Self-study
Astronomer: Does a recent meteorite from Mars contain fossilized bacteria. █████████ ██████ █ ██████████ ██████ ████ ███ █████████████ ██████████ █████ ██ ███ █████████ ██████ ██ ██████████ █████████ ██ ███ ███████ ████ ████ ███ █████████ ██ █ ███████ ███ ██████ ██ ███ ████████ ███████ █████████ ████████ ███████ ████ ██████ ██ ██████ █████ ████ ███ ██████ ███ █████ ██ ██████████ █████████ ███ ████████ ███ ████████ ████ ███████ ████████ █████ ██████ ██ █████████ ██ █ ███████ ██ █████ ██████ ██████ ████ █████ ██ █████ █████████ ████ ██ █████ ███████
Summarize Argument: Phenomenon-Hypothesis
The astronomer concludes that the structures found in the meteorite could be bacteria, rejecting Tagar’s claim that they’re too small. The author rejects Tagar’s view because two other biologists hold a differing view that could explain the structures’ small size.
Identify and Describe Flaw
The problem with this argument is that the astronomer gives no reason for siding with Swiderski and Terrada instead of Tagar. In order to prove this conclusion, the argument would need to provide support for Swiderski and Terrada’s claim that bacteria would shrink when they’re short on nutrients, but since it doesn’t, the astronomer’s preference for their view is arbitrary. The astronomer overlooks the possibility that Tagar could have the correct position.
14.
Which one of the following ████ ██████████ █████████ █ ████ ██ ███ █████████ ██ ███ ████████████ █████████
a
The argument presumes, ███████ █████████ ██████████████ ████ ███ ███████████ █████ ████ ██████ ████ ███ █████ ██████████ ██ █████
This is both irrelevant and descriptively inaccurate. The argument isn’t concerned with what the astronomers believed in the past; only their current views on this issue are referenced.
b
The argument provides ██ █████████████ ███ ██████ ██████████ ██ ███ █████ ██ ███ ██████ ████ ███ █████ ██ ███ █████████ ████ ██ ████████████
This describes how the astronomer chooses to accept Swiderski and Terrada’s position over Tagar’s without providing any justification for doing so. Just in case you're misunderstanding the grammar of (B) -- the two competing sets of authorities are Tagar (one set) and Swiderski and Terrada (the other set). The author assumes Swiderski and Terrada are correct over Tagar.
c
The argument takes ███ ███████ ████ ███ ██████ ██ ███████████ ██████████ █ ██████████ ██████████ ██ ██ ██████████ ██ ███ ████████ ████ ██████████ ███
The astronomer never appeals to the number of experts who endorse a theory as evidence of its accuracy. We don’t know how many other authorities share either of the views discussed.
d
The argument appeals ██ █████ ████ ██████████ ██████ ████ ███████ ███ ████████
The astronomer only appeals to one view—Swiderski and Terrada’s—and assumes that it disproves Tagar’s. The flaw is failing to explain why it should be preferred over Tagar’s.
e
The argument presumes, ███████ █████████ ██████████████ ████ ███ ████████ ██ ███ ███████ ███ ███████ ██████████
The argument does the opposite of this, assuming that Swiderski and Terrada’s theory disproves Tagar’s. In doing so, it treats one opinion as more justified than another.