Assumption Question Vs Justify the conclusion

[yugal_kishore]

Hi

Per the definitions of different question types in the book, one of them is :

Justify the Conclusion: Justify the Conclusion questions ask you to supply a piece of information that, when added to the premises, proves the conclusion. Question stem example: “Which one of the following, if assumed, allows the conclusion above to be properly drawn?”

How is this different from the Assumption question that expects the test taker to find an assumption?

Secondly, what is exactly meant by '"supply a piece of information" ? Is that piece of information supposed to be the 'unstated assumption' as the example above suggests or can it be an additional premise too? I am not clear with the difference between the aforementioned question types.

Regards
Yugal

[Dave Killoran]

Hi Yugal,

Thanks for the question! One of the nice features of the book is that I preview ideas early on that I later cover in-depth. The overview of question types you see here is just one example, and that discussion is a very brief overview. LAter chapters will cover each type in detail.

Looking at those two types specifically, Justify questions (also known as Sufficient Assumptions) and Assumption questions (sometimes called Necessary Assumptions) are both major concepts that each have their own dedicated chapter (Justify in Ch10, Assumptions in Ch11) So, much more will be coming down the line on these two types, and one of the reason they appear later in the book is that first you need to learn about conditional reasoning in Chapter 6 (which is what covers the "Sufficient" and "Necessary" ideas referenced in these questions). In the meantime, for a description of how Justify and Assumption works, please refer to Chapter 9, pages 298-299 (2017 edition), which first describes each question type abstractly, and then uses as golf example to make the ideas clearer.

Just so the approach makes sense, at the point you are in the book what I'm trying to do is simply give you a preview of the general picture; you are not expected at this point to have 100% perfect understanding of each type! But, the mere exposure to those ideas will start you thinking about how things work, and better prepare you for when these ideas begin appearing in depth. I've found that this approach tends to be most effective and helps students learn faster when they reach the detailed discussion of each idea.

At the same time, I still want to make sure that your questions are answered now so you don't have unanswered questions. The pages cited above will help answer your first question, and in answer to your second question, the "piece of information" that is added is basically an additional premise which is given in the form of an answer choice. An assumption is simply an unstated premise, so what happens in those questions is that the correct answer choice adds a piece of info which, when it is added to the existing premises in the argument, then forces the conclusion to occur. You don't have to guess as to what the additional piece of info is (it's right there in the answer), and there is a killer technique (The Mechanistic Approach) we will talk about in Chapter 10 that allows you to solve these questions more quickly and easily.

So, to help make this clearer, the first thing I'd suggest is that you look at the beginning of Chapter 9 and read about the differences between these question types. If that does not make sense, please post back here and I'll attempt to help clarify it further. But, as you read, be aware that some of the ideas in referenced in Chapter 9 require an understanding of concepts from Chapter 6, so it might not be crystal clear. In time these things will make sense, and I have very carefully constructed the book so that the ideas build on each other (I also have built in previews and foreshadowing, too; if you run across something that isn't clear, in almost every case it will appear again later and be covered in more detail).

Please let me know if that helps. Thanks!

[yugal_kishore]

Hi Dave

Firstly, I must say that your book is really well constructed and presented, and I enjoy going through the nuances and the depth of the subject .

At a high level I have understood the differences, after I referred the first few pages of both - the chapters on Justify and Assumption questions.( I have the 2016 edition).

Thank you for your explanation, as it ensured that I don't have any pending questions at the back of my mind.

Regards
Yugal

[lsatreasoning]

Bro just answer the question.

[Adam Tyson]

Okay, try this:

Justify the Conclusion proves the conclusion of the argument, with no room for doubt. It's a super-strengthen, so it's typically very strong.

Necessary assumption is something the author has to believe. It can be very weak, so it's more like a Must Be True answer. It doesn't have to prove anything; it has to be proven.

And sometimes, one answer is both things. You need it, and it proves the conclusion. But often, you don't need the thing that proves the conclusion, and the thing that proves it doesn't absolutely have to be true.