At this moment the King, who had been for some time busily writing in his note-book, cackled out `Silence!' and read out from his book, `Rule Forty-two. ALL PERSONS MORE THAN A MILE HIGH TO LEAVE THE COURT.'
Everybody looked at Alice.
`I'm not a mile high,' said Alice.
`You are,' said the King.
`Nearly two miles high,' added the Queen.
`Well, I shan't go, at any rate,' said Alice: `besides, that's not a regular rule: you invented it just now.'
`It's the oldest rule in the book,' said the King.
`Then it ought to be Number One,' said Alice.
Why did Lewis Carroll use the Number forty-two?
Most references, including The Annotated Alice (Martin Gardner) and the Penguin Classics edition (also annotated, to a much lesser extent), discuss various number combinations.
There is, however, another factor which could have influenced the choice of using a ‘Rule Forty-two’ based on Christ Church, Oxford.
The College’s head was (and still is) the Cathedral’s dean (a senior clergyman at the Cathedral). Also, during Dodgson's time there, its lecturers had to ordained Anglican clergymen to teach there.
It was also established at the time of King Henry VIII‘s break from the Roman Catholic Church (1533). His new “English Catholic” Church (‘Anglo-Catholic’ or ‘Anglican’) eventually had the “The Thirty-nine Articles of Faith” created to govern its beliefs.
Thirty-nine Articles of Faith
https://en.wikipedia.org/wiki/Thirty-nine_Articles
During the short reign of Edward VI (1547-1553), this was increased to Forty-two Articles, to make it similar to the Protestant Churches (e.g. Calvinist and Lutheran). With people of the more Protestant or "Puritan" beliefs no doubt regarding the new ones as being more important...
When Elizabeth I became Queen (in 1558) the later additions were removed, returning the number back to the original Thirty-nine Articles.
So, an additional aspect of this passage could be regarded as Dodgson satirising people who insist on minor additions, or later rules are more "important" than the founding major principles / rules.
It could just be a coincidence though.
