ContactPerson: hismail@cse.buffalo.edu ### Begin Citation ### Do not delete this line ### %R 2001-08 %U /home/csgrad/hismail/public_html/clock.ps %A Ismail, Haythem O. %A Shapiro, Stuart C. %T The Cognitive Clock: A Formal Investigation of the Epistemology of Time %D August 14, 2001 %I Department of Computer Science and Engineering, SUNY Buffalo %K Temporal reasoning, cognitive robotics, knowledge representation %Y I.2.4 %X We present a formal model of time and time perception. The model is used to endow a cognitive agent with a personal sense of time. A personal sense of time is based on a representation of the real-time present that allows the agent to distinguish it from the past and the future, and is continuously changing to reflect the progression of time. This is important for reasoning about, and acting in, dynamic domains and for interacting with other agents (humans, for example). An agent that interleaves reasoning and acting while maintaining a sense of the present faces what has been dubbed {\em the problem of the fleeting now}. A solution to the problem involves, not only endowing the agent with a sense of temporal progression, but also with a feel for how much time has passed. In this paper, we construct a theory of time that allows just that.