Must Be True EXCEPT V. Cannot Be True

[dsamad]

Hi there,

I have been encountering some difficulty in distinguishing between the MustX question type nad the Cannot Be True question type. I read the previously posted questions on this matter and understand that there has been some discrepancy in the answers provided in the RC Bible. Are those also in the 2019 bible? But I still do not understand the difference in essence, whether the difference in the Q stem layout or in looking for an answer for each of those question types on RC. Any help clarifying the nuances to better distinguish between the two would be much appreciated.

Thank you!

[Adam Tyson]

The stem to any EXCEPT question always describes the four wrong answers, dsamad. In a Must Be True-Except question, the four wrong answers Must Be True, and the correct answer will be the logical opposite of that, which is Not Necessarily True (aka Could Be False). So you should be looking for an answer that could be false, even if it doesn't have to be false.

For a Cannot Be True question, you are looking for exactly that - something that Cannot Be True (aka Must Be False). The four wrongs answers in that question will be the logical opposite - Could Be True.

So the difference is in the MustX, the right answer could be false, but doesn't have to be. It's just POSSIBLE that it is false. But in a Cannot Be True, the correct answer absolutely MUST be false, no room for doubt. It's guaranteed to be a false statement. Think about those stems, what they describe, and what the logical opposite of that statement is, and that should help you keep things straight!

[dsamad]

Thank you for your reply Adam! I probably would be able to recognize the difference in LR more than RC just due to the fact that the latter is longer with more details and thus deciding what could be false or could be true is more difficult. COuld you please offer more illustration on the language used in the Q stem of each of those two types? I feel I am still not there yet in recognizing when a questions is one from the other.

[Paul Marsh]

Hi dsamad! Adam's last paragraph above does a very nice job explaining the difference in what we're looking for with the two question types. Just to reiterate - for Must be True EXCEPT, the correct answer choice will be something where we're not sure whether it's true or false. For Cannot be True, the correct answer choice will be something where we're sure it must be false.

As for the question stems, each of these two questions types will typically be very clear what they are looking for. So the most common question stem for Must be True EXCEPT questions is simply: "Each of the following must be true EXCEPT". Or sometimes you'll see a close variant thereof such as "All of the following can be properly inferred from the information above EXCEPT:" For Reading Comprehension in particular, a question stem might look like: "The passage supports that the author would agree with each of the following EXCEPT." Here's a stem I found from the RC section of the December 1999 LSAT, question #5: "The passage provides information intended to help explain each of the following EXCEPT." Here's another one from the RC sectino of June 1992, question #12: "The passage supports all of the following statements about the differences between Gombrich and Radford EXCEPT:". So if the question stem is asking in some form or another which of the answer choices are supported by the stimulus "...EXCEPT", then you know you've got a Must be True EXCEPT question on your hands.

The most common Cannot be True question stems are: "Which of the following must be false", or "Which of the following CANNOT be true". But another somewhat common Cannot be True question stem is: "Each of the following could be true EXCEPT". I suspect that maybe that last stem example is one that you may sometimes mix you up. But don't let the word "Except" there confuse you - a "could be true EXCEPT" question stem is NOT the same as a Must be True EXCEPT; a "could be true EXCEPT" question stem is the same as a Cannot be True question. Why? Because the question stem is telling you that all the wrong answers "could be true", while the correct answer is something that "cannot be true". Whenever you see "could be true EXCEPT", it may be helpful to immediately translate that to "cannot be true" in your head.

Hope that helps! Feel free to follow up if you have any more questions.