Hi, Alexandra!
Welcome to our forums, and thank you for the question!
Good job picking out some of the characteristics in common to both Strengthen questions and Justify the Conclusion questions. Both question tasks ask you to Help the argument. Answer choices for both questions will help to improve the likelihood that the conclusion is valid.
However, even though words such as "properly drawn" often appear in question stems for Justify the Conclusion questions, certain phrases or expressions do not by themselves guarantee that a question falls into one category rather than the other. Instead, you have to focus on the entire meaning of the question stem to discern for sure what kind of question it is and what you are supposed to do.
For a complete discussion of Justify the Conclusion questions and how they differ from Assumption and Strengthen questions, you may consult Chapter 10 of the Logical Reasoning Bible, but let's discuss briefly the key attributes of Strengthen versus Justify the Conclusion questions:
- Strengthen Questions ask you to find an answer choice that, if true, would do the most to bolster the argument. The credited response will provide the most helpful information to conclusion. However, even if the information in the credited response were true, we do not need to have a perfect argument, just a better one.
Justify the Conclusion questions ask you to find an answer choice that, if true, would guarantee that the conclusion is properly drawn. In this case, the credited response will not only help the conclusion but also will guarantee that the conclusion is valid. For Justify the Conclusion questions we are trying to create a perfect, logically valid argument.
Here is an example of two question stems that share similar wording but ask you to perform different tasks:
- "Which of the following, if true, would be most helpful in establishing the conclusion is properly drawn?" This is a strengthen question.
"Which of the following, if true, would serve to establish that the conclusion is properly drawn?" This is a justify the conclusion question.
Notice that one key distinction between Justify and Strengthen tasks is the question of degree. Strengthen questions look for something
most helpful. Justify questions look for something that along with the premises would serve to establish the conclusion is valid. There is no "more" or "less" helpful on Justify questions. It is simply a question of whether the answer choice does the job or not.
This brings us to question 3 on page 103:
- "Which one of the following, if all of them are true, is LEAST helpful in establishing that the conclusion above is properly drawn?"
Notice the degree word, "LEAST." This word tells us we're looking for something less helpful than the other answer choices. In a Justify the Conclusion situation, as stated, there is no "more" or "less" helpful. A Justify the Conclusion EXCEPT question would be phrased as follows:
- "Which one of the following, if all of them are true, would not serve to establish that the conclusion is properly drawn?"
In this (exceptionally rare) scenario four of the answer choices would serve to establish a valid conclusion and one would not.
I hope this helps! Please follow up with further questions.