Competing motivations models and diachrony: What evidence for what motivations?

Competing motivation models are usually established on synchronic grounds. The paper discusses several diachronic processes that give rise to patterns that have been accounted for in terms of competing motivations, such as the development of different alignment systems and that of overt, as opposed to zero marking for number. These processes challenge the relevant competing motivations models both in the sense that they provide no evidence for the principles postulated in these models, and in the sense that they do not point to a competition between different principles pertaining to the encoding of the same grammatical domain.