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The Semantic Arrow of Time, Part I: From Eddington to Ethernet

Paul Borrill

TL;DR

The FITO assumption is not a law of nature but a design choice, and recognizing this dissolves apparent constraints that have shaped forty years of distributed systems theory.

Abstract

This is the first of five papers comprising The Semantic Arrow of Time. The argument begins with a claim: computing's arrow of time is semantic, not thermodynamic. The direction in which meaning is preserved or destroyed across transactions is not a consequence of the second law but of design choices embedded in protocol architectures since Shannon's 1948 channel model. These choices encode the Forward-In-Time-Only (FITO) assumption -- the commitment that causation is irreversible, acyclic, and globally monotonic. We trace this assumption from Eddington's 1927 coinage of "the arrow of time," through the Boltzmann--Loschmidt debate, to contemporary philosophy of physics: Price's time-symmetric ontology, Smolin's temporal naturalism, Rovelli's relational quantum mechanics, and Roberts's analysis of time-reversal symmetry. We show that fundamental physics is time-symmetric at the microscopic level, that the thermodynamic arrow emerges from boundary conditions rather than fundamental law, and that recent demonstrations of indefinite causal order confirm nature admits correlations with no well-defined temporal ordering. We then identify the category mistake (Ryle, 1949): computing inherited Newton's absolute background time -- via Shannon, Lamport, and the impossibility theorems -- and encoded it as a semantic primitive. The FITO assumption is not a law of nature but a design choice, and recognizing this dissolves apparent constraints that have shaped forty years of distributed systems theory. Subsequent papers develop the constructive alternative through link semantics, RDMA, transaction failures, and the Leibniz Bridge framework.

The Semantic Arrow of Time, Part I: From Eddington to Ethernet

TL;DR

The FITO assumption is not a law of nature but a design choice, and recognizing this dissolves apparent constraints that have shaped forty years of distributed systems theory.

Abstract

This is the first of five papers comprising The Semantic Arrow of Time. The argument begins with a claim: computing's arrow of time is semantic, not thermodynamic. The direction in which meaning is preserved or destroyed across transactions is not a consequence of the second law but of design choices embedded in protocol architectures since Shannon's 1948 channel model. These choices encode the Forward-In-Time-Only (FITO) assumption -- the commitment that causation is irreversible, acyclic, and globally monotonic. We trace this assumption from Eddington's 1927 coinage of "the arrow of time," through the Boltzmann--Loschmidt debate, to contemporary philosophy of physics: Price's time-symmetric ontology, Smolin's temporal naturalism, Rovelli's relational quantum mechanics, and Roberts's analysis of time-reversal symmetry. We show that fundamental physics is time-symmetric at the microscopic level, that the thermodynamic arrow emerges from boundary conditions rather than fundamental law, and that recent demonstrations of indefinite causal order confirm nature admits correlations with no well-defined temporal ordering. We then identify the category mistake (Ryle, 1949): computing inherited Newton's absolute background time -- via Shannon, Lamport, and the impossibility theorems -- and encoded it as a semantic primitive. The FITO assumption is not a law of nature but a design choice, and recognizing this dissolves apparent constraints that have shaped forty years of distributed systems theory. Subsequent papers develop the constructive alternative through link semantics, RDMA, transaction failures, and the Leibniz Bridge framework.
Paper Structure (19 sections, 1 theorem)

This paper contains 19 sections, 1 theorem.

Table of Contents

  1. Introduction: The Two Arrows
  2. Eddington's Legacy: The Thermodynamic Arrow
  3. The Case for Time-Symmetric Ontology
  4. Smolin's Temporal Naturalism
  5. Rovelli's Relational Time
  6. Indefinite Causal Order
  7. The Category Mistake: From Physics to Computing
  8. Stage 1: Shannon's Channel (1948).
  9. Stage 2: Lamport's Happened-Before (1978).
  10. Stage 3: The Impossibility Theorems (1982--2002).
  11. The Leibnizian Principle Applied
  12. The Semantic Arrow Defined
  13. The fito Assumption in Computing
  14. Timeout-and-Retry (TAR).
  15. Clock Synchronization.
  16. ...and 4 more sections

Key Result

Proposition 8.1

If two distributed system states are empirically indistinguishable at every node---if no observation by any participant can distinguish them---but the formal model assigns them different causal histories, then the model contains surplus ontological structure.

Theorems & Definitions (2)

  • Proposition 8.1: Surplus Structure in fito Models
  • Definition 9.1: The Semantic Arrow of Time