I have rewatched a number of Star Trek: The Next Generation episodes in quick succession over the past week. One thing I observed that I hadn't before is that the number 47 seems to come up unnaturally often, at least at first glance. I then sampled the episode scripts to produce a list of all occurrences — 203 verbal ones, including variations such as 4-7 and four 7's, as well as appearances within longer numbers (e.g. 247, 0.047).
- "Tin Man" : The Ghorusda incident claims the lives of 47 people.
- "Family" : Picard receives a bottle of the '47 wine from Robert as a gift.
- "The Loss" : The Enterprise-D will arrive at T'lli Beta in 6 days, 13 hours, 47 minutes.
- "In Theory" : The Enterprise-D is 4.7 million km from the edge of a certain nebula.
- "Darmok" : The word "Darmok" appears 47 separate times in the ship's library.
- "The Game" : Nurse Ogawa tells Wesley that she is currently at level 47 of the Ktarian game.
- "Conundrum" : A holodeck program numbered 47C is activated. Later, there are 47 sentries guarding the Lysian Command.
- "I, Borg" : The geometric paradox virus is called "Topological Anomaly 4747" on the display screen.
- "Time's Arrow" : Picard uses phaser setting 0.47 to open the gateway.
- "True Q" : Amanda Rogers is on section 4 of deck 7. Data later remarks that the temperature inside the reaction chamber has increased by 47 percent.
- "Birthright" : The length of time for which Data is unconscious is 47 seconds.
- "Frame of Mind" : Riker is a patient in Ward 47.
- "Timescape" : Data remarks that one of the nacelles has been operating continuously for 47 days.
- "Descent" : Stephen Hawking's hand consists of four 7's, and he subsequently wins the poker game.
- "Parallels" : Starbase 47 is mentioned.
- "Genesis" : The authorization code is Alpha-4-7.
These are only a selection. On top of the many verbal occurrences, I suspect that there are a number of additional non-verbal occurrences where the number 47 flashes on a display screen or PADD, etc. (as in the geometric paradox example above).
I can also recall at least one instance where the number appears in the films: at the beginning of Generations, Scotty is only able to rescue 47 people from one of the El-Aurian refugee ships.
Why does the number 47 appear so frequently in the The Next Generation?
I am looking primarily for an out-of-universe answer. That is, why were the writers fixated on this number? An in-universe answer would of course be interesting, but I don't expect that such an answer exists.