Yasushi Hirai (1971–) is a Japanese philosopher and professor at Keio University. After studying oil painting at Musashino Art University, he pursued philosophy at Tokyo Metropolitan University. His research focuses on modern and contemporary philosophy, particularly Henri Bergson and Gottfried Wilhelm Leibniz, as well as the philosophy of time and mind and the metaphysics of memory. He connects ideas from the history of philosophy with contemporary analytic philosophy and cognitive science. In “Sekai wa Jikan de Dekiteiru: Berukuson Jikan Tetsugaku Nyumon” (The World Is Made of Time: An Introduction to Bergson’s Philosophy of Time), he presents time not as a single uniform sequence but as a multilayered structure composed of interacting rhythms and scales.