that are elements or properties of all human languages... by necessity." He states that UG expresses "the essence of human language," and believes that the structure-dependent rules of UG allow humans to interpret and create infinite novel grammatical sentences. Chomsky asserts that UG is the underlying connection between all languages and that the various differences between languages are all relative with respect to UG. He claims that UG is essential to our ability to learn languages, and thus uses it as evidence in a discussion of how to form a potential 'theory of learning' for how humans learn all or most of our cognitive processes throughout our lives. The discussion of Chomsky's UG, its innateness, and its connection to how humans learn language has been one of the more covered topics in linguistics studies to date. However, there is division amongst linguists between those who support Chomsky's claims of UG and those who argued against the existence of an underlying shared grammar structure that can account for all languages. Semantics In semantics, research into linguistic universals has taken place in a number of ways. Some linguists, starting with Gottfried Leibniz, have pursued the search for a hypothetic irreducible semantic core of all languages. A modern variant of this approach can be found in the natural semantic metalanguage of Anna Wierzbicka and associates. See, for example, and Other lines of research suggest cross-linguistic tendencies to use body part terms metaphorically as adpositions, or tendencies to have morphologically simple words for cognitively salient concepts. The human body, being a physiological universal, provides an ideal domain for research into semantic and lexical universals. In a seminal study, Cecil H. Brown (1976) proposed a number of universals in the semantics of body part terminology, including the following: in any language, there will be distinct terms for BODY, HEAD, ARM, EYES, NOSE, and MOUTH; if there is a distinct term for FOOT, there will be a distinct term for HAND; similarly, if there are terms for INDIVIDUAL TOES, then there are terms for INDIVIDUAL FINGERS. Subsequent research has shown that most of these features have to be considered cross-linguistic tendencies rather than true universals. Several languages like Tidore and Kuuk Thaayorre lack a general term meaning 'body'. On the basis of such data it has been argued that the highest level in the partonomy of body part terms would be the word for 'person'. Some