Since the typological theory does not count sibling species as separate species, it is unacceptable.

(A) irelevant

(B) The argument does't assume interbreeding as sufficient conditon.

(C) Correct: Able to identify after eliminating all other options, it is exactly what argument is doing, as the argument is rejecting one theory basically by assuming that mainstream theory is a correct theory.

(D) The main reason to eliminate the answer is single usage of fact, as we are dealing with theories and a fact must be true. It is saying that above information is correct and we are rejecting on 1 fact basis.

(E) irrelevant

The typological theory of species classification, which has few

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The typological theory of species classification, which has few

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