Certain minor peculiarities of language are used unconsciously by poet

Explanation

According to the passage, personal linguistic idiosyncrasies can be used to identify a poet’s work. So if a poem of unknown authorship shares personal quirks with other poems whose author is known, then all the poems must have the same author; thus, we can identify the author of the previously anonymous poem. Why isn’t this test conclusive? Consider (C): It’s always possible that the peculiarity isn’t unique to one author. Perhaps it was an error to identify the peculiarity as a personal idiosyncrasy; perhaps the previously unknown author had the same peculiarity. We wouldn’t have known this, because the author was unknown. Thus it’s possible that any supposedly unique peculiarity is shared by other, unknown authors, and no linguistic peculiarities by themselves can conclusively prove the authorship of a poem.

(A) says that the approach would only be used in certain circumstances, but doesn’t point to any reason why the approach, when used, is inconclusive.

(B) may be true, but the passage never claimed the technique can be used to identify the author of every poem discovered, only that it works in cases where the peculiarity actually appears in a poem of unknown authorship.

(D) The “literary effect” that a poem has is beyond the scope; we’re only interested in identification.

(E) It doesn’t matter whether or not the usages were conscious; the issue is whether the usages are unique to certain authors.

When a concept is defined in a Critical Reasoning stimulus, pay attention! The precise definition is sure to be important for answering the question. Above, the kernel of the problem is the open-ended definition of “personal idiosyncrasy” (it only shows up in the work of one author). When you concentrate on that, the problem introduced by a new anonymous poem becomes more obvious.

Answer: C