Isn’t libertinism the same thing as promiscuity; being a slut?
Similar, yes. However, many libertines have actively chosen this lifestyle, unlike many promiscuous people who merely drift into such behavior without much conscious thought or choice. The difference in outlook being that, for many people, promiscuity is a manifestation of other issues going on in that person’s life, whereas, for the libertine, it is a matter of philosophy and a way of looking at the world that goes beyond mere sexual expression.
