 Many researchers—perhaps most—mix elements from each of the three approaches. For example, if Emergentists are to explain the syntactic structure of expressions by appeal to facts about the nature of the use of symbols in human communication, then they will presuppose a great deal of Externalist work in describing linguistic patterns, and those Externalists who work on computational parsing systems frequently use (at least as a starting point) rule systems and ‘structural’ patterns worked out by Essentialists. Certainly, there are no logical impediments for a researcher with one tendency from simultaneously pursuing another; these approaches are only general centers of emphasis.