Star Trek Season 1 Episode 21

The concept of "Festival" was never explained within the show. It's certainly not necessary to explain everything, and in fact one of Star Trek's strengths was its often tacit assumption that the viewers could figure some things out for themselves. However, one wonders how "Festival" advanced the plot -- why include it at all? There was certainly ample evidence that something unusual was going on prior to this. In his adaptation of the episode, James Blish did provide an explanation. His explanation: Landru's idyllic society lacked population control, so Festival was conceived as an answer, the sort of solution a machine without soul or wisdom might create.