ETYMOLOGY & DICTIONARY

Artificial: Late XIV c., "made by man" (opposite of natural), from French Origin "Artificielle", from Latin "Artificialis": "of or belonging to art", "from artificium". Another early use was in the phrase artificial day "part of the day from sunrise to sunset". [Taken from Dictionary Reference, 13/10/2010, http://dictionary.reference.com/etymology/artificial]

Natural:  "Nature" refers to the phenomena of the physical world, and also to life in general. It ranges in scale from the subatomic to the cosmic. The word nature is derived from the Latin word natura, or "essential qualities, innate disposition", and in ancient times, literally meant "birth". Natura was a Latin translation of the Greek word physis (φύσις), which originally related to the intrinsic characteristics that plants, animals, and other features of the world develop of their own accord. The concept of nature as a whole, the physical universe, is one of several expansions of the original notion; it began with certain core applications of the word φύσις by pre-Socratic scientific method in the last several centuries. philosophers, and has steadily gained currency ever since. This usage was confirmed during the advent of modern. [Taken from Wikipedia, 13/10/2010, http://en.wikipedia.org/wiki/Nature]