When Goodman Brown goes into the forest in "Young Goodman Brown," what does he learn? What does he fail to learn?

I think the
previous contributor has already given a very strong answer to this question. In Brown's time in
the woods, he gains insight into the pervasiveness of human sin. He learns that the people
around him, people who he had assumed were good Christians, were in fact not quite so pure and
righteous as he had previously assumed.

That being said, there are criticisms
one can level about Brown, especially when viewed from within the Christian tradition. One of
the most significant questions is this: why does he place so much trust in the vision to begin
with? After all, to put his faith in that vision ultimately entails putting his faith in the
Devil. From a Christian perspective, this is obviously a deeply problematic thing to
do.

In addition, I would note that, from the very beginning of the story,
Brown is portrayed as possessing a very simplistic, black-and-white view on human nature. He
idolizes his wife, casting her as a paragon of goodnessreferring to her as "a blessed
angel...