Using the Instant for the Projects of Science. Focusing on Bachelard's books L'Intuition de l'instant (1932) and La dialectique de la durée (1936), the paper deals with Bachelard's discontinuous and serial concept of time that is formulated against Henri Bergson's concept of duration. With a view to the philosophical concept of monadology, to the theory of relativity, and to the contemporary psychological and neurological research, the paper points to the significance of the instant for Bachelard's concept of temporality, for his desubjectified concept of the individual as well as his discontinuous concept of matter. Moreoever, the paper explores the discontinuous conception of temporality in Bachelard's epistemological writings. The paper argues that Bachelard's discontinuous concept of the specific temporality of science is based on a fundamental discontinuity of reality of both physical as well as psychological processes.