:	StephenWolfram terms the inability to shortcut a program (e.g., a system), or otherwise describe its behavior in a simple way, "ComputationalIrreducibility". The empirical fact is that the world of simple programs contains a great diversity of behavior, but, because of undecidability, it is impossible to predict what they will do before actually running them.

from http://en.wikipedia.org/wiki/Computational_irreducibility