PrepTest 159, Section 3, Question 25
Paleontologist: Most biologists accept that birds evolved from(54 more words not shown)
The paleontologist's argument is most(10 more words not shown)
- AIt overlooks the(18 more words not shown)
- BIt fails to(28 more words not shown)
- CIt takes for(23 more words not shown)
- DIt overlooks the(33 more words not shown)
- EIt fails to(31 more words not shown)
Reading the argument
The oldest bird fossils we know about are older than the oldest maniraptor fossils we know about. I can understand why that makes some biologists hesitate. How could birds evolve from animals that appear later in the known record?
There is a possible answer: the record may be incomplete. Maniraptors could have existed earlier, and evidence of those earlier animals might not have been discovered. So the dates of known fossils don't conclusively rule out the proposed ancestry.
But does that make withholding acceptance misguided? Not necessarily. There's a difference between saying a theory has been disproved and saying the evidence hasn't convinced you. The skeptical biologists have not accepted the theory; they haven't claimed to have proved that it is impossible.
Imagine I claim there are unicorns on Mars. You ask for evidence, and I respond that your doubts are misguided because you haven't ruled out undiscovered unicorns. That reply hasn't supplied support for my claim. The possibility that evidence might turn up doesn't make your current uncertainty unreasonable.
What we’re looking for
For the flaw question, that's the problem I'd predict: the paleontologist treats a failure to disprove the theory as a reason to criticize people who aren't yet convinced. The burden of supporting the claim doesn't disappear just because skeptics can't eliminate every possibility.
Working the answers
- A
The paleontologist doesn't conclude that the theory is true simply because one argument against it is flawed. The conclusion is that these biologists' reason for withholding acceptance is misguided. A attacks a stronger claim about the theory's truth that the paleontologist doesn't make.
- B
Earlier maniraptors leaving no surviving older fossils is another possibility consistent with the theory. But the paleontologist's objection already relies on the possibility that the known record is incomplete. This additional possibility doesn't identify why the biologists could reasonably remain unconvinced on the evidence currently available.
- C
No older maniraptor fossils have been presented, and the paleontologist never says finding them would by itself prove that birds descended from maniraptors. Older existence and actual ancestry would be different questions. C attributes a proof of ancestry that the argument doesn't offer.
- D
There could be other evidence against the theory, but we don't need to invent it to identify this flaw. The paleontologist criticizes withholding acceptance based on the known fossil dates. The key question is whether an apparent lack of sufficient evidence can itself justify remaining unconvinced, not whether some separate refutation might exist.
- ECorrect
It can be reasonable to refuse to accept a theory because the evidence discovered so far seems insufficient. The possibility of undiscovered supporting fossils doesn't require the biologists to accept the theory now. E captures the distinction between failing to disprove a claim and having enough reason to believe it.
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