How do ideals determine the decisions of the characters in Pride and Prejudice by Jane Austen?

Most of the characters in Pride and
Prejudice have a perspective of what a person's ideal
character, meaning main traits of a person's nature, should be like. This
is especially true of our hero and heroine, Elizabeth and
Darcy. Both know and understand that there are
ideal character traits and not so ideal character traits,
and both feel ashamed when they learn that they have not been acting in line with their
own ideals. Hence, both Elizabeth's and Darcy's ideals
shape their decisions to change their
behavior.

For
Elizabeth, part of what makes up an ideal
character is the ability to accurately judge
others. We see Elizabeth criticizing her sister Jane for Jane's inability to see
anyone's faults. As Elizabeth phrases it, "All the world are good and agreeable in your
eyes. I never heard you speak ill of a human being in my life," and Jane concedes that
she "would wish not to be hasty in censuring any one" (Ch. 4). However, Elizabeth is
right in thinking that the disadvantage of Jane's perspective is that Jane is incapable
of judging people's actions correctly, which can lead a person to make bad decisions,
such as deciding not to expose Wickham in case he is trying to re-establish his
character. Hence, Elizabeth values her own abilities to judge and
discern, thinking that they are far better than her sister's. Yet,
Elizabeth soon discovers that her abilities to discern are really not what she thought
they were, despite the fact that she considers the ability to discern an
ideal character trait. In reality, she misjudges Wickham to be the best
man she's met simply because he is friendly and conversational and misjudges Darcy to be
a despicable person simply because he is reserved and was spoken ill of by Wickham.
Elizabeth, seeing how she has fallen short of her ideal, soon amends both
her opinions and her
actions.

Darcy
also believes in ideal character traits. He values having
pride in one's ethical conduct and "superiority of mind" (Ch. 11). As he
tells Elizabeth later on in the book, he also values good
principles. One of the principles he holds is that he must always speak
the absolute truth, which is one reason why Darcy talks about how inferior he believes
Elizabeth and her family are to himself and how marrying her would be a "degradation" of
his pride during his first proposal. Also, since he believes he has upheld his
principles, he is absolutely shocked when Elizabeth calls him arrogant, conceited,
selfish, and accuses him of not behaving in a "gentleman-like manner" (Ch. 34). In
addition, he believes that his ideal character trait is to uphold his
principles; therefore, he is absolutely ashamed and mortified by
Elizabeth's chastisement and, later, by the things he said to her during his proposal.
Later, Darcy makes an effort to act with less pride and less conceit. Therefore, even
Darcy's ideals make him change his
behavior.