PrepTest 126, Section 4, Question 26
Astronomer: I have asserted that our solar system(48 more words not shown)
The reasoning in the astronomer's(6 more words not shown)
- Acriticizes the astronomer's(5 more words not shown)
- Binfers the truth(15 more words not shown)
- Cignores the possibility(8 more words not shown)
- Dpresumes that the(11 more words not shown)
- Efails to precisely(5 more words not shown)
Reading the argument
How much debris was there when the craters formed? The amount in the solar system now might not settle what was available long ago. I'd want more evidence before accepting the astronomer's thesis.
But look at the reason the astronomer actually gives: the opponents haven't proved it false. That's not a reason to declare it true. Imagine saying, “There are unicorns on Pluto. You haven't disproved it, so you must admit I'm right.” The failure to knock down a claim doesn't provide the missing evidence for it.
What we’re looking for
Inconclusive evidence can leave us unsure. The astronomer skips that possibility and treats the absence of a successful disproof as a successful proof. That's the step the flaw answer should identify. We don't need to know the real history of the moon to see that this defense doesn't establish the thesis.
Working the answers
- A
The astronomer criticizes the opponents' evidence as inconclusive. That's different from dismissing them as dishonest, unintelligent, or otherwise untrustworthy. The flaw lies in what the astronomer infers from their failure to prove the thesis false, not in a personal attack on them.
- BCorrect
The argument moves from “They haven't proved me wrong” to “They should admit I'm right.” Those aren't equivalent. The thesis might be true, false, or not yet resolved by the available evidence. Merely calling the opposing evidence inconclusive doesn't establish which possibility is correct.
- C
The thesis rejects a proposed explanation involving meteoroids and other debris. It doesn't rule out every alternative explanation for the cratering. If anything, rejecting that explanation leaves us asking what else happened. The problem is the unsupported rejection, not ignoring all possible alternatives.
- D
The astronomer discusses attempts to disprove the thesis and criticizes their results. That doesn't mean the thesis is being declared off limits to rational criticism. A person can allow criticism and still make the mistaken inference that unsuccessful criticism proves the person's position right.
- E
A more precise definition of meteoroids wouldn't repair the leap from no disproof to proof. We can understand the proposed role of cosmic debris well enough to evaluate that reasoning. The argument's problem remains even if everyone agrees on the technical vocabulary.
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