The redundant comma?

[bertietheblue]

Why use a comma if the sense is clear without[,] and the comma doesn't in any affect how you read a piece of text (intonation, pauses[,] etc)? I'm asking this because in another thread I've been discussing ', which' non-restrictive relative clauses. If these are unambiguous[,] why do we need a comma? Look at the preceding 'If ...' sentence[,] for example - there's no comma after 'unambiguous'. It mattered before[,] but does it matter now?

[BobK]

Some people and institutions wrongly insist on a comma before 'which', simply because they hold that 'which' should only be used non-restrictively. It's nothing to get upset about, but it explains the angry red line that keeps appearing in WinWord.

b

[bertietheblue]

Some people and institutions wrongly insist on a comma before 'which', simply because they hold that 'which' should only be used non-restrictively. It's nothing to get upset about, but it explains the angry red line that keeps appearing in WinWord.

b

Yeah, I'm aware of that but what I was asking was: why use a comma if the sense is clear without and the comma does not serve any other purpose (eg to modulate speech)? As an example, we learn that non-restrictive relative clauses are always preceded by a comma because otherwise they might be confused for restrictive relative clauses - since both can begin with the 'which' pronoun - and change the sense of a sentence from that intended. However, often with or without a comma there is only one possible sense so why bother? In other words, how far should grammatical prescription guide us in our punctuation?