Hrm. This is why SEO seems like there's a high BS quotient. In some situations, it sounds more like a bunch of norsemen huddled around a fire trying to explain their harsh and unpredictable world via a series of angry and capricious gods, rather than rational, scientific people.
And in many ways, that's how it is - you do some experiments, and by the time you have something definitive (you think, at least), the rules change and your experiments are potentially no longer valid. Even Einstein would be no match for a world where C kept changing at random.
I'd say it's almost exactly how it is. In the natural world, the 'rules' don't change, we just continually discover more, and all the attendant nuances. In the SEO world, Google/Bing/etc really do just change the rules as to how stuff works, possibly because they get angry about abuses going on. There are a small handful of people who control how the online universe largely operates, just like gods.
There's no point in pretending to 'know' things about SEO, because unless you've worked at one of the big search companies, you can't really know what you're talking about. And in the few cases you do, there's no guarantee that the same will hold true tomorrow. In face, the more people 'know' something about SEO, the more likely that particular rule will change.
And no, I don't claim to be an SEO expert - I just tire of hearing the outlandish claims from 'experts' charging gobs of money from unsuspecting hopefuls.
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.
And in many ways, that's how it is - you do some experiments, and by the time you have something definitive (you think, at least), the rules change and your experiments are potentially no longer valid. Even Einstein would be no match for a world where C kept changing at random.