To what extent can anything be unnatural if every substance initially came from the earth to begin with? Wouldn't that make all things natural? A colleague of mine reminded me that there are ways to alter different things, but does that make it unnatural if the process by which we have altered a substance is natural? Such alterations exist via heat (natural), combining with another substance (which is also natural) to cause a reaction, and so on... But what makes something (a product of a reaction, perhaps) unnatural? Say reactant A, which is natural, is combined with reactant "B", which is also natural, to create a product which we would call unnatural. How can we call the product of two natural substances unnatural?
To make a long question short, what is the difference between natural and unnatural? Keeping in mind that all things are naturally found on earth. What makes something "artificial"?