Metaphor has been elevated and absolutized, but also exhausted and problematized in modernity. Above that, the language sign/symbol has been revealed as arbitrary and functional wherever imagination has failed. Metaphor exploits external or situational analogy, which is not arbitrary, if we consider it within a communicative situation. For this reason, metaphor has been pushed out of the focus of linguistics. Postmodern resignation to consistency and completeness of explanation has led to using metaphors – otherwise irreplaceable in forming new ideas and experiences – instead of definitions of concepts. We want to show that concepts can and should be analysed and defined. We propose that one can analyse in this way the problem of universal grammar and recursion in language. Reflecting on the function of metaphor in philosophy, we show that philosophical explanations are applicable in other disciplines dealing with language and communication.