Longitude and Simultaneity in Philosophy, Physics, and Empires

The finding of longitude on the oceans was considered the greatest scientific challenge between the sixteenth and eighteenth centuries. This essay sketches its impact on the establishment of the British Empire, Victorian physics, and the early philosophy of Martin Heidegger. Against the backdrop of this history, a historical ontology of the clock is developed. While the clock was a machine during the Middle Ages, it turned into an instrument in early modern times, and into a medium during the nineteenth and twentieth centuries. As a medium for the Dasein, the clock is not only an ontic measuring instrument, but also an ontological thing, which for the Dasein makes accessible the technicality of its own being.