- Wed Jul 16, 2025 12:18 pm
#113608
Hi kristina,
You asked:
"Can we always link the necessary condition in the premise and the necessary condition in the conclusion?"
Your question suggests that you may be misunderstanding how Justify questions work, especially those involving conditional reasoning.
Before we get into conditional reasoning with Justify questions, let's start with a (hopefully) straightforward example of conditional reasoning in a Must Be True question.
Imagine that the stimulus states:
1. If A, then B (diagrammed A ->B)
2. If B, then C (diagrammed B-> C)
The question then asks what Must Be True (i.e. what is the inference that we can make).
We can link these two conditional statements to form a chain, A -> B -> C
We can then drop the middle term B to infer: if A, then C (diagrammed A -> C)
And we would be looking for that answer, or its contrapositive (Not C -> Not A)
With Justify questions, rather than finding an inference that we can draw from the facts, we are going in the other direction and instead looking for the missing premise that would prove the conclusion to be true when added into the argument.
So if the argument states:
Premise: If A, then B (diagrammed A ->B)
Conclusion: If A, then C (diagrammed A -> C)
Then you need to figure out the missing piece of the argument that would prove the conclusion. Since we already have A -> B, the missing piece is B-> C because that would prove our conclusion just like in the Must Be True example above.
The argument in this question follows the exact pattern shown above. One thing that makes the argument tricky is the specific wording of the terms used. Another thing that makes Answer E tricky is that it is in the form of the contrapositive, but you should be prepared for that possibility.
So to answer your earlier question, it is not a question of whether we can always connect the necessary terms. Instead, what you are looking for is: which answer, if it were true and added to the argument, would 100% get you from the premises to the conclusion. In other words, what is the missing conditional statement that needs to be added to your diagram to get you to the conclusion? In some cases, it will be linking the necessary terms. In other cases, it will not. It all depends on what they give you in the premises and how those premises relate to the conclusion.
For example, if the argument had given you:
If B, then C (diagrammed B ->C) as the premise rather than:
If A, then B (diagrammed A ->B)
Then the answer would have been:
If A, then B (diagrammed A ->B)
because now that is the missing piece of the argument.
You should be diagramming each of the conditional premises and the conclusion and look at your diagram to try to figure out what is missing. If needed, you could diagram out each conditional answer and add each one to your diagram (one by one) to figure out which one is the missing piece. Of course, that could be quite time consuming, and with practice, you hopefully will be able to narrow down the answers without having to test each one individually. Ideally, you could prephrase the missing conditional statement before looking at the answers and then simply find the answer that matches your prephrase.
Let's look at one more example.
Imagine you have an argument with four terms, A, B, C, and D.
The conclusion states: If A, then D (diagrammed A -> D)
What you need to do to prove this conclusion is to form a chain from A to D in the premises: if A, then B, then C, then D (diagrammed A -> B -> C -> D)
If it is a Justify question, then one of those links will be missing from the argument and that will be the answer. Perhaps it is the first part (if A, then B) that is missing, perhaps it is the second part (if B, then C), or the third part (if C, then D). It just depends on what premises were included and what part is missing.