LSAT 123 | Section 2 | Logical Reasoning: Q23

QUESTION TEXT: Philosopher: An action is morally right if it would be…

QUESTION TYPE: Sufficient Assumption

CONCLUSION: Well being unchanged ➞ right

REASONING:

1. Well being up ➞ right
2. Well being down ➞ wrong
3. wrong ➞ well being down

(Note: I wouldn’t draw out all of these upfront on the actual test. To solve the question, you only need the contrapositive of the third statement above.)

ANALYSIS: This is a highly confusing question. It’s important to focus on what we’re trying to prove. We must show that if an action doesn’t change well being, then that action is morally right.

And the only way to prove this is to use the evidence we have. A quick method on sufficient assumption questions is to take the conclusion, split it apart, and then fill in the evidence to get from the first part of the conclusion to the second. Like this:

Conclusion: unchanged                                   right

Now, we have to go from “well-being unchanged” to the next step. What do we have that does this? In the evidence, nothing directly. But, the second statement can fit in here. It has an if and only if, which means the statement runs both ways. One half of that is this: If something is wrong, it will reduce well being.

You can take the contrapositive and say: If something doesn’t reduce well being, then it isn’t wrong.

That fits! If well being is unchanged, then that doesn’t reduce well being. So we get this:

Diagram: unchanged ➞ well being down ➞ wrong                                  right

That’s actually as far as we can get. The first sentence doesn’t help us connect these two statements. On a sufficient assumption our job is to prove the conclusion. We don’t have to use every single statement to do so.

So, at this point, you should check the answers. One answer says “wrong ➞ right” which connects the gap and proves the conclusion.

If and only If

This one is simpler than it seems. It just means the logic goes both ways. If I say “Wow, you have an amazing application! You’ll get into law school if and only if you apply”. What I mean is:

1. Applying is sufficient for getting in ➞ if you apply, you will get in
2. Applying it ALSO necessary for getting in ➞ If you DON’T apply, you WON’T get in.

That’s it. Both sufficient and necessary.

___________

1. The stimulus already told us that “wrong” is a necessary condition for actions which reduce aggregate well being.
    
   On sufficient assumption questions, you’re looking for new information which adds to the argument and proves the conclusion true. This answer isn’t new info, so it can’t be right.
2. If this had said “an action must be either right or wrong”, it would have been right.
    
   This answer instead says “if something is wrong, it’s not right”. That’s no good. We’re looking for something that says “if something is not wrong, it is right”.
3. CORRECT. In the reasoning, we saw well being down ➞ wrong. Something which leaves things unchanged isn’t down, and therefore isn’t wrong. This answer says that because that action isn’t wrong, it is therefore right.
4. This tells us that actions which leave well being unchanged exist. That doesn’t matter. The stimulus was about what happens if they exist.
    
   (E.g. if I say “you’ll be wealthy if you win the lottery”, my statement is true whether or not you actually win the lottery.)
5. This introduces a new term not mentioned in the argument. That can’t help connect anything. (“Consequences” is much broader than affecting the well being of people.)