The physics of now

By James B. Hartle. 2004

110 citations recorded by the source corpus.

The world is four-dimensional according to fundamental physics, governed by basic laws that operate in a spacetime that has no unique division into space and time. Yet our subjective experience is divided into present, past, and future. This paper discusses the origin of this division in terms of simple models of information gathering and utilizing systems (IGUSs). Past, present, and future are not properties of four-dimensional spacetime, but notions describing how individual IGUSs process information. Their origin is to be found in how these IGUSs evolved or were constructed. The past, present, and future of an IGUS is consistent with the four-dimensional laws of physics and can be described in four-dimensional terms. The present, for instance, is not a moment of time in the sense of a spacelike surface in spacetime. Rather, there is a localized notion of present at each point along an IGUS’ world line. The common present of many localized IGUSs is an approximate notion appropriate when they are suffici...

Subfields: Atomic and Molecular Physics, and Optics, Cognitive Neuroscience, Molecular Biology

View Paper: https://www.semanticscholar.org/paper/3e197d85f1d20fee38b645523af38c0d954786ee