Why do I instinctively want to use the present tense with a conditional?

My boss is not a native speaker of English, so he often asks me to correct his writing. The problem is, he wants me to explain why I make changes, and doesn't accept "it just sounds better that way" as an answer. Usually, I come up with some likely-sounding nonsense reasoning, but this afternoon, I just couldn't articulate why I corrected his

We might be able to figure this out from the schedules you will send us.

to

We might be able to figure this out from the schedules you send us.

I know that the version with "will" is perfectly understandable, and I don't think it is ungrammatical per se; but it just sounds better without "will", and I'd like to know why.

Edit: the current highest-voted answer answers the question "why did my boss write it with a future tense". I don't care about that. That's not my question. I want to know why the present tense sounds more natural. Is there a "rule" about this? If it's not the subjunctive (since people keep downvoting the answer which says it is), what is it?

Solution 1:

In your sentence as amended, send is without a doubt in the present indicative tense (and it is not a conditional sentence). In English, however, the present tense does rather more than express what’s going on in the present. To talk about something that’s going on right now, we generally use be + the –ing form of the verb which describes the action or state. We use the present tense, on the other hand, to refer to:

(1) a fact that is always or generally true (Water boils at 100 degrees centigrade);

(2) a repeated action (I go to church every Sunday);

(3) an event that occurs at the moment we are speaking (I promise); and

(4) fixed or planned events taking place in the future (My flight leaves early tomorrow morning).

In your example, send could express either (2) or (4), depending on the context. In either case, it is understood that the schedules are or will be sent according to a pre-arranged plan. If that were not to be the case, you would have to say We might be able to figure this out from the schedules you’ll be sending us. Perhaps that was what your boss meant. If so, he was half right, but we express the future by using will + the plain form of the verb only when we are making a prediction or when we are expressing a decision, often made at the time of speaking, about the immediate future. Neither of those cases seems likely given the first half of the sentence.

Solution 2:

In trying to come up with some "reasoning" for your boss, I think you're likely to hit upon either a dead end or a an invented logic that is essentially a red herring. As in many cases, what you're dealing with is simply an arbitrary choice in how the language encodes something which indeed different languages arbitrarily encode in different ways.

English speakers don't tend to use "will" in subordinate clause in this cases (and so to a native English speaker it sounds unnatural to do so) whereas, say, French speakers would have a strong tendency to use a future tense in this case. Another example:

English: As soon as you arrive, I will help you.

French: Dès que vous arriverez, je vous aiderai. (Literally: As soon as you will arrive, I will help you.)

Other languages may encode this differently again. Spanish speakers, for example, would tend to use a present subjunctive in the subordinate clause:

Spanish: En cuanto llegues, te ayudo. ("In as-much you-arrive-SUBJUNCTIVE, you I-help")

So you're trying to come up with some reasoning or logic for the arbitrary choice made in English. Does this mean that French is more or less "logical" to use a future tense? Is English more "logical" to use a simple present tense? Is Spanish more "logical" to use a present subjunctive?

Well, not really. Remember that names such as "present" and "future" are just arbitrary made-up labels. If we label as "present" a form actually used to denote a future action, then that's a fault of our labelling, not the language. Just because we've labelled a particular form as "present" doesn't then magically mean that the language will suddenly obey some expectation implied by our label.

What you're seeing are just arbitrary differences, of which you'll find all sorts of other examples if you cross-compare languages. And while you're struggling to invent some spurious reasoning as to why "will" is not used in future-oriented subordinate clauses in English, your French counterpart will be inventing some spurious reasoning as to why the future tense is absolutely necessary...

Solution 3:

She'll be riding six white horses when she comes.

See Wikipedia on Present Tense

There is a rule, namely

If the future event is in a dependant clause then it's rendered in the present tense.

Your correction 'sounds better' because it obeys this rule of grammar. You can break this rule without loss of sense, but your boss's version is ungrammatical. It's a general fact about dependant clauses that they obey different rules in relation to verbs than apply in main clauses.

I would be interested in counter-examples to this rule, if anyone can come up with one.

First counter examaple (simplified version of @Peter Shor's example below)

There is a good chance that it will rain.

Is this really about a future event, or are we talking about the current forecast? I'm not sure.

Solution 4:

You sometimes do need to use the future tense in dependent clauses.

We need to review the sites you will visit in Venice.
*We need to review the sites you visit in Venice.

But you don't do it if the future is already implied by another verb in the sentence.

Write to me and tell me all about the sites you visit in Venice.
*Write to me and tell me all about the sites you will visit in Venice.

(Actually, the last sentence sounds fine if you will be writing before you visit Venice.)

What I think is going on is that you use the future in the dependent clause only if the action in the dependent clause takes place considerably farther in the future than the action in the main clause. That is, you judge whether the tense in the dependent clause should be the present or the future by looking at the time of action relative to the action in the main clause. Consider:

We will teach you everything you will ever need for your job.
*We will teach you everything you ever need for your job.

Here, you need to put the dependent clause in the future because it takes place in the indefinite future after being taught.

In your sentence,

We might be able to figure this out from the schedules you send us,

the dependent clause clearly has to happen before the action in the main clause. Thus, you cannot put this dependent clause in the future.

For some additional examples, consider the following sentences:

Go to Union Station, figure out which train will leave for New York at 4pm, and watch it to see whether Dr. X boards it.

The verb in first dependent clause (will leave) takes the future, because the train leaves after you find it. The verb in second dependent clause (boards) takes the present and cannot take the future, because he will be boarding it while you're watching it. You could instead say "which train leaves for New York at 4pm", but only because it's a habitual action—a train leaves for New York every day at 4pm. To see this, consider the sentence:

Go to the garage, ask the attendant which car Dr. X will drive to New York, and leave this note on it.

Here, if you said "which car Dr. X drives to New York", you would be implying that he always drives the same car to New York.

You sometimes even have to use the past tense for dependent clauses that are set in the future, if they are in the past relative to the action in the main clause:

Next Tuesday, go to the Grand Hotel, figure out which room Dr. X slept in on Monday night, and ransack its wastebaskets.

Dr. X sleeps before the action in the main clause, so you have to use the past tense.

The first conditional is a special case of this rule

If his train comes on time, we will miss Dr. X at the station.

In a conditional sentence, the dependent clause almost always takes place at the same time or before the action in the main clause, so you cannot use the future in the dependent clause.