  The Master Argument for determinism continued to exercise Prior for the rest of his life, and some of the most useful and mathematically most interesting parts of his work were inspired by his thoughts on it. To pick just one example, from computer science, tense calculi that Prior developed—leading on from the idea that the Master Argument is defeated if time is conceived as branching into the future—have become useful for describing and verifying the behaviour of distributed and concurrent processing systems (see e.g. Ben-Ari, Pnueli, and Manna 1983).