June 19, 2021
IT FAILS ON ITS OWN TERMS:
The End of Reductionism Could Be Nigh. Or Not. (SABINE HOSSENFELDER, JUN 18, 2021, Nautilus)
It is certainly true that contemporary physics has shortcomings, quite possibly because the laws that we currently use in physics all work the same way. First, they require us to fully specify the configuration of a system at one moment in time, known as the initial condition. Then, we have an equation--often called the dynamical law or evolution equation--which acts on the initial condition. Finally, by applying the evolution equation to the initial state, we can calculate the configuration of the system at any moment of time. For example, if you specify the position and initial velocity of an arrow, you can use Newton's laws to calculate where it will land.It's turning reductionism on its head.All fundamental theories in physics currently use this division of initial condition and evolution equation. And these theories have gotten us far, but, as Marletto points out, they have limits. The most important one may be that no such theory can ever explain its own initial condition: We have to provide the initial condition as input to make predictions, otherwise we can't calculate anything.
First, pretend that an initial condition exists...
Posted by Orrin Judd at June 19, 2021 12:00 AM
