PrepTest 132

Incorrect. The conclusion is about sentient beings outside our solar system, so this answer choice in discussing such beings inside our solar system is out of scope.

Incorrect. A desire to communicate doesn't establish that they will communicate. It's possible they'd have the desire but lack the capability, or they'd communicate accidentally despite not having a desire to do so.

Incorrect. The stimulus already establishes this answer is true for beings outside of our solar system, which are the only beings in scope of the conclusion, so this answer doesn't add anything to the argument.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Sufficient Premise

Stimulus Summary:
We can't send ships outside our solar system anytime soon. Aliens would have to be as smart as us to be capable of communicating with us.
Therefore: Aliens exist outside our solar system AND not Intelligent as us → We can't determine they exist anytime soon

Answer Anticipation:
While it's not immediately apparent, this argument starts with the conclusion and then provides the reasons to believe it's the case. We can tell this because the opening statement is about the impossibility of determining aliens exist, and then the premises start ruling out ways that we could make that determination.

With that structure in mind, we can see that this argument follows a common method of reasoning—ruling out alternatives. In this case, however, the conclusion rests on ruling out all possibilities, not on ruling out all but one possibility and concluding it. In short, there are ways of determining aliens exist, and this argument attempts to rule them all out to conclude that we can't determine whether aliens exist.

Even if this argument features a variation on the normal pattern, it still relies on the same logic. And one of the primary potential flaws in an argument that relies on ruling out alternatives is when it fails to establish that the provided list of alternatives is comprehensive. In other words, there may be more ways to determine that these aliens exist than are ruled out by the premises.

So what methods are ruled out? The aliens contacting us is eliminated as a possibility—they'd have to be smarter than us, and the conclusion is conditioned on them not being that intelligent. And us traveling to them via spaceship is ruled out, as that's not going to happen anytime in the near future.

Those are two methods ruled out, but there are presumably other methods by which we could determine their existence—maybe through telescopes or other imaging technology. Whatever the case, the correct answer is going to have to establish that there are no other ways than these two to determine whether these aliens exist.

Answer Explanation:
This conditional answer is set up to establish that there are only two ways of determining whether aliens exist—they communicate with us, or we send a ship. It states that if it's not one, then it must be the other. So if it's neither, then nothing works. Since the conclusion is that nothing works and it's based on ruling out us traveling to them and conditioning the conclusion on them not being smart enough to contact us, this answer justifies that conclusion.

Key Takeaway:
It's easy to start to silo your knowledge of the LSAT—to only think about methods of reasoning in Methods of Reasoning questions, for example. However, bringing these concepts to your work in other questions can be helpful in approaching them. For instance, most of the common flaws and methods of reasoning, when present in other question types, have patterns to the correct answers. Connecting all of these concepts is key to LSAT mastery.

Incorrect. This answer reverses the connection in the last statement, so it's not a sufficient assumption.