The opening chapter sets out why the variability of speed and duration should underpin the study of aesthetics and the philosophy of art. The discussion begins with Leibniz’s division between distinct and confused perception, which was also adopted by Baumgarten to justify separating aesthetics from metaphysics. These perceptual differences are framed in terms of scale whereby vision and hearing contract the plenitude of the petites perceptions into recognisable surfaces, patterns and forms. Such contraction also concerns time, for a percipient can only discriminate between sensual data whose speed does not exceed certain temporal thresholds, consequently, the perception of qualia depends on durational differences. In addition to qualia, speed and duration also feature in the material constitution of a work or performance, with each artwork comprising multiple speeds delimited by the material and representational properties of the medium. This is examined through the medium of photography, in which, depending on the duration of exposure, objects lose their outlines, processes disappear, and backgrounds blur, which was of particular interest to early photographers due to the slow exposure times. Attending to these durational differences in both the medium and perception reveals a processual metaphysics underpinning ostensibly substantive phenomena.