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

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.

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.

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 [Van Gogh] 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

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