# The frame within the game within the frame

entropy is *essential ignorance*. entropy is the premise underlying all Bayesian analysis. entropy is the portion of a system state an observer does not or cannot know a priori.

The popular science definition of entropy is strongly misleading. Something that seems to the human mind very disordered such as the fractal sets of Mandelbrot and Julia, or the output of pseudo-random number generators are actually very *low* entropy systems - apparent complexity is NOT high entropy.

complexity is an amplifier of small amounts of ignorance.

The butterfly effect in climate dynamics is due to complexity, not to randomness or essential ignorance. Though cause is non-random and known, we cannot bound its effects thousands of miles away because of essential complexity.