Hi, Mo_Wan!
Let's do a quick recap of the analysis to be certain we're parsing this stimulus correctly:
- If you support the tax plan, then no chance of election.
- STP CE
Contrapositive: CE STP
- If you get economics, then you don't support the plan.
- TUE STP
Contrapositive: STP TUE
- Conclusion: If you've got a shot at being elected, then you truly understand economics.
- CE TUE
Contrapositive: TUE CE
From the premises, what connections can we make? Not many!
- CE STP
TUE STP
- This means that people who truly understand economics don't support the tax plan. Since these people don't support the tax plan, they have met a necessary condition to have a chance at being elected. In other words, it is possible that people who truly understand economics could have a chance at being elected, but we don't know for sure whether they have a chance at being elected! We know these people who truly understand economics might have a chance or they might not have a chance.
- STP CE
STP TUE
- This means that if someone supports the tax plan, we know two things: (1) this person doesn't truly understand economics and (2) this person has no chance of being elected. Since both conditionals above share a sufficient condition, we could combine them into one conditional: STP CE & TUE
However, notice that there's no way using the above information that we could arrive at the conclusion or its contrapositive. Using the premises, there's no way we could start with "chance of being elected" and end up at "truly understands economics" (CE
TUE) or start with "doesn't understand economics" and end up at "no chance of being elected" (
TUE CE).
Let's see if we can determine where the connection broke down.
- From the conclusion that CE TUE it seems as thought the author is trying to make the following erroneous connection: *CE STP TUE*
This is based on the mistaken reversal *STP TUE*. The premises state TUE STP. The correct idea is that if you truly understand economics, then you don't support the tax plan. The incorrect idea is that *if you don't support the tax plan, then you truly understand economics.* How could we describe this error? How could we say that *STP TUE* is incorrect. The author thinks that not supporting the tax plan is sufficient to know that you truly understand economics. This is a mistaken reversal. The author ignores the possibility that there could be people who do not support the tax plan who do not truly understand economics. This is what's in answer choice (D). This statement in answer choice (D) explains how not supporting the tax plan is not sufficient to establish that you truly understand economics.
The reason why answer choice (E) is wrong is that it does not describe the flaw we have identified in our analysis. Answer choice (E) describes the following flawed assumption: "People who have no chance of being elected must truly understand economics" (
CE TUE)
However, the author never makes this assumption. This connection doesn't come up. So while answer choice (E) describes a mistaken conditional statement, the problem is that it describes a mistake that the author doesn't make. Since we have to identify the flaw in the author's reasoning, and this is not a flaw in the author's reasoning, this cannot be the correct answer.
I hope this helps!