How can one define what's natural and what's unnatural?

Question

I think everything that actually exists is natural. From planets, forests to computers. (Ultimately it's all a product of nature.)

But in practical conversations unnatural began meaning artificial. So, why do we need the word natural/unnatural as in (non)artificial and what exactly does it mean?

Or is it's meaning in such usage rather arbitrary than established?

Answer 1

Ok, the word nature means the material world and everything in it. Of course we can take that and make the word natural. But as such, it doesn't really have an opposite called 'unnatural'. The opposite of that would be 'spiritual', or sometimes 'fictitious'. The word unnatural is the opposite of natural when it has some other meaning, like 'taking place in conformity with the ordinary course of nature', or 'closely imitating nature', or 'not artificially made or constructed; not manufactured or processed' and so on. So when somebody calls something unnatural, you can not take it to mean that he thinks it exists outside of nature (which is impossible for a material object), you have to assume he means something else (like 'artificial').

To answer your questions, "why do we need the word natural/unnatural as in (non)artificial": because it is useful, and fairly unambiguous.

"Is it's meaning in such usage rather arbitrary than established?" It is based on one of the many meanings of the word 'natural'.