#18 - The consensus among astronomers, based upon

[Administrator]

Please post below with any questions!

[cjj]

I eliminated all but A and D here, but ended up choosing D. D won out b/c it seemed more relevant to the stimulus, as they both refer to the consensus view. Why is A the better answer?

[couldbetanner]

I think what makes A a better answer than D is that the stimulus doesn't really give us any indication that these observations are being made about the entire structure, rather they claim that they are made based on surface observations.

Also, I think since the stimulus says these observed properties are consistent with some pulsars being filled with quarks, it isn't really a new finding and it doesn't challenge the consensus because it is not saying all pulsars are this way, only some.

at least that is what was going through my head when I picked A.

[Jonathan Evans]

Thank you both for the good discussion and for sharing your reasoning about this problem!

Since we're dealing with a Method of Reasoning question, there must be some kind of logical structure to the stimulus. Let's start by finding the main conclusion.

• The consensus view is that pulsars are composed entirely of neutrons. However, here's some evidence that points in another direction.

Thus, the main conclusion is "there is another possible explanation for the structure of neutrons consistent with observations."

After we find the main conclusion, on a Method of Reasoning problem we must describe how the rest of the argument leads up to this conclusion.

• The author concludes there is another possible explanation for the structure of neutrons consistent with observations.
• She bases this conclusion on her supposition that just the top crust could be composed of neutrons.
• She claims this is possible because the neutrons could be on top of negatively charged particles.
• The negatively charged particles would be there because the underlying quarks would have a positive charge.

Notice what we've done there; we've stepped logically backwards from the conclusion through the support the author gives in the premises. Also notice how the premises lead to each other before we finally arrive at the main conclusion. You could picture this chain of support as follows:

• Underlying quarks have positive charge Negative charged particles on top of them supporting neutron crust Another possible composition for neutron stars

Let's focus now on the specific part of the argument about which the question asks, the statement about underlying quarks having a positive charge.

• Underlying quarks have positive charge Negative charged particles on top of them supporting neutron crust Another possible composition for neutron stars

What role does this statement play? Our prephrase could be:

• It provides support for the idea that negatively charged particles could be on top supporting a neutron crust.

This intermediate statement can be called a "subordinate conclusion." It is a statement, backed up by evidence, which in turn backs up another conclusion. In this case, the subordinate conclusion is about the neutron crust. This subordinate conclusion then backs up the main conclusion about another possible composition for neutron stars.

Notice how our prephrase is an excellent match for answer choice A. However, answer choice D goes a little off track and takes it too far. The specific role of the statement about quarks leads directly to the neutron crust statement but does not go all the way to the main conclusion.

Further, as CouldBeTanner correctly notes, it is not a new "finding."

I hope this helps!

[cjj]

Thank you both very much! That was super helpful and all makes sense now

[theamazingrace]

Thank you both for the good discussion and for sharing your reasoning about this problem!

Since we're dealing with a Method of Reasoning question, there must be some kind of logical structure to the stimulus. Let's start by finding the main conclusion.

• The consensus view is that pulsars are composed entirely of neutrons. However, here's some evidence that points in another direction.

Thus, the main conclusion is "there is another possible explanation for the structure of neutrons consistent with observations."

After we find the main conclusion, on a Method of Reasoning problem we must describe how the rest of the argument leads up to this conclusion.

• The author concludes there is another possible explanation for the structure of neutrons consistent with observations.
• She bases this conclusion on her supposition that just the top crust could be composed of neutrons.
• She claims this is possible because the neutrons could be on top of negatively charged particles.
• The negatively charged particles would be there because the underlying quarks would have a positive charge.

Notice what we've done there; we've stepped logically backwards from the conclusion through the support the author gives in the premises. Also notice how the premises lead to each other before we finally arrive at the main conclusion. You could picture this chain of support as follows:

• Underlying quarks have positive charge Negative charged particles on top of them supporting neutron crust Another possible composition for neutron stars

Let's focus now on the specific part of the argument about which the question asks, the statement about underlying quarks having a positive charge.

• Underlying quarks have positive charge Negative charged particles on top of them supporting neutron crust Another possible composition for neutron stars

What role does this statement play? Our prephrase could be:

• It provides support for the idea that negatively charged particles could be on top supporting a neutron crust.

This intermediate statement can be called a "subordinate conclusion." It is a statement, backed up by evidence, which in turn backs up another conclusion. In this case, the subordinate conclusion is about the neutron crust. This subordinate conclusion then backs up the main conclusion about another possible composition for neutron stars.

Notice how our prephrase is an excellent match for answer choice A. However, answer choice D goes a little off track and takes it too far. The specific role of the statement about quarks leads directly to the neutron crust statement but does not go all the way to the main conclusion.

Further, as CouldBeTanner correctly notes, it is not a new "finding."

I hope this helps!

How is " the core of a quark-filled pulsar would have an overall positive charge" an intermediate statement /subordinate conclusion that is, backed up by evidence, which in turn backs up another conclusion? When I saw "because of the core..." I thought to myself that what followed would be some sort of premise. Also, would it be fair to say that the main conclusion presents a new finding?

Thanks!

[Robert Carroll]

Grace,

"The core of a quark-filled pulsar would have an overall positive charge" is not an intermediate conclusion, but just a premise. I read Jonathan's post, and it appears to me that he agrees. The last sentence has two parts - the part that opened my post here, and the part starting "it would attract..." The first part is a premise, as you said - it uses "because". That premise, though, is providing evidence for the second part of the sentence. So the second part of the sentence is an intermediate conclusion, or the main conclusion. Jonathan's post shows why it's not the main conclusion, so it's an intermediate conclusion.

I read Jonathan's post again and, as I said, he appears to be thinking along the same lines. I think it's possible you just misread which part he was identifying as the intermediate conclusion.

The main conclusion does not present a new finding. This was discussed earlier in the thread, and Jonathan's post mentions it again. To go over that ground again briefly - the conclusion is not a new "finding" in part because it's not a "finding" at all - the author is speculating that there might be another explanation of the facts. The author hasn't actually discovered anything - it's hypothetical so far, even if it's a plausible hypothesis.

Robert Carroll

[goingslow]

Hi there!

May I ask how would you grammatically break down (C)? And whether (C) is an accurate description of what's going on in the stimulus?

Thank you so much!

[Adam Tyson]

I'm not sure what you mean about the grammatical breakdown, goingslow, but I would say it is NOT an accurate description of what the stimulus is saying. The author never suggests that a quark-filled pulsar would not be recognizable as a pulsar by astronomers. They would still see a spinning ball of neutrons, but they wouldn't necessarily know what was inside it. Like looking at a powdered donut and thinking it's jelly-filled and not knowing that it actually has chocolate cream filling. You still know it's a donut, though.

Sorry, I am just hankering for donuts so that was the first explanation that came to mind!

Mmm, donuts...