Biosemiotics is the study of meaning in living systems; it is about context dependent communication and signification on all levels of biological organization. Thereby, biosemiotics perceives the concept of meaning as an essential, non-reducible characteristic of the living world; without it, the latter cannot be understood in a reasonable way. But this position is in conflict with the standard classical stance of natural science (though, of course, not with the one of social sciences). Accord-ing to this perspective, the idea of meaning can only be consid-ered as a kind of metaphorical use of language (due to our cognitive inability in terms of a complete reduction). This article gives some indications, how biosemiotics can defend and justify its position form a metatheoretic and philosophic point of view. Though, meaning is so evident and, hence, a basically real fact in living systems, we nevertheless need a sound scientific foundation for its argumentation.