Q10 - Unplugging a peripheral component

[john.as.camacho]

I narrowed it down to B and D. What are the ways that I can eliminate D? There is a generalization being used to support the conclusion and it is too broad. I guess that the "too broad" is what's wrong with it but just let me know.

[a.andreoli88]

Conclusion: It must be that Fred's mouse to the computer became unplugged.
Why must this be (according to the passage)?
The passage states its reasoning for its conclusion as follows:
If a mouse is unplugged, then all components requiring the mouse are unusable.
Conditional statement above put into "equation" form:
Sufficent--> Necessary
If unplugged --> then unusable
The conclusion turns this conditional backwards (if unusable, then unplugged), which is a sufficient/necessary flaw.
(B) answers this
(D) is not the answer because this is a necessary/sufficient flaw, not a generalization flaw.
See PT 45, section 1, Q7 for an example of a generalization

[christine.defenbaugh]

Excellent analysis!

This is a classic argument structure. The first premise establish a conditional statement (If [unplugged] --> [unusable]). The second premise establishes that the necessary condition has been fulfilled ([unusable]). From the original conditional, there's nothing that can actually be validly concluded from this.

The argument attempts to conclude that the sufficient condition must have been met. The author is reversing the direction of the conditional in order to conclude this.

There are many ways to describe an error of "reversing the conditional". This is often described as "confusing the necessary condition for the sufficient condition" (or vice versa), but (B) is another way to describe the same error. The argument is treating an event [unplugging the mouse] that CAN cause a certain event [software becomes unusable], as though it is NECESSARY. This is a very classic way to describe necessity/sufficiency confusion. In a conditional If A --> B, A may lead to B, but it may not be the only thing that leads to B.

While (D) may look attractive at first glance, remember that we are not allowed to question premises. If the author relies on a generalization as a premise, we must accept that premise as true in order to properly evaluate the logic. Even if the premise were something like "All boys like sports", we could not attack the argument just because the premise is too broad.

In this case, I'm not sure the generalization even IS too broad - some generalizations are true! (All apples are fruit). How would we even begin to evaluate whether or not the generalization in the premise was too broad? We'd probably have to rely on outside knowledge, and that's not allowed!

Let's take a quick look at the remaining answer choices as well:

(A) This describes the classic error of using a term in two different ways, but the argument does not change the meaning of "unusable" from premise to conclusion.

(C) Introducing unrelated information is not necessarily a logical flaw, unless that's the only support the author uses! The premises in this case are clearly related anyway!

(E) Both the premise and the conclusion are about things that DO require a peripheral component. Things that DON'T are out of scope!

I hope this helps a bit!

[ym737]

I chose the right answer, but I am still a little bit confused. Since it says clearly the word "cause" so is it a causal relation? if it is a causal relation, the rule of conditional relation no longer applies. or should I assume when the cause is the only cause, it is a necessary condition? what's the relationship between causal and conditional?

[christine.defenbaugh]

Thanks for posting, ym737!

You're right to be concerned about the relationship between conditional and causal connections. However, you don't want to think of them as mutually exclusive activities. Let's take a look at a few examples:

A always causes B. While this is a causal relationship, it's also a conditional one! The cause will always produce the effect - it's a guarantee! So, it would be perfectly legitimate to diagram this as A --> B

A is the only possible cause for B. Again, A is the cause, but the conditional relationship has now changed. Since it's the only possible cause, what we really know is that if we see the effect B, we can know for certain that A caused it! So, it would be legitimate to diagram it as B --> A.

A sometimes causes B. Here, we have a causal relationship again, but I have no guarantee that A will definitely cause B. And I also don't have a guarantee that B always gets caused by A. So I can't diagram this! There's no conditional relationship here, even though there is a causal one!

In this question, the premise indicated that the cause will always cause the effect. But we did not establish that the cause is the only possible cause. That's what the conclusion erroneously claims by saying the cause "is necessary".

Please let me know if that helps clear up a few things!!

[roflcoptersoisoi]

Premise: Unplugging a peripheral component such as a mouse causes all of the software that is dependent on said component to become unusable.

Conclusion: A software on Fred's computer has become unusable so it follows that the mouse (a peripheral component) of fred's computer has become unplugged.

Takes for granted that something that guarantees a result is necessary for that result. In other words, something that can cause something to occur is the only thing that can cause it to occur. Perhaps there is another reason for why the software is unusable, perhaps he has a computer virus that has rendered it as such.


(A) No such shift in meaning occurs. Descriptively inaccurate and doesn't describe the flaw.
(B) Bingo
(C) Descriptively inaccurate and doesn't describe why the reasoning is erroneous.
(D) Tempting but there is no faulty extrapolation in this argument. For this answer choice to be a contender, the logic in the premise would have to be reversed. i.e., If a software in one's computer is unusable then it's because the mouse which is required for the software to be usable has been unplugged. Plus how do we know that the ascertain is too broad?
(E) Descriptively accurate but doesn't describe the flaw.