#1 - Jim's teacher asked him to determine whether a sample

[Administrator]

Complete Question Explanation

Weaken—CE. The correct answer choice is (D)

Jim’s job was to figure out whether a sample of a substance contained iron. One way to test for iron is to use a magnet, which attracts iron. Given that the substance did become attached to the magnet, Jim concluded that the substance contained iron.

• Premise: Magnets attract iron.
  
  Premise: A given substance is attracted to magnets.
  
  Conclusion: The substance contains iron.

The relationship between the premises and the conclusion is causal in nature and can be represented as follows:

• Cause Effect
  
  Iron Attracted to magnets

Clearly, the assumption underlying this causal relationship is not warranted: just because something was attracted to a magnet does not automatically establish that it contains iron, as there is no evidence to suggest that all substances attracted to magnets have iron. In other words, Jim fails to consider the possibility that magnets might attract substances other than iron, i.e. that there might be other causes for the observed effect. This prephrase immediately shows that answer choice (D) is correct.

Answer choice (A): Whether iron sometimes fails to be attracted to magnets is irrelevant, given that the substance in question did become attached to the magnet.

Answer choice (B): The fact that iron can be attracted to other objects besides magnets has no bearing on Jim’s conclusion, because he chose to use magnets, and knew that magnets do attract iron.

Answer choice (C): Even if magnets need to be oriented in a certain way in order to attract iron, Jim must have know that: after all, the substance in his experiment was successfully attracted to the magnet.

Answer choice (D): This is the correct answer choice. If magnets can attract substances other than iron, this would show that there could be an alternate cause for the magnetic attraction Jim observed in his experiment.

Answer choice (E): The fact that some magnets attract iron more strongly than others has no bearing on the argument in question.

[blade21cn]

I don't understand why the relationship established in the stimulus is a causal one. If the cause is "iron," what does it mean that its effect is "attracted to magnets"? Wouldn't the effect be something else? In other words, the cause and effect here are talking about the same thing. Rather, I tend to think the premise is a conditional statement: Iron → Attracts magnets/attracted to magnets, and the flaw is a mistaken reversal. Specifically, the conclusion drawn mistakes the premise for: Attracts magnets/attracted to magnets → Iron. Any thoughts? Thanks!

[KelseyWoods]

Hi blade21cn!

I think you could also look at this involving conditional reasoning in the way that you describe. Typically, we want to be careful not to confuse causal and conditional reasoning but sometimes there is overlap. In this case, I think you could interpret the argument either way and still arrive at the correct answer choice. If it's easier for you to think of this argument in terms of conditional reasoning, go for it!

Best,
Kelsey