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Why Synchronized Time is a Fiction: Daylight Saving Time, Leap Seconds, and the Guillotine Sharpened for Nothing

Paul Borrill

Abstract

Civilization maintains an elaborate infrastructure devoted to the maintenance of synchronized time. Governments mandate daylight saving time. Standards bodies insert leap seconds into Coordinated Universal Time. Engineers debate leap milliseconds and leap nanoseconds. The Global Positioning System applies relativistic corrections at the nanosecond level. All of these adjustments attempt to preserve an assumption: that a single global time exists and that clocks can be made to agree upon it. This paper argues that this assumption constitutes a category mistake in the sense of Ryle (1949). We show that special and general relativity prohibit absolute simultaneity, that the one-way speed of light is conventionally defined rather than measured, and that recent experiments on indefinite causal order demonstrate nature admits correlations with no well-defined temporal sequence. We trace the consequences of this category mistake through distributed computing, where it manifests as the Forward-In-Time-Only (FITO) assumption that underlies Lamport's logical clocks (1978), the impossibility results of Fischer-Lynch-Paterson (1985), and the CAP theorem (2000). From this perspective, daylight saving time and leap seconds are not corrections to time but corrections to conventions -- they sharpen the guillotine of synchronization in preparation for executing something that does not exist.

Why Synchronized Time is a Fiction: Daylight Saving Time, Leap Seconds, and the Guillotine Sharpened for Nothing

Abstract

Civilization maintains an elaborate infrastructure devoted to the maintenance of synchronized time. Governments mandate daylight saving time. Standards bodies insert leap seconds into Coordinated Universal Time. Engineers debate leap milliseconds and leap nanoseconds. The Global Positioning System applies relativistic corrections at the nanosecond level. All of these adjustments attempt to preserve an assumption: that a single global time exists and that clocks can be made to agree upon it. This paper argues that this assumption constitutes a category mistake in the sense of Ryle (1949). We show that special and general relativity prohibit absolute simultaneity, that the one-way speed of light is conventionally defined rather than measured, and that recent experiments on indefinite causal order demonstrate nature admits correlations with no well-defined temporal sequence. We trace the consequences of this category mistake through distributed computing, where it manifests as the Forward-In-Time-Only (FITO) assumption that underlies Lamport's logical clocks (1978), the impossibility results of Fischer-Lynch-Paterson (1985), and the CAP theorem (2000). From this perspective, daylight saving time and leap seconds are not corrections to time but corrections to conventions -- they sharpen the guillotine of synchronization in preparation for executing something that does not exist.
Paper Structure (19 sections, 14 equations, 4 figures)

This paper contains 19 sections, 14 equations, 4 figures.

Table of Contents

  1. Introduction
  2. Three Competing Definitions of Time
  3. Leap Seconds: Correcting a Convention
  4. Daylight Saving Time: The Convention Made Explicit
  5. Einstein Synchronization and the One-Way Speed of Light
  6. Lewis & Barnes: The Cosmological Proof
  7. The Photon's Perspective
  8. Indefinite, Not Infinite
  9. The Relativity of Simultaneity
  10. The Clock Synchronization Hypothesis and the Stanford Data
  11. Bell's Theorem and Indefinite Causal Order
  12. The Bell Test Circularity
  13. Distributed Systems and the fito Assumption
  14. IEEE 1588 and the Precision Illusion
  15. Timestamps Are Contracts, Not Truth
  16. ...and 4 more sections

Figures (4)

  • Figure 1: Space-time diagrams for isotropic (left) and extreme anisotropic (right) one-way speed of light. Green dashed lines: future light cones. Grey lines: worldlines of massive objects. Blue lines: light emitted after equal proper time. In both cases, the observer at the origin sees the same universe. From Lewis & Barnes lewis2021, Figure 1.
  • Figure 2: Lines of simultaneity in the emitter's FRW coordinates, mapped into anisotropic velocity-of-light coordinates from $\kappa = 0$ (isotropic, hyperbola) to $\kappa = 1$ (extreme anisotropic, bold red), with intermediate cases in steps of $\kappa = 0.2$ (lighter red). The filled circles mark the emitter's location for each case. The spatial position in the $\tilde{R}$ coordinate is independent of $\kappa$---only the simultaneity surface deforms. From Lewis & Barnes lewis2021, Figure 5.
  • Figure 3: The conventionality of simultaneity: for spacelike-separated events, different inertial observers disagree on which event occurred first. The "hyperplanes of simultaneity" that the clock synchronization hypothesis presupposes (Definition \ref{['def:clock-sync-hypothesis']}) are observer-dependent constructions, not objective features of spacetime.
  • Figure 4: Bounds on timestamp discrepancy from the Stanford nanosecond synchronization measurements (reproduced from Geng et al., NSDI 2018, Figure 4). The thick blue and green lines represent the minimum spacetime intervals between sending and receiving timestamps. Points appearing within the "forbidden zone" between these bounds were classified as measurement errors. We argue they validate the relativity of simultaneity. Note the vertical axis: the discrepancies are measured in microseconds ($\mu$s), yet the Stanford paper claims nanosecond synchronization accuracy---three orders of magnitude smaller than the anomalies being discarded. The "forbidden zone" is not at the edge of the measurement noise floor. It is a thousand times larger than the claimed precision.

Theorems & Definitions (2)

  • Definition 7.1: The Clock Synchronization Hypothesis
  • Definition 9.1: Forward-In-Time-Only (fito)