The first of these is based on a cladogenic model, where one species gives rise to two species, and the species complex is an artifact of having caught the genome in the act of cladogenesis. This model is used as the major explanation of species complexes, usually along the line of reasoning that if species boundaries are messy it must be a young taxon, usually with the caveat that therefor it is of little importance. This line of reasoning is one of the psychological defense mechanisms used to avoid confronting chaos. Early stage divergence is a good model, but it gets invoked all to often without empirical justification.