to exhibit universal and non-obvious similarities? According to this framework, principles and parameters are part of a genetically innate universal grammar (UG) which all humans possess, barring any genetic disorders. As such, principles and parameters do not need to be learned by exposure to language. Rather, exposure to language merely triggers the parameters to adopt the correct setting. The problem is simplified considerably if children are innately equipped with mental apparatus that reduces and in a sense directs the search space amongst possible grammars. The P&P approach is an attempt to provide a precise and testable characterization of this innate endowment which consists of universal "Principles" and language-specific, binary "Parameters" that can be set in various ways. The interaction of the principles and the parameter settings produces all known languages while excluding non-natural languages. Criticisms Criticism of the P&P approach has come from a number of quarters, but with varying impact. These can be subdivided into three main groups. Theory internal critique The lack of consensus on a set of parameters Inter-paradigm critiques not specific to P&P Perhaps the most influential criticisms of P&P have been theory internal. As in any other developing field of enquiry, research published within the P&P paradigm often suggests reformulations and variations of the basic P&P premises. Notable debates emerged within P&P including (a) derivationalism vs representationalism (b) the locus of morphology (e.g. lexicalism vs derived morphology) and (c) the tension between a production model and a competence model amongst others. The development of head-driven phrase structure grammar (HPSG) and lexical functional grammar (LFG) reflect these debates: these are both strongly lexicalist and representational systems. Nevertheless, perhaps the most coherent and substantial critique of P&P is the Minimalist Program, Noam Chomsky's most recent proposal. This program of research utilizes conceptions of economy to enhance the search for universal principles and parameters. Linguists in this program assume that humans use as economic a system as possible in their innate syntactic knowledge. The Minimalist Program takes issue with the large number of independent postulations in P&P and either (a) reduces them to more fundamental principles (e.g. Merge, Move, Agree), (b) derives them from 'reasonable' interface constraints on derivations (e.g. bottom-up Merge and requirement that no derivation be counter-cyclic derives Relativized Minimality effects) or (c) programmatically suggests that they be either derived from more basic principles or eliminated subject to future research (e.g. Binding Principles). Note that there