A model of discrete space-time is presented which is, in a sense, both Lorentz invariant and has no restriction on the relative velocity between particles (except v < c). The space-time has an inbuilt indeterminacy. Published originally as A quanti
sation of time, J. Phys. A: Math. Gen., 10, 2115, 1977; identical to the original, apart from one or two minor corrections, and some simplification towards the end of Section 6. The paper presents a discrete model of time, in which the latter comprises a succession of instants which are identified as collisions with particles called chronons. Proper-time intervals are discrete; the structure of space-time is given by a radar map and has an inbuilt indeterminacy, which leads naturally to Heisenbergs uncertainty principle. If I were writing this paper today I would identify the chronon with the virtual Higgs boson. Without the latter all particles would be massless and would follow null paths; there would be no such thing as proper time. Time is an emergent phenomenon, and the Higgs boson is the agent of that emergence.
