The term live is generally understood in the sense of “immediate,” or to indicate the fact that something takes place here and now. The fact that some events are perceived as live undoubtedly indicates something significant about those events. Still, scholarship in performance studies and neighboring fields have demonstrated that a simple, ontological, or technical definition of liveness is problematic if not impossible. This study rethinks the meaning of liveness, proposing that liveness pertains to the manner in which something is perceived and to what is perceived in that thing. Based on a reassessment of key conceptualizations of liveness and presence in performance studies, it develops an understanding of liveness as the characteristic of a sense-making that affirms difference, and which presupposes mediation rather than implying immediacy. The dynamics of this live sense are further developed through a consideration of the artistic treatises of Japanese nō actor and playwright Zeami (c. 1363 – c. 1443). These texts demonstrate how secrecy or not knowing is a precondition to produce a sense of liveness for the audience, expressed by the concept hana, the “flower.” The dissertation argues that this sense of secrets is significant for the artistic process as well, and that it relates to larger questions regarding understanding, aesthetics and the nature of reality. Then in the last chapter, the study takes up three examples of film, nō theater and pop music, exploring how a liveness that is objective and universal comes to be experienced subjectively in particular encounters of different kinds. In this way, the thesis as a whole provides a way of understanding liveness as the appreciation of the ineffable: a theoretical framework which serves both to analyze specific experiences and to shed light on the live foundation of sense-making as such.