Here is an excerpt from The Hitchhiker's Guide to the Galaxy:
'He threw away a copy of Joseph and the Amazing Technicolor Dreamcoat , he threw away a copy of Godspell: he wouldn't need them where he was going.'
My understanding is that independent clauses should be separated by a conjunction, a semi-colon, or a full-stop. Therefore, shouldn't this sentence read
'He threw away a copy of Joseph and the Amazing Technicolor Dreamcoat ; he threw away a copy of Godspell: he wouldn't need them where he was going.'
Although I think the second sentence is technically correct, I would say that the first sentence is more natural. If commas and semi-colons can be thought of as cues for how long we should pause when reading a sentence, then the first sentence is a clear winner. So is Douglas Adams breaking a punctuation rule in the interests of readability, or is no rule being broken at all?