Feasibility of Achieving Effective Closure in the Universe

Determine whether any subsystem of the universe can be treated as effectively closed—meaning isolated from external causal influences—for the purpose of predicting behavior solely from fundamental physical dynamics, in light of sensitivity to distant perturbations (the butterfly effect) and the continual emergence of new causal influences due to the expanding cosmological horizon.

Background

In discussing whether human behavior could, even in principle, be predicted from fundamental physical equations, the paper notes that such predictions presuppose a closed system. To address this, one might attempt to expand the system boundary to achieve effective closure.

However, the author points out two obstacles: sensitivity to initial conditions that allows small, distant events to have large effects (the butterfly effect) and cosmological expansion that continually brings previously unobservable regions into causal contact. These considerations lead to uncertainty about whether effective closure is achievable at all.