Could be true and not necessarily true

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Could be true and not necessarily true

What is the difference between these question types?

I am confused since both appear to be equivalent to me. Can you go over these definitions?

[Dave Killoran]

Hey Pacer,

Can you remind me of what materials of ours you have? that will tell me where to send you for the answer to this question (which is explained in detail), as well as a few others you have posted

Thanks!

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I have LR and LG books

[Dave Killoran]

Great, thanks! We actually go into more detail in the courses on this topic, but given what you have, first reference page 337 and read through the Logical Opposition section (and when reading that section, keep in mind that Could be True is like Some, and Not Necessarily True is like Not All).

Next, Could be True and Not Necessarily True are both quite similar and quite different! If we were to use the Constructs that appear in the LRB and use a "truth" scale of 0-100, we'd see something like this:

• Truth
  
  Must Be True = 100 (all of the truth)
  Not Necessarily True = 0 to 99 (everything but Must Be True)
  
  Could Be True = 1 to 100 (everything but Cannot Be True)
  Cannot Be True = 0 (none of the truth)

Using those definitions, Could and Not Necessarily look really similar—they overlap for the most part (from 1-99). But, at the same time, they include each other's opposite (Could includes Must, and Not Necessarily includes Cannot). So, they often cover the same ground—the middle ground where things might be true—but at the ends of the spectrum (Must and Cannot), they differ significantly.

Another way to see how they differ is to realize that Not Necessarily True is identical to could Be False. So, comparatively, one term is Could Be True (there exists a possibility something is true, but it doesn't have to be) and the other Could Be False (there exists a possibility something is false, but it doesn't have to be)

It's a subtle yet definite difference, but the good news is that you aren't typically tested directly on the difference. Please let me know if that helps. Thanks!

[mankariousc]

I had a quick follow-up question regarding this discussion. Not Necessarily True includes Must Be False, correct?

[Jonathan Evans]

Hi, mankariousc,

Yes, "not necessarily true" is logically consistent with "must be false cannot be true."

That is, something that "cannot be true" clearly is "not necessarily true."

e.g. If banging my head against the wall cannot be a good way to get rid of a headache, then banging my head against the wall is not necessarily a good way to get rid of a headache.

Pay attention to the following conditional, though:

• Something that cannot be true definitely is not necessarily true.
  
  .....Cannot Be True Not Necessarily True
  
  .....Contrapositive: Must Be True Could Be True
  
  Something that must be true definitely could be true.

Note that this relationship only works one way. It is not the case that *Not Necessarily True Cannot Be True.

Just make sure that you keep these ideas consistent, and you'll be in good shape!

[cmorris32]

Hello!!

I'm still kind of confused on what the right/wrong answers would be for these False to True questions. The resources I have are the PowerScore 2020 edition bibles and I took a PowerScore Live Online course. Can someone tell me if I am correct?

"Which one of the following could be true?"
- This question is asking us to identify an answer choice that could be true
- Because "could be true" can range from 1-100, the 4 incorrect answers CANNOT be true
- Am I correct in saying that if there is an answer choices that MUST be true, that would be the correct answer choice, since "could be true" ranges from 1-100, which includes must be true?

"Which one of the following could be false?" / "Which one of the following statements can be false?"
- This question is asking us to identify an answer choice that is not necessarily true
- Because "not necessarily true" can range from 0-99, the 4 incorrect answers MUST be true
- The correct answer is not necessarily true
- Would there ever be an answer that MUST be false in the list of answer choices? If yes, an answer that MUST be false (cannot be true) would be the correct answer since not necessarily true (0-99) encompasses cannot be true, correct?

"Each of the statements could be false EXCEPT"
- This question is asking us to identify an answer choice that must be true, because "could be false" translates to "not necessarily true," and then with the EXCEPT, we need to use the logical opposite of "not necessarily true," which is "must be true"
- The 4 incorrect answers will be not necessarily true
- The correct answer must be true

"Which one of the following statements must be false?"
- This question is asking us to identify an answer choice that cannot be true
- The 4 incorrect answers could be true or must be true
- The correct answer cannot be true/impossible

Thank you for any corrections/clarifications in advance!
- Caroline

[Dave Killoran]

Hi Caroline,

Yes, you nailed all of those—well done!

Thanks!

[SGD2021]

Hello, I have a question about logic games "could be true" questions in general. For instance, if we aren't able to come up with the full range of solutions via hypotheticals for a problem on test day and we want to use process of elimination of answer choices for Could be True questions, would it be incorrect to go one by one eliminating answers as soon as we find a flaw in them? I know that the four incorrect answers cannot be true (in any situation) and one correct answer COULD be true, which means it doesn't have to be true in all situations. Does that mean that it would be dangerous to eliminate answers as soon as we find a flaw in them since the COULD be true question might accidentally get eliminated that way? Or, is it usually the case that the COULD be true answer on the LSAT doesn't usually have a flaw in it so that is an okay approach to take? Also, how would the same question about eliminating apply to Cannot be True, Must be True, and Not Necessarily True questions?

Thank you!

[Dave Killoran]

would it be incorrect to go one by one eliminating answers as soon as we find a flaw in them?

I'm not following what you mean by a "flaw" in them. A flaw in what way? The incorrect answers simply cannot ever occur, so if that's the "flaw" here then yes, that immediately makes them wrong

Thanks!