Assumption Questions Forum

[bigdatta]

Guys I consistently miss at least 1 or 2 of these per test.

What strategy do you use on all these questions?

[tomwatts]

Worth knowing whether they're Necessary ("Which of the following assumptions is required by the argument?") or Sufficient ("Which of the following, if assumed, would allow the conclusion to be properly drawn?"). You should do them a little differently.

[bigdatta]

Tom good point. I suppose I might be confusing the two, either way, I seem to miss both.

Care to elaborate on your strategy for each?

[TheLuckyOne]

Tom good point. I suppose I might be confusing the two, either way, I seem to miss both.

Care to elaborate on your strategy for each?

If asked for "required" it could be anything from something that was not taken into consideration to something that just defends the conclusion, if for "properly drawn" it should be something that completely fills in the gap.

I don't have a strategy I can share, though

[tomwatts]

To check if an assumption is one that the argument really depends or relies on, think of what the argument would sound like if the assumption weren't true. This is variously called the "Negation Test" or other such things.

To check if an argument is sufficient, well, normally it should connect two things that showed up but were not connected in the original argument. Diagramming or looking for language shifts may help. You should be able to make a logically valid argument with what you were given and the correct answer.

[jpSartre]

I'll just reiterate the above with one addition

When the question asks "which of the following, if assumed, allow the conclusion to be logically drawn" it's a justify question; you're not looking for the assumption the author made, rather the assumption he would have to make to be logical

When asked "which of the followed does the author assume" it's an assumption question. There are two kinds of assumptions.

The first kind is similar to the justify question, in that you need to identify the statement that the author assumes. The second kind protects the argument against objections by ruling out something that would interfere with the conclusion.

E.g. if the author says: if something is heavy and red then it is a book, this object is heavy, therefore it is a book, what does he assume?

(H & R) -> B
H
---------
B

He assumes that that object is also red. That would be the answer choice for the first type of assumption question.


The second type of assumption question would go:

All books are heavy. This object is not a book, therefore it is not heavy

B -> (H)
-B
------
-H

The assumption here is that there are no things other than books that are heavy

The first makes a connection, the second rules out any other possible connections.

When you're faced with two answer choices you can't decide between, if you negate them the correct answer choice will weaken the argument. In the example, if you negate the assumption that the object is red into: the object is not red, then the conclusion that the object is a book is weakened because a sufficient condition is not satisfied.

Technical side note: the negating a conditional A->B is A-> not B (technically, not necessarily B, but this will work)

Hopefully helpful Someone might want to clarify the second assumption type though