Unnatural or Natural

Something I've been thinking about for a while, even since before I did the greenwashing article series, is: what makes a thing "natural" or "unnatural"?

Many people would say that "natural" things are things which come from nature with minimal processing. It sounds like a reasonable definition at first glance, but when I try to get specific, I start running into trouble with the definitions of the words used to define "natural". They seem to be a bit fuzzy themselves, which makes the term "natural" hard to pin down.

So my first question is, what is meant, exactly, by "from nature"?