oxforddictionaries.com gives the definition of “Random” as
1. made, done, or happening without method or conscious decision
2. informal. odd, unusual, or unexpected
It gives the relevent definition of “Arbitrary” as
1. based on random choice or personal whim, rather than any reason or system
Well, I don’t think I’ll be choosing the questions I ask and answer on this blog without method or conscious decision…it will be more like personal whim, or random choice amoung a few suggestions.
Any reason or system involved? Reason, possibly, although still probably based on personal whim. Overall I doubt a system, but there may be some in choosing the order of entries etc.
On the other hand, I’m certainly hoping that many of these questions will be odd, unusual, or unexpected.
In essense, “arbitrary” would probably be more correct as precise language, although informally “random” gets the correct idea across in a reasonable tone of voice, as it were (unless you’re reading this as a mathematician).
So I think the correct answer should depend on whether we think language should be a precisely defined construct, or is mostly about communicating ideas to others.
Language, then: fixed or fluid?