Excellent question, Mia. I would say that the short answer is no, adults do not exist anymore. What does that mean? By adult we usually understand someone who knows who he or she is, that is, who has managed to assume a unified, stable, identity that gives him or her a place in the world. In distinction from the child or the adolescent who are considered in search of an identity, depending for who they are on an identity given to them, precisely, by the adult, the adult is the one who is supposed to have achieved an identity. Another word for identity is that of authority (more or less, I don't have the time to be precise here). Having an authority means assuming oneself as the source of one's identity, and thus being also in the position to assign others, who are not in this position (i.e. who are not adults) their identity. The transition from childhood to adulthood is ideally the transition from being subjected to the authority of another as a source of one's identity, to achieving such a relation to oneself when one becomes one's own source of authority. However, due to a process that has been much documented and that has basically been taking place since the rise of modernity (around the mid 16th century) the concept of authority has been slowly eroding and vanishing, that is, the concept of a possibility of a source of identity that will be stable and able to give orientation to other identities has been disappearing. together with this disappearance  the concept of the adult inevitably has to disappear as well, and all we are left with are to an extent the position of the one who is not entitled to an authority, the one who cannot give oneself, nor others, an .identity. in other words, the child. As such, the world we live in, which has also been chracterized as a world undergoing a crisis of legitimacy, does not have place for what used to be understood as an adult. We are all haunted by the position of childhood, incapable of  finding an identity that we accept as legitimate.

Thanks Dave, great response -- very much enjoyed reading it.

As an aside, one remark. I remember at some point reading that "childhood" was essentially a Victorian invention; that before this point (at least in the modern West) children were considered to be a variety of smaller, less capable adults. This suggests that there was only a small window of time in the history of the modern west, say a hundred years or so 1850-1950, when childhood and adulthood actually were able to co-exist -- in which case I guess the "invention" of childhood appears as something completely different, a major reaction/revolution against the idea of "adult" which somehow dismantled that category from within.