“Layering” in Critical Reasoning Questions
In CR, you are given an argument and asked to evaluate its logic. This requires an ability to understand how the author supports his main point (the conclusion). Does the author use persuasive evidence? Are there gaps in the logic? The more information you have to sort through, the more difficult it is to determine whether the argument hangs together.
But each argument must start with a conclusion and at least one piece of evidence that the author thinks will justify the conclusion. Let's take a basic example:
Some people have died after ingesting cyanide.
Therefore, cyanide is deadly.
Is this a persuasive argument? Not really. The fact that some people have died after ingesting cyanide is not, by itself, enough to prove that the cyanide was the cause of their deaths. This gap in logic is readily apparent, so the test writers need to add information to divert your attention away from the faulty logic. For example,
At a certain party, some people drank wine laced with cyanide and some drank unadulterated wine. Those who drank the laced wine subsequently died. Therefore, cyanide is deadly.
Does the new information close the gap in logic? Not really, though it does make the gap less obvious. After all, if the people who drank the cyanide all died, the cyanide must be deadly, right? And the comparison between those who drank the cyanide and those who did not seems compelling as well, at least until we realize that we do not know what happened to those who drank the unadulterated wine. The author clearly wants us to believe that they survived, but for all we know they died, too. So while all the new information seems to support the conclusion, what proof is there that the cyanide was the actual cause of the deaths? The flaw can be further disguised:
History has shown that cyanide can be classed as a deadly toxin. In one famous episode, for example, Lucrezia Borgia, notorious poisoner of sixteenth-century Italy, once served cyanide-laced wine to several of her political rivals at dinner, while serving unadulterated wine to her cronies. Within seconds, those who had ingested the cyanide were all dead in their seats.
Here, a narrative leads you away from the thread of logic. There is still no way to know that cyanide was actually responsible for the deaths. We can conceive of other explanations for their deaths, even if cyanide poisoning seems the most likely. However, the presentation of information makes this flaw recede into the background while the narrative comes to the fore. Putting the conclusion at the beginning of the argument also helps mislead the reader. But if we strip away the narrative, we are left with the original argument:
Some people have died after ingesting cyanide.
Therefore, cyanide is deadly.
As you read CR texts, you must strip away all the distracting layers to get to the core of the argument: conclusion and necessary evidence. Everything else is there to mislead you.
Major Take-Aways
- When studying, try to figure out how the author “layered” the sentence to make it more difficult. Can you write a simpler version of the sentence (perhaps with only the core information, not everything)? How did the author make this sentence so tricky?
- If you can split out the core and understand how the different pieces of “extra” info fit into the core, then you won’t be as likely to fall into a trap on a “layered” question. (You still might fall into a trap – but you will have a much better chance of avoiding it!)
