Abstract
At first place the article should serve as clarification of the term "lifeworld" ("Lebenswelt) by means of selected lifeworld-conceptions of 20th. century philosophy.I would like to explikate the attempts of reflexive reference to lifeworld which exist in the concept of Husserl, Heidegger, Wittgenstein and Searle. According to the explanations of Husserl and Heidegger my main interest lies in the problematic of validity. The relation between lifeworld and reflection shall be dealt with in the light of the philosophy of language (Wittgenstein, Searle).At least I would like to discuss the relation between tifeword and science.