The civilizational and humanistic significance of writing, one of the greatest inventions in human history, is undisputed. In particular, the various grammatological achievements of interdisciplinary research on the nature, structure, and function of writing over the past half century or so have empirically demonstrated that the function of writing is not limited to the narrow dimension of recording sounds, including spoken language, but is directly related to the creation and transmission of human culture and the enhancement of cognitive abilities. Within the frame of this new grammatological paradigm, the concept and scope of writing extend far beyond the spoken language representations identified by conventional linguistics and include a vast array of fields, such as genetic and cybernetic codes, which can be considered the "letters of life," and the representation systems of the natural sciences, including mathematics and chemistry. In this context, the influence of philosopher Jacques Derrida's 'Grammatology', which emphasized the need to critically reexamine the nature and connotation of writing in a new light and to expand its scope from the traditional grammatology centered on an empirical historical approach, has been decisive for modern humanities and contemporary ideas of writing. In particular, the new kind of writing by artificial intelligence algorithms, which has been witnessed, in recent years, is a revolutionary event in the literary humanities that makes us rethink the production of written language and the agency of human beings at the origin of the exclusive ability of humans assumed in conventional grammatological and narrative studies. It is now at a critical juncture to critically renew the ontological, epistemological, and methodological foundations of traditional grammatology, which are based on the premise of anthropocentrism or human exceptionalism. In this talk, we will try to construct a synthesis of new horizons of grammatology in the 21st century by focusing on three dimensions of writing cosmos, life, and graphism with a transdisciplinary epistemology based upon pluralism, intermediality, and interculturality.