 As in the Greek tradition, the positing of atoms in Islamic thought was paired with assertions about the existence of void space, in opposition to the continuum physics characteristic of most falsafa thought (cf. Pines 1979). Debate over the existence of void was enriched by the need to explain the operation of so-called pneumatic devices like the siphon, medical cupping glasses or syringe (Lugal and Sayili 1951; Koetschet 2019). The supposed impossibility of void space forming was used to account for observed fluid movements in pneumatic devices, raising questions about how a metaphysical impossibility might produce physical motions. Ingenious thought experiments were developed to test the assumptions at work, asking what would happen if a single film of atoms were trapped between two cupping glasses, or comparing the effect of cupping glasses on stone to their effect on flesh (Dhanani 1994, 77). The fascination with pneumatic technology in the medieval Islamic world is attested in surviving texts which detail increasingly complex marvels: trick fountains, surprise vessels, water clocks with elaborate mechanical side-shows (Hill 1974, 1979), although the explanation of these effects did not necessarily involve atomist or particle theories of matter. 