Self-study
Biologist: Humans have five fingers because we descended from a fish with five phalanges in its fins. ███████ ███ ██████████ ██ ███ █████████ ███ █████████████ ██ ███████ ██ ██ ████ ██ ████ ██████ ████ ███████ █████ ████████ ███████████████ █████ ███ ███ █████ ███ ██ ██████ ███ █████████ ████ █ ████ ████ ███ █████████ ██ ███ ████ ███ ███ ███ ███████ ██ ████ █████ ████ ██ █████ ██ ████ ██ ███████ ████ ████ ██████████████
Summarize Argument
The biologist concludes that humans would be equally content with having six fingers per hand if we had descended from a fish with six fin phalanges rather than five. This is because a hand configuration with six fingers is no more or less useful than one with five fingers.
Notable Assumptions
The biologist shifts from usefulness (in the premise) to contentment (in the conclusion) without justification. This means that the biologist assumes that usefulness is the only relevant factor to how content we are with our hands.
11.
Which one of the following, ██ █████ ████ ███████████ ███ ███████████ █████████
a
Everyone is equally ███████ ████ ███ ███████ █████████████ ██ ████████
The biologist never claims we actually are content with having five fingers, just that we would be equally content with six fingers. Our current contentment levels are irrelevant to that claim.
b
Humans are never ███████ ███████ ████ ███ ██████ ██ ███████ ███████████
We’re not talking about things that are unequally useful, only things that are equally useful. This doesn't help us compare contentment levels with equally useful hand configurations.
c
Humans are always ███████ ███████ ████ ███ ██████ ██ █████ ███████████
This affirms the biologist's assumption that there's a strong relationship between contentment and usefulness. Hands with five or six fingers are equally useful, so this strengthens the conclusion that we'd be equally content with either.
d
The perceived usefulness ██ ███ █████████████ ██ ███████ ██ ██ ████████ ██████ ██ ███ ███████████
Like (A), this doesn't help us to compare the two different possibilities. This also still doesn't explain how usefulness is relevant to contentment.
e
At least one ███████ ██ ████ ███ ███ █████████ ██ ███ █████
The biologist is posing a hypothetical, so it doesn't actually matter if that hypothetical could ever have been true. This is simply irrelevant.