Yasushi Hirai

Professor of Philosophy, Faculty of Letters, Keio University

Philosophy of time and mind, metaphysics of memory, Bergson and Leibniz.

I work on the philosophy of time and mind and on the metaphysics of memory, reading modern and contemporary philosophy with a focus on Bergson and Leibniz.

My central project is to rethink time as a layered structure that incorporates not only extension and tense but also aspect. I build this from a Multi-timescale (MTS) framework and approach consciousness, mind, freedom and memory from within it. I am also interested in reformulating ideas drawn from the classical philosophical texts in the vocabulary of contemporary analytic philosophy and of the sciences.

Books, in Japanese, include The World Is Made of Time: An Introduction to Bergson’s Philosophy of Time (Seidosha), Philosophizing Time: A Toolbox for Thinking (Keio University Press), and Bergson for Beginners: Opening Up Time (Kodansha Gendai Shinsho).

Current research

  • The multi-scale structure of time: a philosophy of time built on extension, tense and aspect
  • The metaphysics of memory: why recollection is not the replaying of a past
  • A theoretical reconstruction of Bergson’s philosophy of time, and its connection to current work on memory and cognition
  • Conceptual history: how technical vocabulary was forged between the sciences and philosophy in the nineteenth century

News

  • 16 October 2026　Talk at the NSYSU Bergson Two-Days Workshop. (National Sun Yat-sen University, Kaohsiung, Taiwan)

  • 6 September 2026　A new paper on the Featured Papers page. Is Bergsonian Freedom Not Deterministic? argues that Bergson’s critique of predictability dismantles not the core claim of determinism but the two assumptions of externality that underwrite predictability — a conceptual excision rather than a refutation (Continental Philosophy Review 58(2), comments on Moravec). Free full text available. Featured Papers

  • 24 August 2026　A new book in Japanese, Bergson for Beginners — Opening Up Time (Kodansha Gendai Shinsho), is out. Publisher’s page

  • 17 August 2026　Built on a multi-timescale reading of Bergson, our co-authored paper System 0/1/2/3: Quad-Process Theory for Multitimescale Embodied Collective Cognitive Systems (Artificial Life 31(4)) is now open access. It extends dual-process theory with System 0 (precognitive embodied processes and morphological computation) and System 3 (collective intelligence and symbol emergence). Read the paper

On this site

Essays for a general readership, in Japanese, appear on note. News and announcements are posted on X (@hiraiyasushi1), mostly in Japanese.

Contact and profiles