Clocks Between Ticks: Latest Ticks, Stopping Times, and the SR– QM Interface

A recent clock-based proposal in the foundations of quantum theory takes seriously the idea that physical time is grounded in concrete ticking systems and their records, rather than in an alreadycomplete spacetime manifold. In that framework, the “latest tick” of a clock plays a central conceptual role: it marks the upper edge of the clock’s realised history, anchors local present-like bands, and is used to articulate relational views of nonlocal correlations in Bell-type scenarios. But as it stands, this notion is treated too loosely to bear the weight placed upon it. This paper offers a modest clean-up. First, we distinguish three levels at which the latest tick operates: (i) the level of isolated physical systems (oscillators, cycle-to-event converters, recording subsystems, and start/stop mechanisms), (ii) the level of theoretical representation in special relativity and standard quantum mechanics (proper-time worldlines, survival amplitudes and waiting-time distributions), and (iii) an explicitly interpretive level where claims about becoming, presentness, and nonlocality are made. Second, we introduce a minimal stopping-time formalism in which the ticking of a clock is modelled as a proper-time point process that may terminate, so that the latest tick becomes a stopping-time–conditioned event rather than an informal label. Third, we apply this framework to Schrödinger’s cat, treating the experiment as a network of clocks and stopping processes rather than a single macroscopic two-state system, and we argue that the latest tick, thus formalised, is a natural interface object between relativistic proper time and quantum decay time. The aim is not to propose a new dynamics, but to improve the conceptual clarity around clocks so that questions about quantum Zeno behaviour, real-clock approaches to the measurement problem, and relational interpretations can be posed more sharply.