is debate about whether the Minimalist Program is motivated by the empirical shortcomings of P&P or whether it is motivated by ideological concerns with 'elegance' etc. (see main article on the Minimalist Program). Aside from this major move within the discipline, it seems that consensus has not been achieved over a list of universal parameters. Certainly, there is no publicly available list of these parameters and textbooks tend to cite the same ones: the interrelated verb-movement parameters (V-v, V-T, T-C), noun-movement parameters (N-D), subject-related parameters (pro-drop and EPP) and headedness parameters. This is not to say that the theory has not been fruitful (e.g. Holmberg and Platzak’s comprehensive analysis of parametric variation in Scandinavian languages), or that the theory is not descriptively adequate, but rather that the accomplishments of this line of thinking have been less than anticipated in terms of explanatory adequacy. Particularly, a systematic, predictive system of parameters, their properties and interactions, along the lines of the periodic table in chemistry, has yet to be developed. Generally, theorists have moved to regarding parameters as varying feature specifications on lexical items within languages and derivations rather than parameters which are globally defined. For example, while formal linguistics takes the sentence to be the canonical unit of analysis, conversation analysis (CA) takes the turn at talk as canonical. Speakers in conversation often do not use complete sentences or even complete words to converse. Rather, discourse is composed of sequences of turns which are composed of Turn construction unit (e.g. a word, phrase, clause, sentence). In CA, the form and meaning of an utterance is a product of situated activity- which is to say meaning is highly contextual (within a social, interactive context) and contingent upon how participants respond to each other regardless of grammatical completeness of an utterance. Similarly, other discourse and corpus linguistic analyses have found recursion and other forms of grammatical complexity to be rather rare in spoken discourse (especially in preliterate societies) but common in written discourse suggesting that much of grammatical complexity may in fact be a product of literacy training. Other critics point out that there is little if anything that can unequivocally be called universal across the world's languages. Discourse analyses have focused on the dynamic, dialogic, and social nature of language use in social situations. These critics argue that P&P and discourse analysis differ in the same way that chemistry and cookery differ: