A book such as Moll Flanders would never exist without the ideas of The Enlightenment in which every person has worth. Moll is the at the bottom level of everything; she is a woman in a man's world, and a poor, immoral woman at that. People who do not benefit from her immorality look upon her as a whore, but fail to recognize that she can do none other than sell and exploit her femininity to live.
She reflects upon everything from the bottom, looking up to the hierarchies of English society. Moll is able to make broad sweeping judgements and criticisms of life based on her experiences and observations. She tells the book in a way that I feel is meant to inform and caution the reader about the evils of life. She repeatedly observes that "...men choose mistresses by the guise of their affection." (pg 83) and is wounded and mystified at the lack of love in marriages: "...marriages here were the consequences of politic schemes for forming interests, and carrying on business, and that love had no share, or but very little, in the matter." (pg 83.) Although she despises both of these themes she is on the course and eventually does "sell out" and take part in both the aforementioned evils.
Moll's hypocracy and helplessness in the face of fate is what gives her dimension. She knows what evil is and understand sit far better than any other female protagonist I have ever been acquainted with has. She continues to create standards and break them by being "evil". This is the only way she can live. To get out of one evil, she must commit another. She is the most extraordinary worst-case scenario and her character wouldn't exist without The Enlightenment making it acceptable to learn and see into such a low and "evil" woman as a part of that society.
I believe that Moll is not evil, but rather that her circumstances warrant her actions and the period in which she lives compels her to do the things she does. It would be an interesting situation to see if Moll had the same flaws and shortcomings if she had been born into better circumstances. I believe so.