June 1991 LSAT
Section 4
Question 24
Although all contemporary advertising tries to persuade, only a small portion of contemporary advertising can be cons...
Reply
Ravi on February 26, 2019
@LH44,Happy to help.
The stimulus can be diagrammed as
1) Contemporary Advertising - >Persuasion
2) Contemporary Advertising-some-Morally Reprehensible
3) Persuasion-some-Morally Reprehensible
The basic structure of the argument in the stimulus is to combine a
conditional statement with a quantifier (some) to arrive at the
conclusion. This is a valid argument, and we're looking for the answer
that most closely parallels this form.
You said you thought both (C) and (E) were correct. Let's take a look.
(C) says, "A good manager always makes important decisions on the
basis of adequate data, although of course some managers fail to do
this. It follows that some managers are not good managers."
In diagramming (C), we have
1) Good Manager - >Adequate Data
2) Manager-some-Not Adequate Data
3) Manager-some-Not Good Manager
Like the stimulus, this argument is also valid. However, unlike the
stimulus, this argument is using the contrapositive of its first
premise in order to arrive at its conclusion. The argument we analyzed
in the stimulus does not use a contrapositive, let alone one from its
first premise, so the reasoning is different. From this, we can get
rid of (C).
(E) says, "Some short poems are thematically pluralistic, since some
sonnets are characterized by such pluralism, and all sonnets are short
poems."
The first statement in (E) is actually its conclusion. Diagramming (E) we have
Sonnets - >Short Poems
Sonnets-some-Thematically Pluralistic
Short Poems-some-Thematically Pluralistic
In combining the third statement of (E) with its second statement, we
arrive at the conclusion that some short poems are thematically
pluralistic. Just as we saw in the stimulus, the basic structure of
this argument is to combine a conditional statement with a quantifier
(some) to arrive at the conclusion. Like the stimulus, this argument
is also valid. This argument has the same kind of combination that we
found in the stimulus, so it's the correct answer choice.
Does this make sense? Do you see why (E) is correct and (C) is
incorrect? Let us know if you have any more questions!