fast
Contributor
Not arbitrary. We looked up and saw similarities in nature, similarities that were there before we looked. They were there for the discovery. We later invented a word (and maybe that was arbitrary), but it refers to an aspect of nature, just like the older definition "planet" referred to an aspect of nature."Planet" is a category. Not a specific entity.
An arbitrary, artificial, man-made category.
We created the name for the categories. Category potentials are endless. They exist independent of human creation.