Self-study
In an experiment, biologists repeatedly shone a bright light into a tank containing a sea snail and simultaneously shook the tank. ███ █████ ██████████ █████████ ██ ███████ ███ ████████ ███████ █ ███████ ████████ ██ ███ ██████ ██ █████ ███████████ █████ ███████ ███████████ ██ ████ ██████████ ███ █████ ██████ ███ ██████ ████████ ███ ██████████ █████ ███ █████ ████ ███ █████ ████ ████ ███ ████ ███ ███ ██████████████ ███████ ██████████ ███ █████ ████ ████ ███████ ██ █████████ ███ ███████ ██ ███ ██████ █████ ████ ███ ███████ ██ ███ █████
Summary
The author gives a causal argument: The snail tensed its foot in reaction to the light alone, and the cause is that the snail has been conditioned to associate the light with shaking.
Notable Assumptions
In causal arguments, we should always be wary of alternative cause. This is the biggest assumption in this argument: perhaps something else is causing the snail to tense its foot other than associating light with turbulence.
7.
Which one of the following ██ ██ ██████████ ████████ ██ ███ █████████
a
All sea snails █████ ██ █████ ██████████ ██ ███ ████ ███ ██ ███ ███ █████ ██ ███ ██████████ ████
The argument’s conclusion is about one particular snail, and the support is limited to that same snail. (A) is not necessary.
b
Sea snails are ███ ██████████ ███████ ██ ██████ ██████ ████ ██ ███ ███ ████ ██ ███ ███████████ ███████████
If this is negated, it doesn’t wreck the argument. The snail could have had prior exposure to bright lights or not, it doesn’t matter.
c
The sea snail ████ ██ ███ ██████████ ███ ███ ██████ █████████████ ████ █████ ███████ ██ ███ ███████ ██ ███ ████████ ██ ████████ ████████
Like (A), we do not need information about the snail population in general. The argument’s conclusion is about one particular snail, and the support is limited to that same snail.
d
The appearance of █ ██████ █████ █████ █████ ██████████ ███ ██████ ██ ███ ███ ███████ ███████ ███ ███████
If negated, (D) is alternative cause, as predicted: it isn’t that the light makes the snail expect turbulence and it tenses because it expects shaking, it’s that the light alone is enough to make the snail tense.
e
Tensing of the ████████ ██████ ██ ███ ██████ ██ ██ ███████████ ██████ ████ █ ███████ ████████ ██ █████ ███████████
Irrelevant. The response could be instinctual or learned response, and it doesn’t affect the argument either way.