PUBLIC TALK: How to define time without presupposing time?

A public lecture by Paul Baird, Professeur Classe Exceptionnelle, Universite de Bretagne Occidentale, Laboratoire de Mathematiques de Bretagne Atlantique

This question is the last of J. A. Wheeler's four puzzles that challenge our conception of the world. We have a profound sense that somewhere, somehow, there is a universal clock ticking away. The sun rises and sets to define a day, electronic transition frequencies are the basis of the most accurate timepieces ever constructed, our watch tells us that it's almost six o'clock and time for the news and if we have any doubt, we turn on the TV. The rhythms of our lives reinforce our belief in the universal timepiece. But if we examine more closely the notion of time, particularly at the extremes, we may become a little uneasy.

Professor Baird will examine the prejudices that we as humans have, existing somewhere mid-scale in the gradation of universal structure, notably those of space and time. To do this, he will introduce an elementary model universe based on basic information-theoretic principles: yes-no responses. Geometry emerges from such a universe, but change is trickier to deal with. What does change mean and what determines a causal sequence of events? Recent work on the reconstruction of quantum mechanics, with its analysis of causal games, challenges the assumption of a global causal structure. Professor Baird will discuss his own interpretation of causal games by introducing the notion of temporal state. The realization and survival of these states, he argues, produces an unstoppable train. Time.

Cost: FREE but RSVP requested via the website