Why does “sophomore” refer to a second-year student?

Question

I came across Etymonline's explanation for the word sophomore. I do not understand why this has come to be applied to second-years. Why is a second-year guy a wise one and a fool?

Answer 1

Here are two good columns that address this question rather nicely:

• Word of the Day: Sophomore
• Straight Dope: Sophomore

EDIT: At Hugo's insistance, I'll at least give a tease:

Though the first part does come from the Greek word sophos ("wise"), there is no direct relation to the Greek word for "foolish" as is commonly believed. In truth, sophomore is a variation of sophist, a word that has a long and twisted history in itself.

and:

In Ancient Greece, the Sophists were initially a class of professional teachers who gave instruction in various fields. The word eventually took on a derogatory sense and was applied to someone of this class who, while professing to teach skill in reasoning, was more concerned with ingenuity than with soundness of argument.