What is Hawthorne's ultimate message about humans and/or society in The Scarlet Letter? Is Hawthorne more optimistic or pessimistic about...

It is safe to conclude that Hawthorne's ultimate message
about society in The Scarlet Letter is that evil lives in the house
of sinners as much as in the house of those who consider themselves to be free of sin.
However, he also shows us how the resilience of a mind that is free from guilt can
overcome any obstacle- and that is a very positive
message.

We see in the characters of Dimmesdale and the
rest of the clergymen the typical holier than thou attitude of those who hide behind it.
They criticize Hester, threaten to take her child away, isolate her, and refuse to hear
any of her arguments. They basically treat her inhumanely. Her punishment does not seem
to end. Through this perspective, Hawthorne's view of humanity may seem
pessimistic.

Yet, we find Hester to be the epitome of the
female warrior who stands by her independent spirit and defends herself until the end.
She is what makes the story optimistic and she is what keeps us hoping for the best
while seeing the worst: We only tolerate what happens to her because she, herself, can
tolerate it.  We only tolerate Dimmesdale because she does. We even fear Chillingworth
because she fears him also.

Therefore, Hester is the
strongest force that moves the plot of the story. Her strength of character and mind is
quite an optimistic view of humanity: We can overcome whatever is thrown our way. In a
dark and mean world, we can still survive.

That seems to be
the central message about humanity that Hawthorne wants to
convey.