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Flaw in the Reasoning. The correct answer choice is (A).
This problem is one of the hardest in LSAT history, and holds a position on our list of The 15 Hardest LSAT Logical Reasoning Questions of All Time.
The difficulty arises in part from the lengthy, multi-part nature of the stimulus, but more so from the brutally tricky-to-understand correct answer choice. Sitting in first position at (A), it's an answer both difficult to understand and easy to dismiss since it seems at first glance to be unrelated to the argument. With that in mind, let's review the argument.
The argument opens with the contextual fact that until recently it was believed that inks prior to the 16th century did not contain titanium. But, now there is a new type of analysis, and it has detected titanium in two different Bibles: Gutenberg's and the B-36 (though not in any other book from the 15th century). At this point, the argument seems fairly straightforward: a new test has discovered titanium in the ink of two Bibles that they thought didn't have it, but not in any of the many other books tested.
With this background information, the author moves on to conclude that this is of great significance since it shows that Gutenberg printed the B-36 and that the presence of titanium in the Vinland Map is no longer a reason for doubting it's authenticity. But wait a second, what's this new information about the Vinland Map? The author sticks this new info in, and it's initially confusing for most people. In this case, the Vinland Map had apparently been thought not to be authentic since it contained titanium in it's ink. Now the author is claiming that since this new test found titanium in the two bibles, that the Vinland Map is no longer suspect either. Essentially, the author uses the titanium information to draw the two-part conclusion that the B-36 Bible was printed by Gutenberg and that the Vinland Map is really from the 15th century.
The question stem is a Flaw in the Reasoning, and this presents confusion for most students, who read the stimulus without thinking there was an error of reasoning present. In a problem this difficult, do not be alarmed if you missed the issue!
So, what happened here that was problematic? As Kelsey Woods says below, "The flaw in this argument is that the author is using the rareness of titanium in the ink of 15th century texts to strongly support that the B-36 Bible was printed by Gutenberg but they are also using the presence of titanium in the ink of the Vinland Map to support that it was printed in the 15th century. This presents a contradiction. If titanium in ink in the 15th century was widespread enough that it's presence cannot be used to say that a document was not printed in the 15th century, then the use of titanium in ink would not be enough to trace a book back to a specific printer. On the flip side, if the use of titanium in ink in the 15th century is rare enough to trace a book back to a specific printer, then it's use is not widespread enough to support that other 15th century texts might have used titanium ink. Answer choice (A) describes this flaw so it is the correct answer."
Answer choice (A): This is the correct answer choice. As explained above, the author tries to use the presence of titanium in the ink to show it's rarity means Gutenberg printed a certain bible and also that it's common enough to prove the Vinland Map is authentic. you can't have it both ways, and that's the flaw here.
Answer choice (B): Again, let's reference Kelsey's excellent explanation from below: "Answer choice (B) is incorrect because this argument does not depend on the printers and artists of the 15th century knowing whether or not their ink contained titanium. Whether they were aware of the presence of titanium in their ink or not, the titanium would still have been there and it's presence was either rare enough to be able to trace specific books back to a specific printer or widespread enough to make the presence of titanium not enough to rule out something as having been printed in that century."
Answer choice (C): The questions to be asked of this answer are two-fold. First, in general, would it be unreasonable to think that "determination of the date and location of a document's printing or drawing can be made solely on the basis of the presence or absence of a single element in the ink used." And the answer is that it is probably not unreasonable in a general sense. If Gutenberg had been the only person in the world using titanium in his inks, then perhaps there would be a way to pin down broad dates and times. Let's set aside that point though.
The second question here, then, is more specific: does this argument attempt to actually determine "the date and location of a document's printing or drawing"? And in the specific, I'd say no, that does not happen. The author uses the titanium element to tie things together and make broad conclusions, but nowhere is there a specific date or exact location given for these items. Since this latter part isn't occurring, this answer is incorrect.
Answer choice (D): The author doesn't venture into discussing the aesthetics or merits of either the B-36 Bible or the Vinland Map, and thus it would be difficult to criticize the author on these grounds.
Answer choice (E): Let's refer to Adam Tyson's explanation from below: "A Flaw in the Reasoning answer has to be true, by which I mean it has to describe something that actually occurred in the stimulus. In addition, the answer has to be some sort of a problem that would hurt the argument and make the author say "oops, my bad, I should have thought of that." Let's analyze answer E in light of that two-part test. If it fails either part, it's a wrong answer.
Is it true that "the discovery of titanium in the ink of the Vinland Map must have occurred before titanium was discovered in the ink of the Gutenberg Bible and the B-36 Bible"? It certainly seems that way from the way the stimulus is written. The titanium in the ink of the two bibles was recent, thanks to the new type of analysis, and it seems like the Vinland Map's titanium ink has been known for a while and has been the source of doubts about its authenticity. So this answer does appear to pass the first test for a good Flaw answer.
Now the second test: is that a problem? Would our author hang his head in shame and say "oh darn, I really messed that up, sorry, please forgive me for being so wrong."? Or would the author say "well yeah, the titanium ink was discovered in the Vinland map a long time ago, and that's why we doubted that it was authentic, but new information has us rethinking that. So what, what's your point?" I think the latter is the more likely reaction - so what if the titanium ink in the map has been known about for a while longer than the ink in the bibles? That does no harm to the conclusion that maybe the map is legit after all, and that we should stop doubting it.
Having failed the second test, answer E is not a good Flaw answer, and we can toss it away. No problem, so not a flaw!
Try that two-part test on your contenders to Flaw questions in the future and see if it helps you sort out the good ones from the bad a little easier."
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