#13 - One of the effects of lead poisoning is an

[vbkehs]

This question was a "Van No" for me - I chose D during the practice test, then C upon review... and am completely blindsided by the correct answer choice A. I struggled to choose any answer choice, and negating D seemed to weaken the conclusion most for me. The negation I made was: "The paints Van Gogh used in the "Sunflowers" paintings had toxic ingredients other than lead." which I thought weakens the causal argument in the conclusion. If he could have been suffering from other toxic ingredients, we cannot conclude that he suffered from lead alone, so D makes sense.

WHERE in the world does A come from? And where am I going wrong in my reasoning? Thanks in advance!

[sneeze]

Hey vbkehs! i came out here with a similar question as you. def take my thoughts with a grain or two of salt as I am also just a student. I also picked D originally, but i realize now that the reason why D doesn't kill the conclusion when negated is because the conclusion is specifically about how lead poisoning affected VG's eyesight. So even if there were other toxic chemicals in the paint that he could have been ingesting, and even if those other toxic chemicals were also affecting his optic nerve, you're right that this only weakens the conclusion. But we need an answer that, when negated, totally obliterates the argument. And D doesn't do that

So the reason why I was originally eliminated A was because it didn't match my prephrase ("what if the halos were actually there and VG wasn't imagining them?")
When I read A, I was like oh, if he was painting things as he saw them, then that means that the halos were actually there because what he saw was real and he wasn't imagining it. I totally just disregarded this answer because it seemed to be saying that the halos were actually there, which I thought weakened the original argument.

I realize now that I totally misread A. If VG was painting things as he was seeing them, then that means he was seeing halos.
I think when negated, A would read as "in VG's later painting he never painted things as he saw them". This would mean that whatever he was seeing, he wasn't painting. It's not immediately clear to me that this, in the negated form, kills the argument. But when you say to yourself "ok if he was never painting things as he saw them, then he was never seeing halos, which means his optic nerve was not damaged, which means he was not suffering from lead poisoning", and that kills the argument. {the part in pink is the part that I am the most iffy on}

i hope that makes sense, and I'm sorry if I confused you more! and @powerscore staff PLS let me know if i've totally botched this and i'm totally wrong!!

[Jeremy Press]

Hi vbkehs and sneeze,

The explanation sneeze offers is on exactly the right track (nice job, sneeze!) but I want to reframe it just a little.

The argument's conclusion is that Van Gogh was suffering from lead poisoning, which means the author is assuming that Van Gogh was in fact experiencing the "halo vision" effect of lead poisoning. What evidence do we have that Van Gogh was in fact seeing halos? Only the author's premise that Van Gogh painted halos. So what the author is assuming is that Van Gogh was painting halos because that's what he was in fact seeing!

That assumption isn't a very good one, because not only is it possible that someone paints something other than what they're actually seeing, I think that happens all the time. Painters paint things they imagine, not things they necessarily see (if not, I bet some eye doctors would LOVE to know what the heck was going on with Picasso's vision, for example). That's how I would attack the argument: Van Gogh painted halos not because he saw them, but because he thought they made his painting "pop!" Answer choice A defends against that attack. It confirms that at least some of the things Van Gogh painted (the halos) were things that he was in fact seeing.

The reason answer choice D isn't a correct one is that it's not specific enough as to the precise type of toxicity of the substances. It could be that the paint Van Gogh used had substances that were toxic in ways other than inflaming the optic nerve (maybe things that cause temporary paralysis, or throwing up, or shortness of breath), in which case the conclusion wouldn't be affected at all. So for answer choice D to be an assumption, it would need to tie the substances it mentions more tightly to the specific "inflammation of optic nerve" effect that lead causes.

I hope this helps!

Jeremy