 In addition, unidirectionality refers to a general developmental orientation which all (or the large majority) of the cases of grammaticalization have in common, and which can be paraphrased in abstract, general terms, independent of any specific case.The idea of unidirectionality is an important one when trying to predict language change through grammaticalization (and for making the claim that grammaticalization can be predicted).Lessau notes that "unidirectionality in itself is a predictive assertion in that it selects the general type of possible development (it predicts the direction of any given incipient case)," and unidirectionality also rules out an entire range of development types that do not follow this principle, hereby limiting the amount of possible paths of development.