One of the effects of lead poisoning is an inflammation of the optic n

Question

One of the effects of lead poisoning is an inflammation of the optic nerve, which causes those who have it to see bright haloes around light sources. In order to produce the striking yellow effects in his “Sunflowers” paintings, Van Gogh used Naples yellow, a pigment containing lead. Since in his later paintings, Van Gogh painted bright haloes around the stars and sun, it is likely that he was suffering from lead poisoning caused by ingesting the pigments he used.

Which one of the following is an assumption on which the argument relies?

Which one of the following is an assumption on which the argument relies?

(A) In Van Gogh’s later paintings he painted some things as he saw them.

(B) Van Gogh continued to use paints containing lead after having painted the “Sunflowers” paintings.

(C) Van Gogh did not have symptoms of lead poisoning aside from seeing bright haloes around light sources.

(D) The paints Van Gogh used in the “Sunflowers” paintings had no toxic ingredients other than lead.

(E) The effects of Naples yellow could not have been achieved using other pigments.

ChrisLele · Accepted Answer

Interesting question!

Let's imagine, for a moment, that we are Van Gogh. Let's also imagine that we are afflicted with lead poisoning and, as a result, perceive haloes around light sources (as the argument asserts).
We look up at the sky at night and the stars have haloes around them.

In such an instance, we are assuming that we painted what we literally saw. And so the argument hinges on this fact - that Van Gogh painted what he perceived.

If Van Gogh did not have lead poisoning, and thus did not perceive any halos around the stars, then he consciously added haloes to the painting has an effect. Were this the case, the argument falls apart - Van Gogh didn't have lead poisoning, he simply decide to paint haloes.

aditya8062 · Answer

A seems viable :  In Van Gogh's later paintings he painted some things as he saw them.

MENTION THE SOURCE AND THE OA

JackPack · Answer

Given: lead poisoning is an inflammation of the optic nerve, which causes those who have it to see bright haloes around light sources. 
Also given: Van Gogh painted bright haloes around the stars and sun
Conclusion: Van Gogh must have painted some paintings as he sees, because normal (other) people don't see bright haloes around stars and the sun.

Tarungaur · Answer

AndrewN

Hi Andrew, could you please clarify a dobut in answer option D. Option D can be eliminated on the basis of the fact that the same mentions a particular  sunflower painting  whereas the conclusion provides a general notion that Van Gogh was suffering from from lead poisoning.

Thank you.

AndrewN · Answer

Hello,  Tarungaur . Perhaps because I am more interested in fine art, and undoubtedly because I have had tons of practice on CR-style questions, this one proved straightforward for me, and I answered confidently (and correctly) in under a minute and a half. I will provide an analysis of the answer choices below, making sure to touch on your concerns in (D).

To be honest, when I read the argument— it is likely that   was suffering from lead poisoning caused by ingesting the pigments he used —the word  ingesting  stood out. I was thinking,  Now, how did he go from using the paint to eating it?  I even reread the first line to check whether  ingesting  might extend to some sort of  intake  of a toxin through the eyes, but to no avail. As you may know from my posts,  I do not "pre-think"  with CR or any other type of question, even if I can appreciate its usefulness to some.  Nor do I use the negation technique  on assumption questions. It is just my preference. I like to leave the answer choices just as they are and to see whether I can create a logical bridge between premise(s) and argument using, more or less, a mental drag-and-drop method. I will explain below.

Yes, this  must  be true for the argument to hold. Here is how we can check:

Background —one of the effects of lead poisoning... causes those who have it to see bright haloes around light sources... in his “Sunflowers” paintings, Van Gogh used Naples yellow, a pigment containing lead

Premise —in his later paintings, Van Gogh painted bright haloes around the stars and sun

Assumption —in Van Gogh’s later paintings he painted some things as he saw them  √

Argument —it is likely that he was suffering from lead poisoning caused by ingesting the pigments he used

There is a seamless flow of logic from beginning to end with the assumption tucked into the right place. There is nothing to argue with here.

We have no idea, based on the passage, what types of paints Van Gogh may have used to execute anything other than  his "Sunflowers" paintings , nor are we provided any information on how much exposure to lead may lead (eventually) to lead poisoning, so we cannot assess whether further exposure to or ingestion of lead-based paint could have played a role in this "halo effect" in later paintings by the artist.

This one is simple: If the argument is based on  bright haloes , then the assumption should relate in some way to these bright haloes, not to some other effect of lead poisoning.

Now, to address your earlier query. The paints and the series of paintings are correct. We are not talking about some other mystery paints or paintings, as in (B) above. But the problem starts with this speculation about other  toxic ingredients . How do we know what effects  other  toxic substances may have, based on the passage? There is no such information to be found. Keep it simple. If the argument is based on lead poisoning and the passage provides information on the effects of lead poisoning, then a  necessary  assumption will not toss something else into the mix that could or could not be true. Think about it. Does the presence of other toxic ingredients affect the argument?

1) There were other toxic ingredients in the paints—It could still have been the lead that led to Van Gogh seeing and painting bright haloes, and the argument would hold.

2) There were no other toxic ingredients in the paints—The lead still may not have caused lead poisoning, but the argument seems more reasonable.

In short, we can rule out (D) because the passage is not concerned with  any  toxic ingredients in paint other than lead, so we should not be either.

Like the previous answer choice, this one places an entirely different consideration in front of us. The argument runs that Van Gogh suffered from lead poisoning from  the pigments he used —Naples yellow being one such color. We can only wonder what could have happened with  other pigments .

Perhaps the question and answer choice (D) specifically make more sense now. Thank you for thinking to ask, and good luck with your studies.

- Andrew

DonBosco7 · Answer

Had a hard time negating A, can someone please explain how to negate A........ i picked option D, however i do understand why option D is wrong, because this option only mentions about the "sunflowers" painting but the argument has also mentioned other paintings in addition to sunflowers painting. !

One of the effects of lead poisoning is an inflammation of the optic n

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One of the effects of lead poisoning is an inflammation of the optic n

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