David Marsh makes an excellent statement of something I believed when I woke up yesterday morning: restrictive clauses (giving information essential to define the scope of a statement) should begin with ‘that’, while non-restrictive clauses (giving supplementary information) should begin with ‘which’. Thus:
1) The cakes that I baked won first prize. [restrictive: I’m singling out my cakes]
2) The cakes, which I baked, won first prize. [non-restrictive: the only cakes under discussion are mine, and I’m adding my claim to them as an aside]
And the following would be incorrect:
1a) The cakes which I baked won first prize. [supposedly restrictive]
But after reading some interventions from Stan Carey (expanded here), and an Arnold Zwicky post he linked to, I have recanted. Everyone agrees that 1 and 2 are right (everyone also agrees that ‘The cakes, that I baked, won first prize’ would be wrong), but now I agree that 1a is OK too. ‘Which’ and ‘that’ can both work for restrictive clauses.
Linguistic rules (or ‘rules’) may or may not be widely and consistently followed, but even if they’re not, they’re still worth hanging onto if they serve a useful purpose. The that-rule is on the niche side (lots of people, including lots of Respected Writers, ignore it), but I had thought it useful for clarity’s sake.
But it’s not. There’s also a difference in the punctuation of restrictive and non-restrictive clauses. 2 and 1a are clearly distinct in a way that makes it hard to misunderstand: the aside in 2 is marked with commas. This suggests insisting on ‘that’ is unnecessary.
Is it always unnecessary?
David’s strongest counterargument is when we’ve got sentences with more complex structure – particularly with other asides and the extra commas they bring. For instance (my own examples, but based on his point):
Portugal is a nice country, like Spain, which I visited last year. [I visited Spain]
Portugal is a nice country, like Spain, that I visited last year. [I visited Portugal]
Abandoning the that-rule would cost us “a useful distinction here”, David argues.
Not necessarily. There are other ways to show the difference. For one thing, we could repunctuate:
Portugal is a nice country, like Spain (which I visited last year). [I visited Spain]
Portugal is a nice country (like Spain, which I visited last year). [I visited Spain]
Portugal is a nice country (like Spain) which I visited last year. [I visited Portugal]
And there are any number of ways to rephrase for clarity.
But what clinches it for me is that there are times when the that-rule positively leads to calamity (I exaggerate, but I have to maintain a sense of excitement in my life somehow). Some restrictive clauses just don’t work with ‘that’. Arnold offers:
The only case of which I have direct knowledge occurred in 1972.
It has to be this way: ‘The only case of that I have direct knowledge’ is a train wreck.
But could we handle such cases by saying that restrictive clauses should use ‘that’ rather than ‘which’ except when the clause begins with a preposition? Only at the cost of further complicating matters. And at the cost of missing other exceptions – commenting on David’s piece, shemarch offers:
The best use of a word is that which makes the clearest sense.
Another restrictive clause that would be absurd if introduced with a ‘that’ instead of a ‘which’. And I’d not want to rule out other types of counterexample.
The that-rule doesn’t work. And so, yesterday night, I went to bed having gladly renounced it.
(In spite of all this, I still think ‘that’ is usually better aesthetically than ‘which’ for a restrictive clause. Maybe it’s the sharper ‘T’ sound at the end, which gives a better sense of narrowing down or pointing out; maybe it’s association with the demonstrative use of ‘that’, as in ‘Look at that restrictive clause!’ So I’ll mostly stick to ‘that’, but no longer on grammatical grounds.)