Chief amongst the issues Toshihiko Izutsu broached is the philosophisation of Zen Buddhism in his book Toward a Philosophy of Zen Buddhism. This article aims to critically compare Izutsu’s reconstruction of Zen metaphysics with another metaphysical tradition rooted in Descartes’ cogito ergo sum. Putting Izutsu’s terminological choices into the context of Zen Buddhism, we review his argument based on the subject-object distinction and establish a comparison with the Cartesian cogito. A critical analysis is conducted on the functional relationship between subject (...) and object in Izutsu’s metaphysics of Zen. This is examined step by step from the perspective of Descartes’ Meditations. On the one hand, we focus on prima facie similarities in meditative and reflective methodologies used by the Zen and Cartesian approaches. On the other, we highlight some unequivocal differences in the metaphysical role of the subject: an indubitable foundation for the epistemological access to objective reality, and an introspective apprehension of the egoless void or absolute reality. (shrink)