Personal autonomy is defined as a capacity for self-determination and self-direction. It is a skill which is often possessed by people who are sure of themselves and of the outcome of their actions.
In Pride and Prejudice personal autonomy is explored from a number of viewpoints, but let's emphasize on one: the autonomy of Lydia Bennet. The reason why Lydia makes a good study for personal autonomy is because she is part of a group of sisters who are given quite a lot of autonomy considering their social standing. This is because the Bennet household does not hold a lot of disciplinary values over the daughters. Case in point, when Lady Catherine DeBourgh asks Elizabeth which of her sisters were "out" (in society), she is shocked to find out that ALL of the Bennet sisters are out in society.
Elizabeth explains it in one way:
However, there is a problem with this: Lydia's freedom for personal autonomy has been directed the wrong way. Mrs. Bennet's interest in marrying off her daughters may have translated erroneously in Lydia's mind, who sends all the wrong messages to the males that she likes. Lydia is lose, breaks with every rule of propriety expected of young ladies, calls men by their first names, and is allowed to be seen in their company, without a chaperone. Lydia has acquired quite a reputation, and her mother seems to be her enabler. This is illustrated in the way that Mrs. Bennet allows Lydia, who is her youngest, to stay at Brighton knowing that the place is rife with single soldiers...of whom Lydia is particularly fond!
`[...] I think it would be very hard upon younger sisters, that they should not have their share of society and amusement because the elder may not have the means or inclination to marry early. -- The last born has as good a right to the pleasures of youth, as the first. And to be kept back on such a motive! -- I think it would not be very likely to promote sisterly affection or delicacy of mind.''
In Lydia's imagination, a visit to Brighton comprised every possibility of earthly happiness. She saw, with the creative eye of fancy, the streets of that gay bathing place covered with officers. She saw herself the object of attention to tens and to scores of them at present unknown. She saw all the glories of the camp -- its tents stretched forth in beauteous uniformity of lines, crowded with the young and the gay, and dazzling with scarlet; and, to complete the view, she saw herself seated beneath a tent, tenderly flirting with at least six officers at once.As a result of her fantasies, Lydia elopes with Wickham, who is a good for nothing soldier with a record for demoralizing women. Hence, personal autonomy, in Lydia's case, leads her to a ruin that is quickly mended by the beneficence of Darcy's money, and his love for Lizzie. We know that, regardless, Lydia never really understands to what extent her actions affect everybody else. She simply wants to be a soldier's wife and to live her fantasy-life as she supposes it to be. Her mother ends up approving everything Lydia does, simply because Wickham ends up marrying Lydia (thanks to the interference of Darcy). Regardless, Lydia's actions follow her until the end, and she never changes her ignorant ways.
One way of looking at personal autonomy (and the lack of personal autonomy) in Jane Austen's Pride and Prejudice is to contrast Elizabeth Bennett's freedom and autonomy with the constrained actions of other characters, as does Elizabeth herself in her reflections about marriage:
"She had always felt that Charlotte's opinion of matrimony was not exactly like her own; but she could not have supposed it possible that, when called into action, she would have sacrificed every better feeling to worldly advantage"
One important issue though, is to remember that Jane Austen gives far less unqualified admiration to autonomy than would most of her modern readers. Darcy, for example, is constrained by his upper class upbringing to treat his servants well and maintain his family library, both good things. The restraint and good manners of the older Bennett girls are contrasted with the disastrous lack of restraint of Lydia. In fact, it is when Elizabeth herself acts out of reflection rather than impulse (accepting Darcy, for example) that she behaves best. Austen, here as in Sense and Sensibility, tries to show that the best character is one in which autonomy is regulated by custom, and impulse by education.