---
title: "A Common-Sense Theory of Time"
authors:
  - "James F. Allen"
  - "Patrick J. Hayes"
doi: ""
url: "https://ijcai.org/proceedings/1985/101"
pdf: "https://ijcai.org/proceedings/1985/0101.pdf"
venue: "Proceedings of the Ninth International Joint Conference on Artificial Intelligence"
year: 1985
pages: "528-530"
track: "Knowledge Representation"
keywords:
---

# A Common-Sense Theory of Time

James F. Allen, Patrick J. Hayes

*Proceedings of the Ninth International Joint Conference on Artificial Intelligence*, pages 528-530.

## Abstract

The literature on the nature an d representation of time is full of disputes and contradictory theories. This is surprising since the nature of time does not cause any worry for people in their everyday coping with the world. What this suggests is that there is some form of common sense knowledge about time that is rich enough to enable people to deal with the world, and which is univer sal enough to enable cooperation and communication between people. In this paper, we propose such a theory an d defend it in two different ways. We axiomatize a theory of time in terms of intervals a nd the s ingl e relation \1 FET. We then show that this axiomatization subs ume s Allen·s interval-based the ory. We then exte nd the theor) by formally defining the begi nnings and endings of interva ls and show that these ha ve the pr operties we normally ''o uld associate wit h points. We distinguish between these point-like objects and the concept of moment as hypothesi ze d in di sc rete time mo dels. Finally, we exa mine the theory in terms of eac h of several different models.