This paper discussed Freud's idea of transience in relation to mortality. Freud's statement about transience appears to have shown his grasp of the dynamic and fluctuating nature of the mind, which Hoffman later characterized as the dialectical-constructivist view. I also indicated that the idea of mujo/transience in Japanese culture has a strong affinity with it. I noted that our acceptance of mortality should also be considered in a dynamic way, as Freud suggested in his essay on transience, where the mind fluctuates constantly between two states: obliviousness and full acceptance of mortality. I then described a case who had a struggle with persistent suicidal ideation after his wife suddenly left him. When he married, he developed a fantasy of reunification with his mother, or felt some kind of eternal bond with her was possible. In our analytic process, he gradually regained the dynamism of his mind with a readiness for the acceptance of the unpredictable fate of himself and others.