Warum hat Zeit eine Richtung?

Abstract

A surprising finding of physics is that the ubiquitous observation of physical processes which are irreversible, like the dissolution of a substance in a liquid, have no counterpart in the microscopic laws in physics which indicate that time is directionless and allow for a reversal of the direction of time. This seemingly negates our empirical observation that an open future contrasts with a fixed past. The existence of a direction or arrow of time is explained in modern physics as a statistical phenomenon: while at the microscopic level reversibility holds, at a macroscopic level the numbers of microscopic arrangements that correspond to one macroscopically observable state of the world are so vastly different that a statistical drift from less likely to more likely states turns into deterministic evolution. The direction of time is therefore an emergent phenomenon upon the advent of complexity in macroscopic physical systems. Various arguments have been raised against this picture, but can be shown to be either empirically irrelevant or, more interestingly, to be refuted by the coarse graining or summarizing of world information that is a key aspect of human perception – which finds its motivation in symmetries and almost constant quantities in physics.

Keywords

• MPIeR