PT39.3.19 - "Which can be inferred..." (Passage 3 - Blackbody objects)

Lime Green Dot · June 2021

Link to video expl/quick view: https://7sage.com/lsat_explanations/lsat-39-section-3-passage-3-questions/

My question is about the correct A/C, (A) and an incorrect one, (B).

I interpreted (A) as being far too much of a generalization, since we are only told about thermal radiation, not any other kind (with respect to the passage, we were already made aware that other kinds of radiation exist, as indicated in para. 1: gamma, X-rays, radio, heat, & light).

Had (A) said "radiation reflected by and radiation emitted by an object can be difficult to distinguish from one another," I'd have easily chosen it.

I could also buy that (A) might be a 'necessary assumption' if this were that type of question. Yet I'm struggling with understanding whether or not something that must be assumed to be true in order for certain things to make sense (i.e., why the PHYS had to choose certain types of objects when trying to accurately measure that body's radiation) should therefore be a valid, top-to-bottom inference as well. What allows us to infer something about radiation in general in any object when we are only told information about thermal/blackbody radiation and how blackbody objects relate to that?

I was also actually stuck on (B) for quite a while and hoped to hear some others' thoughts on my analysis. I acknowledge (B)'s relative "strength," compared with (A)--that was surely a red flag.

But I think (B) is ultimately faulted, not because we don't have standards for what is "nearly ideal"--after all, "little or no reflective capability" seems to give us this, but I suppose this could be interpreted as merely 'necessary' and not 'sufficient.' Ultimately, I think (B) is out because there can be an entire range of "dark" that a "dark room" could be, like pitch-black or a room with a thin ray of weak light coming in through the door crack. Since "dark" is not an absolute value, we can't be sure that an object in question in such a room isn't reflecting radiation from other things or surfaces that may be in the "dark room" as well, so we can't assume that object, especially if it weren't itself black, isn't reflecting radiation from elsewhere.

Maybe this is more a question about the passage itself, but I also thought when I was reading para. 2 again that it was reasonable to infer that the author's use of quotation marks at the first mention of "blackbody" radiation was not just use of another terminology we could interchange with "thermal" radiation, but perhaps also indicating to us that an object that could qualify as a blackbody object for an experiment need not itself be black, as long as we could guarantee that it had little-to-no ability to reflect thermal radiation coming from another source. So in other words, I thought the use of the "" could be construed as "so-called," and that it need not be literally a black-colored body in order to be a proper blackbody object, if that makes any sense.

I do acknowledge that "soot" and "black velvet" are black blackbody objects, but I saw these as examples of typical or representative blackbody objects, not necessarily as objects bearing a trait (having a black surface) that must therefore exclude something that could be "made" dark in a pitch-black room. So I guess a follow-up to this is, without reference to outside sources, would this have been a reasonable interpretation of "blackbody" radiation, in the way that the author chose to quote this? Based on para. 2, as much as a blackbody object could itself be black, could we have also reasonably interpreted that any object, whether pitch-black itself or red or green when viewed in bright light, could be a blackbody object candidate in a 100% pitch-black room where, in essence, all things are "black" and there is nothing else there in the room to reflect?

Thanks for anyone's #help on this!

KevinLuminateLSAT · June 2021

@"Lime Green Dot"

Regarding whether (A) is too broad because we only know about thermal radiation as opposed to all types of radiation, the second paragraph says that physicists can be confident that they are observing "thermal radiation and not simply reflected radiation[.]" Thermal radiation was previously defined as "radiation emitted by an object due to the object's temperature[.]" This definition could be interpreted in two ways: (1) there are different kinds of radiation that are emitted by an object, and thermal radiation is the kind of emitted radiation that is due to heat; or (2) thermal radiation is the kind of radiation that is emitted by an object, and heat is simply the mechanism by which such radiation is emitted. Under the first interpretation, your objection does have merit, since we wouldn't know that other types of emitted radiation are difficult to distinguish from reflected radiation. However, under the second interpretation, I think your objection falls away since if thermal radiation is the only kind of emitted radiation, and the reference to it being caused by heat is simply meant to denote how the emitted radiation is produced rather than implying the existence of other types of emitted radiation, then the passage does give us enough to make inferences about emitted radiation. In other words, "thermal radiation" and "emitted radiation" would be interchangeable, and answer choice (A) is not too general, but rather directly captures the passage's distinction between emitted radiation and reflected radiation.

Which interpretation is correct? Speaking without any prior understanding of radiation and based only on my reading of the passage, I'm not sure, but there is other language that suggests the second interpretation makes sense. Consider that the second paragraph says physicists "can monitor the radiation coming from a blackbody object and be confident that they are observing its thermal radiation[.]" So this suggests that the radiation coming from—or in other words, emitted by—a blackbody object is one and the same as thermal radiation from the object, at least when it comes to the kinds of objects that are blackbody.

You may point to the first paragraph's reference to other types of radiation as showing that (A) is too general, but I don't think it proves much. The reference to gamma, X rays, and light doesn't necessarily mean that that these may be among other forms of radiation "emitted" by an object. They could be radiation produced through some reaction or through some other process that doesn't count as "emitted" radiation. So the first paragraph doesn't help us decide which interpretation to go with.

What are your thoughts on this? (I'll try to respond to your other questions later when I have the time to address them well.)

canihazJD · June 2021

Concur with Kevin, but I'd also suggest that even under the offending interpretation, in other words, either way you read it, (A) is still absolutely correct because the stem asks for the one that is "the most clearly inferred," as opposed to "clearly inferred." The other answers are unsupported IMO.

Regarding B: if this was attractive I think we need a bit more clarity regarding what makes a BBO ideal. For me a good run at this question would involve reading B and articulating this, then comparing that to what you get from a dark room. A dark room is dark because there is no light in it. A BBO is dark in color because it reflects little light regardless of surrounding light. Its non-reflectivity is what makes it a good BBO... the radiation you measure is the objects own. Simply putting any object into a dark room doesn't change its reflective capacity.

Plus the AC says "any object." So like a Tesla, my dog, a bag of Chipotle, and a bottlenose dolphin? Let's consider an object that would be a terrible BBO... maybe a chrome ball... that somehow is undergoing massive thermal fluctuations... surrounded by randomly angled double sided mirrors... lit on fire... or something like that. Or maybe a 360 degree reflective flood lamp that is turned on, both generating and reflecting heat and light. All we have to do is put these things into a dark room to make them a nearly ideal BBO? I don't think so.

Lime Green Dot · June 2021

Thank you both so much for taking the time to reply!

@KevinLuminateLSAT , I was definitely of the mindset you described in interpretation (1)--that thermal energy is, or at least could be, but one of several kinds of radiation that is reflected/emitted by an object. I therefore didn't see this interpretation as being inconsistent either with the definition of thermal radiation or the statement about the PHYS's accuracy of radiation measurements in the presence of a BBO. I agree that if interpretation (2) is the one we are supposed to take, well, (A) not only manages to scrape by, but can actually be quite strongly and clearly inferred!

Here's where I still have questions. You say that (2) might be the interpretation we were intended to make that could thus lead us to (A). Your support is the line that says physicists "can monitor the radiation coming from a blackbody object and be confident that they are observing its thermal radiation[.]" A potential problem I see here is one that you already referenced--yes, PHYS could be confident about the kind and source of radiation they were measuring when it comes to the kinds of objects that are blackbody. But now I feel we are nearly back at square one: Are we to suppose that BBO = objects in general ([A] says 'an object' not just 'blackbody objects'; this, I interpret to mean objects in general) from a statement that seems to just be talking about BBO? If yes... well, then we can perhaps assert that the radiation reflected/emitted = thermal radiation alone, and not any others that exist. The matter is settled, and (A) would be right without question. But I just don't see how lines 19-22 really give us the textual support we need to opt for this latter interpretation. I also agree that the mere existence of other kinds of radiation mentioned doesn't do anything to support the notion that other kinds of radiation could be emitted. I mentioned it more as the context or footing we'd need to begin to mount a legitimate counter to (A). We at least have knowledge that there are other kinds out there. At the same time, the existence of other kinds of radiation, and the author choosing to let us know about these, doesn't of course go against the possibility that other types of radiation could be emitted by an object either. So now I feel caught between a rock and a hard place trying to decide b/w these two, haha.

canihazJD · June 2021

But I just don't see how lines 19-22 really give us the textual support we need to opt for this latter interpretation.

Mm... keep hammering this out I guess since its a good exercise, and hopefully Kevin can give a different perspective, but IMO you don't need support to opt for that interpretation. You could interpret it either way, or literally change the passage to reflect either interpretation more clearly, or you could just take the text as is at face value and the answer would be the same. You don't need strong support, nor do you need a good answer here. This isn't a MBT question. You just need to identify the least worst one... A is actually decent, and the rest are pretty bad.

We use BBOs because they do not reflect radiation, allowing us to know that we are measuring the object's emitted radiation. If we could easily tell the difference between emitted and reflected radiation of a given object, why would we need BBOs? I don't see how any of the other stuff matters... find less to worry about.

Lime Green Dot · June 2021

Whew, started this response yesterday, but just now finishing!

@canihazJD, I did note that we were being asked to draw out the "most clearly" inferable statement. I don't disagree that the other A/C just don't cut it. My issue was more with the A/C itself rather than realizing there was nothing else but (A) to pick. I acknowledge we've gotta allow for some less than ideal answers sometimes, which naturally tend to be more on the "strongly implied" rather than the "explicitly stated" side. But I just didn't feel that (A) passed the minimum threshold of being "strongly implied" for the reasons I mentioned. My biggest problem with (A) is its use of "are" rather than "can be difficult to distinguish." Can an A/C be both necessary (I think A does fall into this category--or maybe it just strengthens), yet not, strictly speaking, something that "can most clearly be inferred"? I'm not sure why, but in my mind it felt like at least for this question, these two worlds were divided. It felt like if (A) were true, I feel it gives purpose and meaning to why the PHYS needed to carefully pick out their BBO (so it strengthens, I guess?), but it need not be true of all kinds of radiation. Sorry for being reiterative, but I just can't resign myself to saying (A) can be most clearly inferred when it feels like quite a stretch to claim. I can't name any off the top of my head, but if I started keeping track, I'm sure I could find at least a few MSS/Inference Qs on these RC passages where a wrong answer in a vid explanation was lambasted with a "yeah, and how are we supposed to have any idea about that?" or "Just b/c "X" (what's stated in the passage) doesn't mean "Y" (unsupported inference)." I dunno, I think I'm probably overthinking this, but isn't it a bit of a double standard for the LSAT writers to invite us to do this time but shun us to do at other times? Again, probably overthinking, but I'm trying really hard to grasp some reliable standard I can refer back to when I approach such questions as these and feeling like it's slipping through my fingers like water just as soon as I think I've "got it."

Or maybe a 360 degree reflective flood lamp that is turned on, both generating and reflecting heat and light.

Yeah, I'd wondered if an object that was glowing could be counted as part of "any object" in a "dark room" since my thought initially was that the glow (or any source of the object's light) would not render the room dark any longer. But if we can have an initial state of a dark room, and it's merely the object itself that reflects/emits radiation, then yes, a glowing, reflective, fluorescent thing doesn't seem like it would be 'nearly ideal,' let alone ideal at all. I think I was confusing the kind of reflection that can be seen with the kind of reflection that can be felt (that's why I thought the black-color issue could be addressed if a dark room weren't just dark, but pitch-black dark).

Plus the AC says "any object." So like a Tesla, my dog, a bag of Chipotle, and a bottlenose dolphin?

This might be completely ludicrous, but honestly, I didn't know and didn't want to assume. What if we had a completely black Labrador retriever in one pitch-black dark room versus a golden Labrador retriever placed in another, equally pitch-black dark room? Could they both be 'nearly ideal' BBO? Neither? Can only inanimate objects be good BBO? Based on the definition you referenced from the passage, "A BBO is dark in color because it reflects little light regardless of surrounding light. Its non-reflectivity is what makes it a good BBO"--it wasn't all that clear to me whether or not something like a bag of Chipotle in a dark room (by your definition, a room with absolutely no light) or a golden or black Labrador might all be equally good BBO candidates in that completely dark room, if they were each the only thing there. B/c without light, how can anything 'reflect'? In my mind, I also picture the "any object" in the dark room in (B) to be there in isolation--but maybe this is part of an assumption that's not okay to make?

Thank you again!

canihazJD · June 2021

@"Lime Green Dot" said:
..."strongly implied" rather than the "explicitly stated" side. But I just didn't feel that (A) passed the minimum threshold of being "strongly implied" for the reasons I mentioned.

Remember these are our constructs we apply to the content because it makes us more efficient and it works... most of the time. The test writers are under no such constraints.

My biggest problem with (A) is its use of "are" rather than "can be difficult to distinguish."

A bigger jump yes, but still a reasonable one IMO. If they were not difficult to distinguish what would be need BBOs for?

Can an A/C be both necessary (I think A does fall into this category--or maybe it just strengthens), yet not, strictly speaking, something that "can most clearly be inferred"?

Definitely... since most clearly inferred implies a comparison between answer choices.

...but I just can't resign myself to saying (A) can be most clearly inferred when it feels like quite a stretch to claim.

Thats the thing though... we can have a very very bad weaken, strengthen, or incredibly unsupported inference that will still be the correct answer, as long is it moves the needle the most or has the most support. A stretch is absolutely allowed, and is in fact their go-to tactic on harder comparative answer choice selections.

I can't name any off the top of my head, but if I started keeping track, I'm sure I could find at least a few MSS/Inference Qs on these RC passages where a wrong answer in a vid explanation was lambasted with a "yeah, and how are we supposed to have any idea about that?" or "Just b/c "X" (what's stated in the passage) doesn't mean "Y" (unsupported inference)."

There definitely are and thats ok. Just remember it is a comparison. It is completely likely, on a harder question, to say "Just b/c "X" (what's stated in the passage) doesn't mean "Y" (unsupported inference)" the first time through, but then end up not selecting anything, requiring you to go back and determine basically which one sucks the least. At the same time, if an answer is not supported at all, it cannot be the one that is "most" supported, which allows us to get rid of some answers quickly and confidently. It just takes some comfort with the mechanics of these comparative AC questions.

I dunno, I think I'm probably overthinking this, but isn't it a bit of a double standard for the LSAT writers to invite us to do this time but shun us to do at other times? Again, probably overthinking, but I'm trying really hard to grasp some reliable standard I can refer back to when I approach such questions as these and feeling like it's slipping through my fingers like water just as soon as I think I've "got it."

...I'd wondered if an object that was glowing could be counted as part of "any object" in a "dark room" since my thought initially was that the glow (or any source of the object's light) would not render the room dark any longer.

"Any object" is pretty clear IMO, but we can simplify this by just saying whatever the least ideal BBO is... let's put that in a dark room. Does it then become nearly ideal?

...B/c without light, how can anything 'reflect'? In my mind, I also picture the "any object" in the dark room in (B) to be there in isolation--but maybe this is part of an assumption that's not okay to make?

It's not whether there is actual reflection of radiation going on or not, but the capacity of the object to reflect... specifically heat, not light. Light (or absence thereof) wouldn't affect thermal reflection/emission unless light was the actual source of the heat. If I put a heated object into a dark room, it continues to radiate, just as a conductive object continues to conduct, and a reflective object continues to reflect. In this AC they are pushing you to conflate the "darkness" of a BBO and/or the reference to reflectivity with light (the darkness of a dark room), when we are talking instead about thermal energy. Can the two occur at the same time or cause each other? Sure but they don't have to, and there is no indication that light has anything to do with paragraph 2.

I think a lot of this is you just getting in your own way here. I'll circle back to saying I don't think most of this stuff matters for this question. This should be the focus:

Is there support for A? I would say yes - If reflected and emitted radiation were not difficult to distinguish from each other, we wouldn't need special objects that don't reflect to measure emitted radiation. Is it an airtight answer? No, but it doesn't have to be. It doesn't have to be true... just the most reasonable (which could include something unreasonable) or most likely (which could be something unlikely).

Is there support for any other answer? I would say no, making A the obvious choice.

If you can agree on those two issues, then there is no more work to be done on this question, because honestly you're asking things that go beyond the scope of the passage and the mechanics of the question. I'm not saying that in a negative way... like just literally, you weren't given the information to resolve those things. Remember that while it definitely helps, understanding the content isn't our goal. Our goal is to get the point for that question... by whatever means necessary. On test day you absolutely will not have the time to attack at this depth, and even if you did, it'd be pointless because you'll have dug way past the question anyway. And once the test is done, the content will effectively cease to exist for you. You will likely never see it again, and never know if you understood it or not.

Lime Green Dot · June 2021

@canihazJD, yes! Thanks for all of this. I am that person (probably you can tell by the length of my posts) that often gets bogged down by details. Sometimes knowing them helps. Oftentimes it elucidates things in an fyi way, for my own benefit, and while it might help with comprehending the passage itself for me, beyond that, this extended understanding or having answers to some of my questions just doesn't often serve me well for the purpose of getting that test point--and of course, that's the end goal. Will try to bear this in mind going forward, but it's a psychological struggle sometimes finding that right level of understanding that's enough to push onward.

Remember these are our constructs we apply to the content because it makes us more efficient and it works... most of the time. The test writers are under no such constraints.

That is so true... I do tend to forget that as well.

Definitely... since most clearly inferred implies a comparison between answer choices.

Can we take this a step further and say that because (A) is necessary for the content of para. 2 about the BBO to make sense, is it thereby inferable? In other words, the negation of (A) would render para. 2 pretty nonsensical I think, so I wondered if this were the key to seeing why (A) is not only inferable but necessary for the para. to function in its assertions about BBO.

Just remember it is a comparison...At the same time, if an answer is not supported at all, it cannot be the one that is "most" supported...

...honestly you're asking things that go beyond the scope of the passage and the mechanics of the question...Remember that while it definitely helps, understanding the content isn't our goal.

Right. My confusion was in comparing whether (A) had relatively more support than (B). But trying to figure out whether (B) had more, less, or any support did lead me down the unfathomably deep rabbit hole (just in BR, as I thought about this A/C more and more) of asking all those tangential/superfluous questions about reflectivity, an object's inherent fluorescence, whether the BBO object in question in (A) was a solitary object in a dark room, etc.

If I'm understanding your pointers correctly, I think I can make a little guidepost out of this to help me along: Given a choice b/w a path that's more convoluted (making us ask more questions than can be strictly answered from the text) on a less-or-unpaved surface (i.e., having less or no concrete 'support') vs. a path that's a 'stretch' but a relatively unobstructed one, taking the less obstructed one is the way to go, as long as and even if it has a single, solid brick of paving to support it.

canihazJD · June 2021

@"Lime Green Dot" said:

Can we take this a step further and say that because (A) is necessary for the content of para. 2 about the BBO to make sense, is it thereby inferable? In other words, the negation of (A) would render para. 2 pretty nonsensical I think, so I wondered if this were the key to seeing why (A) is not only inferable but necessary for the para. to function in its assertions about BBO.

Yes. In fact, one popular way to look at NAs are as MBTs. By definition, they must have occurred in the world of the argument. Here its not quite as airtight but same principle.

My confusion was in comparing whether (A) had relatively more support than (B). But trying to figure out whether (B) had more, less, or any support did lead me down the unfathomably deep rabbit hole (just in BR, as I thought about this A/C more and more) of asking all those tangential/superfluous questions about reflectivity, an object's inherent fluorescence, whether the BBO object in question in (A) was a solitary object in a dark room, etc.

I'm not sure if its always intentional on their part but that does happen. Every time it happened to me, the ultimate resolution was that I realized I'd gone beyond anything that mattered for the question and was kind of just chasing my own tail. B has two unrecoverable issues - "any" object is clearly not supported, and it pushes you to conflate light with the discussion in p2, attacking your understanding of the BBO concept. I think the latter was intended in part to mask the former.

If I'm understanding your pointers correctly, I think I can make a little guidepost out of this to help me along: Given a choice b/w a path that's more convoluted (making us ask more questions than can be strictly answered from the text) on a less-or-unpaved surface (i.e., having less or no concrete 'support') vs. a path that's a 'stretch' but a relatively unobstructed one, taking the less obstructed one is the way to go, as long as and even if it has a single, solid brick of paving to support it.

I think thats a fair summary. Often the right choice will be a terrible one... just the least terrible. You can't let that lure you into "helping" other answers work. That single brick of support ended up being the only support in the entire selection. To carry the analogy further, you want a brick that is already placed... not a place where a brick could theoretically go.

Lime Green Dot · June 2021

Thank you so much as always, @canihazJD! You phrase those lessons we ought to know, and probably for the most part do know yet amazingly forget or stubbornly fail to apply, in a way that really hits home.

Just one final follow-up on looking at NAs as MBTs... While NAs must be MBTs, does it have to be the case that MSSs (the kind that requires a bit of a 'stretch' as in this question) are NAs? Or is it just coincidental that in this case, the MSS is also an NA? Is this question perhaps an MBT in MSS clothing?

My guess is that for any MBT inference, it is an NA and vice versa. But if it falls anything short of an MBT, yet is an MSS, it may not need to be an NA. I think maybe I answered my own question haha...

But this question stem ('Which of the following can most clearly be inferred...') seems to indicate that this is a case of MSS (the kind that's not ironclad) = NA b/c of what happens if we run the negation test... the content of para. 2 just becomes a bit pointless.

At the same time, I don't know if this 'pointlessness' is the same thing as saying that the para. 'falls apart' or is severely 'weakened' in the same way we would when we apply a negated assumption to an ARG and thereby determine it's necessary.

Howdy, Stranger!

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PT39.3.19 - "Which can be inferred..." (Passage 3 - Blackbody objects)

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