Fascinating. I had always assumed that "Arena" was indeed based on the Brown story, probably because the 1973 David Gerrold book stated it as a fact: "And one of the scripts was based on a short story by Fredric Brown."
Ah, interesting. Which book, by the way? There are two Gerrold Star Trek
books from 1973: The World of Star Trek
and The Trouble with Tribbles.
And, do you have a page number?
Sorry, I meant The World of Star Trek.
I'm not home right now, but the quote can be seen at Google Books on page 243 (http://books.google.com/books?ei=d-I...#search_anchor