Hi Jatt,
Thanks for the question. First, take a look at Lessons Four and Five, and the homework for each. That's where these question types first come up.
Since you are good with handling each question type once you know what it is, to help identify each let's start by considering the underlying intent of each, and the words often associated with each. I'll make this pretty casual, so ask for clarification if something doesn't make sense.
Strengthen
Strengthen is the broadest of the three types, and technically both Justify and Assumption questions are specific, narrower forms of Strengthen questions.
The typical words you see in the question stem are "strengthen" (no surprise there), and "support," and "most" (I mean "most" when it is appended to either "strengthen" or "support," or the word "justify"--I'll come back to this point down below).
The typical Strengthen question stem looks like the following:
- Which one of the following, if true, most strengthens the argument?
Which one of the following, if true, provides the most support for the conclusion?
Justify
A Justify question is a super-Strengthen question, where your goal isn't just to help the argument, but to force the conclusion to follow. I think of it as a 100% Strengthen question, which is a pretty high bar to reach.
The typical words you see in the question stem vary, but include words like "justify" and, confusingly, "assumption." But one key word to watch for is "if." When you see that word along with "assumption," you won't be looking at an Assumption question but a Justify question. That's because you are adding something to force a result.
The typical Justify question stem looks like the following:
- The conclusion follows logically if which one of the following is assumed?
Which one of the following, if assumed, enables the conclusion to be properly drawn?
Note the "if" in both of these--that means you are adding a sufficient condition, which references the overall conditional framework that underscores these questions.
But, the following aren't Justify questions, but are instead a Strengthen questions:
- Which one of the following, if valid, most helps to justify the reasoning above?
Which one of the following, if assumed, does most to justify the argument’s conclusion?
Why? Because the
most in each means that 100% soundness isn't required, and since a Justify question is 100%, these don't qualify and are instead Strengthen questions.
Assumption
Assumption questions are a bit different from the first two. In these instances, you are identifying a premise of the argument, but one that the author left unstated.
The typical words you see in the question stem vary, but include words like "assuming" or "assumption," as well as "depends" or "relies, or "required." If you see "if," you probably aren't looking at an Assumption question, but a Justify question (this goes back to the conditional framework underlying Assumption and Justify questions).
The typical Assumption question stem looks like the following:
- The argument relies on assuming which one of the following?
The argument requires the assumption that
That's a start, but certainly do not hesitate to let me know if you have any followup questions. Thanks!