In the fiftieth disputation of his Disputationes metaphysicae (1597), Francisco Suárez distinguishes three notions of time. Suárez offers an account of the ways in which the predicate ‘when’ can be taken and presents a more general perspective based on the principle of duration, rather than the Aristotelian definition of time. His view differs from Aristotle’s and Aquinas’ account because Suárez emphasizes that time cannot be reduced to the number of the movement of the last sphere in the Aristotelian model of (...) the cosmos. The intrinsic duration of a thing is its true time; this duration can be taken in an absolute or a relative sense. In an absolute sense, intrinsic time is an internal property of a thing that cannot be really distinguished from existence itself and cannot be compared with other durations. In a relative sense, we can imagine this intrinsic duration as filling up a certain interval within an infinitely extended imaginary succession. This imaginary succession is an ens rationis. The third concept of time is the Aristotelian notion: this is just an extrinsic time, a measurement of one movement by means of a comparison with another movement, especially the motion of the last sphere. Finally, in order to show the value of Suárez’s insights, I compare them with some contemporary issues in the analytic philosophy of time. (shrink)