As far as we know, Earth is the only planet on which life has evolved,

Question

As far as we know, Earth is the only planet on which life has evolved, and all known life forms are carbon-based. Therefore, although there might exist noncarbon-based life on planets very unlike Earth, our scientific estimates of the probability of extraterrestrial life should be generated from estimates of the number of planets like Earth and the likelihood of carbon-based life on those planets.
Which one of the following general principles most strongly supports the recommendation?

Which one of the following general principles most strongly supports the recommendation?

(A) There is no good reason to think that unobserved phenomena closely resemble those that have been observed.

(B) A scientific theory that explains a broad range of phenomena is preferable to a competing theory that explains only some of those phenomena.

(C) It is preferable for scientists to restrict their studies to phenomena that are observable and forego making estimates about unobservable things.

(D) A scientific theory that explains observed phenomena on the basis of a few principles that are independent of each other is preferable to a theory that explains those same phenomena on the basis of many independent principles.

(E) Estimations of probability that are more closely tied to what is known are preferable to those that are less closely tied to what is known.

daagh · Answer

The only reason I select E is for the reason that the prompt and the E talk of estimations of the probabality rather than as all other chocies talk of different other things. things

deborit · Answer

Why option A is wrong? I could understand A and E both are the options hard to eliminate but couldn't understand how the A option is eliminated

Posted from my mobile device

azulonx · Answer

Question is: Which one of the following general principles most strongly supports  the recommendation ?

Recommendation is: "our scientists probability of extraterrestrial life should be generated from estimates of the number of planets like Earth and the likelihood of carbon-based life on those planets"
AKA: Scientist's probability of (E) should be generated from A and B, known estimations.

Why? " As far as we know , Earth is the only planet on which life has evolved, and all known life forms are carbon-based."
AKA: A and B quantities are known to exist with 100% certainty. C and D might exist, but we don't know for sure so it's 0% certainty.

The option the supports the most the recommendation will more closely support the WHY.

(A) There is no good reason to think that unobserved phenomena closely resemble those that have been observed.

C D which we cant observed aren't similar to A and B, which we can observe, therefore probability of E should be done with A and B. 
This is wrong because it doesn't matter if C an D are similar to A and B; they're not including in P(E) because we don't know if C and D exist.

(B) A scientific theory that explains a broad range of phenomena is preferable to a competing theory that explains only some of those phenomena.

Irrelevant. Author is not proposing adherence to scientific theory to support his claim. We might assume that because he recommends to scientist that this will support this claim, but that is a trap.

(C) It is preferable for scientists to restrict their studies to phenomena that are observable and forego making estimates about unobservable things. 
Scientist's probability of (E) should be generated from A and B, known estimations,....because it is better that scientist restrict their studies to phenomenas that are observable.... 
This is the tricky one because it has the word restric and scientist, which one could inferred are related to passage. However, this option doesn't given a direct reason to follow the recomendation. Instead it's appealing at what studies should limit themselves to. Also, like Option A, it talks about observable/unobservable things, which doesn't have the same level of certainty as "known" and therefore doesn't offer a strong reason why P(E) should come from known things.

(D) A scientific theory that explains observed phenomena on the basis of a few principles that are independent of each other is preferable to a theory that explains those same phenomena on the basis of many independent principles.

Irrelevant. Author is not proposing adherence to scientific theory to support his claim. We might assume that because he recommends to scientist that this will support this claim, but that is a trap.

(E) Estimations of probability that are more closely tied to what is known are preferable to those that are less closely tied to what is known.

Scientist's probability of (E) should be generated from A and B, known estimations, because...... Scientist's probability of (E) generated from A and B are preferable to the ones that arent. 
This is the principle that directly supports the recommendation, and even says that the farther away the estimation is from "what-is-known" (100% certainty), the less preferable the estimation is.

gotitright · Answer

Conclusion: Even though non carbon based life, planets unlike earth may be present. But our ‘scientific estimations’ should be based on like earth, carbon based. 
 Reason: what is known is earth & carbon based life. Essentially it’s saying probability should be based on what is known. So our principle should be something like we should take probability from what is known.

A- no this is talking about resemblance b/w known and unknown. And we want something that talks about prob & known.

B- Firstly, this is talking about broad vs some. Secondly, its talking about scientific theory not probability.

C- this is saying we should stop studying & making estimated about unobservable phenomenon. But our principle should be something like what a general probability about something should be based on.

D- Firstly, this talks about independent vs dependant phenomenon. We’re talking about known vs unknown phenomenon. Secondly, this is about scientific theory.

E- Exactly what we said.

agrasan · Answer

As far as we know, Earth is the only planet on which life has evolved, and all known life forms are carbon-based. Therefore, although there might exist noncarbon-based life on planets very unlike Earth, our scientific estimates of the probability of extraterrestrial life should be generated from estimates of the number of planets like Earth and the likelihood of carbon-based life on those planets.
Which one of the following general principles most strongly supports the recommendation?

Hi experts  KarishmaB   MartyMurray   DmitryFarber , can you please confirm if my reasoning is correct to arrive at (E). Would be helpful to know if I faltered somewhere.

(A) There is no good reason to think that unobserved phenomena closely resemble those that have been observed.
 Incorrect , goes against the argument, the author wants to observed phenomena to estimate something about unobserved phenomena. This option doesn't help us in any way.

(B) A scientific theory that explains a broad range of phenomena is preferable to a competing theory that explains only some of those phenomena.
 Incorrect , there is no discussion on number of phenomenons in the argument so "broad range" and "some" phenomena don't make sense here.

(C) It is preferable for scientists to restrict their studies to phenomena that are observable and forego making estimates about unobservable things.
 Incorrect , goes against the argument, the author wants to observed phenomena to estimate something about unobserved phenomena. This option doesn't help us in any way.

(D) A scientific theory that explains observed phenomena on the basis of a few principles that are independent of each other is preferable to a theory that explains those same phenomena on the basis of many independent principles.
 Incorrect , the author is not making any comparison between an observed phenomena derived from  some  principles vs. an observed phenomena derived from  many  principles. It simply wants to draw something about an unobserved phenomena (non-carbon life) using the observed phenomena (carbon life). This option doesn't help us in any way.

(E) Estimations of probability that are more closely tied to what is known are preferable to those that are less closely tied to what is known.
 Correct , spot on, the author wants to estimate non-carbon life on planets using data of carbon-life which is known, this option aligns with the argument.

DmitryFarber · Answer

That looks good to me. Just watch the phrasing shift in C: it's no longer just about what has or has not been observed. It's about whether things are observable or not. We know that carbon-based life is observable because we've seen it here. But we don't know that other forms of life would be unobservable, so C isn't really relevant to the argument.

As far as we know, Earth is the only planet on which life has evolved,

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

As far as we know, Earth is the only planet on which life has evolved,

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards