[Vocabulary] What/which matters most

[nyggus]

Hello,

Do the following sentence differ in meaning (or anything else)?

1. Among the things I'm working on, what matters most?

2. Among the things I'm working on, which matters most?

Thanks,
nyggus

 

[Skrej]

I see no discernible difference between them.

 

[emsr2d2]

I'd be inclined to use "which" because you're offering options. If the listener is expected to choose just one of the things the speaker is working on (the use of the word "most" suggests that that is the case), you would need to be able to add the word "one" to the end of the question and that only works in the second.

Among the things I'm working on, which one matters most? :tick:
Among the things I'm working on, what one matters most? :cross:

Note that I would find it more natural to start with "Of the things ...".

 

[nyggus]

Thanks. I took the second sentence,

Among the things I'm working on, what matters most?​

from Roy Peter Clark's "HELP! for Writers". I am sure he chose the wording on purpose, but I've always felt which sounds better in such constructions and should be preferred. Now, seeing that it was R.P. Clark who chose what...