Jun Ishiwara was a leading Japanese physicist,but he was also a renowned poet in the early Showa era. Previous studies of Ishiwara rarely linked his literary career with his work as a physicist.The aim of this paper is to demonstrate that his theoretical framework of“reality”was rooted in both science and literature. When Ishiwara introduced Einsteinʼs theory of relativity and quantum mechanics to other writers of his time,he claimed that the development of theoretical physics dismantled so-called orderly reality. According to Ishiwara,if we apply the principles of modern physics to the actual world,we have to understand reality based on“theory”and“law”instead of experience. Therefore,in his literary work,Ishiwara emphasized the“reality”in the former sense of the word: one must extract it from experiences by integrating them into a theoretical framework.As a poet,Ishiwara not only brought“super-materialism”to literature and established“New Tanka theory”,but also contributed to a new way of recognizing the world. His view of the world attracted and influenced many literary figures in the early Showa era such as Riichi Yokomitsu and Yoichi Nakagawa. Ishiwara's interdisciplinary spirit is still present in contemporary literature.(or Ishiwaraʼs interdisciplinarity also offers a fertile ground for constructive dialogue between literature studies and historical studies of science that otherwise rarely interact with one another in the current scholarship).