Systems comprised of vast numbers of highly interconnected, constantly self-modifying feedback loops exhibit chaotic behaviour. Who'd have thought it?

Ummm...how does that explain sites that stayed more or less with a range for many years? This is what Amit Singhal said, your site is "high quality" one month, junk quality the next and then back to "high quality" and deserving of better rankings without changing a freaking thing. In fact they are sure that they called everyone's demoted site "low quality." That's the truth.