Learn English – “Don’t mind what she does tomorrow” but not “Don’t know what she does tomorrow” Why

grammaticalitymodal-verbsquestionssyntactic-analysis

Bounty note:

This question is primarily about the acceptability of will in different types of environment. I have used the verb mind in my examples, but if you are an American English speaker, as opposed to a UK one, you might like to substitute this with the verb care (it doesn't make any difference to the question).

The question

Let's suppose that Maria the elephant is going to take part in a performance tomorrow. I am discussing potential acts for her, and my friend responds:

  1. I don't mind what she does tomorrow.

Now that subordinate clause what she does tomorrow uses a present simple construction. If he'd said:

  1. I don't mind what she will do tomorrow.

That would have been passable, but feels a bit wonky for this particular conversation. Here the subordinate clause uses the modal verb will (in what's often called a future simple construction) instead of the present simple.

Now, my friend could easily have said:

  1. I don't know what she will do tomorrow.

Here the future simple seems perfectly apposite. However this time, in contrast to the examples in (1-2), the present simple sounds positively wrong for this conversation:

  1. *I don't know what she does tomorrow.

Ok, so far so bad. However, if we deconstruct the differences in meaning between the two sentences, things become yet more confusing. Here's why. Remember that I was discussing Maria's potential act tomorrow, which means that what act she's actually going to perform is completely undecided. Now if we consider this against sentences (1-2), this seems to be part of the problem with sentence (2):

  1. I don't mind what she does tomorrow.
  2. I don't mind what she will do tomorrow.

It seems, to me at least, that sentence (2) would be perfectly fine if what Maria was going to do had already been decided, but is wonky because nobody, including Maria, knows what she's going to do. So the will here would be ok if what she was going to do tomorrow was already known.

We can compare this with (3-4):

  1. I don't know what she will do tomorrow.
  2. I don't know what she does tomorrow.

Here the version with will is fine whether or not we know what Maria's going to do. In contrast, (4) can only be used in some kind of other situation in which what Maria does has already been time-tabled. So if she does the cha-cha on Tuesdays and the high trapeze every Wednesday and so forth, for example, but the speaker cannot remember which specific thing Maria does on a Thursday—and today is Thursday—then sentence (4) is perfectly appropriate.

So my questions are:

  • Why does "will" sound wrong in the first pair of examples , and why does not using "will" sound wrong in the second pair? (given the situation described).

  • What is it about the verbs mind and know (or care and know) that causes this difference?

Best Answer

The major difference between the predicates distinguished here with Wh-clause complements is that

  • not know belongs to a class of predicates that takes a Disjunctive Wh-clause complement

whereas

  • not care (in the US) belongs to a class that takes a Conjunctive Wh-clause complement.

The difference is in the pragmatic nature of the Wh-clause; conjunctive clauses are factive --
they presuppose the identity and truth of their complement. E.g,

  • I am aware of/They'll be surprised by/He doesn't care what she does tomorrow.
    In this example, the clause refers to the set of all actions that she is to do tomorrow,
    as a settled matter; it's called conjunctive because the set consists of A and B and C and ...

while disjunctive clauses are indefinite, and presuppose nothing, E.g,

  • It's a mystery/I wonder/They don't know what she'll do tomorrow.
    In this example, the clause refers to an unknown set of possible events or actions;
    it's called disjunctive because the set consists of A or B or C or ...

Since the conjunctive clause is presupposed, there's no need for a predictive modal like will. But the disjunctive clause is indefinite, and its truth set may be empty ("..., if anything"), so the predictive will is necessary.