Leibniz’s Metaphysics of Change: Vague States and Physical Continuity

In this paper I examine Leibniz’s writings with a view to making precise his complex views on duration and change. Leibniz seems firmly committed to two contradictory claims: that the Law of Continuity holds everywhere, so that there is no change by a leap; and that in actuality, all change is discontinuous, so that duration is an aggregate of momentary states. I attempt to explain his thinking on temporal continuity by examining the origins of his view of change, as expounded in his early dialogue, the Pacidius Philalethi, showing how this necessitates the introduction of monads as substantial continuants. I then explain, with special reference to a recently transcribed unpublished manuscript, how Leibniz finesses the discrepancy between the mere physical continuity of the actual and the ideal continuity of mathematics by appeal to his conception of the foundations of the calculus.