It’s not real … yet.
The use of modals means we’re no longer expressing what is, but what could be, should be, or tends to be. There’s a strong tie between modal verbs and unreal mood. This actually lines up well with how we use will — and, for that matter, be going to (which is the replacement for the defective will); The future is uncertain, and is therefore (for the time being) unreal. We use will or be going to for as long as it’s not a sure thing (as long as it’s in the future), then a present tense once it IS a sure thing (once it becomes the present).
But what about when we ARE certain about the future? Well, in those instances, we use Present Simple or Present Continuous, even though we’re not expressing a present situation. We could say “The train leaves at 6:30 tomorrow,” or “I’m going to meet up with my friends in half an hour.” So when it might as well be a done deal, we don’t use any modals. But if we don’t have complete confidence in the outcome, we’re more likely to use will or be going to (unless we go so far as to doubt the outcome, in which case we use may or might).
Intentions
Will can also be a noun, as in ‘willpower’. Will is determination; it’s having choice and control over your actions; it’s being deliberate in what you do. Will can be a verb as well, though we rarely use it as such these days. Think of “Do as you will.” You might come across this type of usage in 19th-century literature, where it’s used in much the same way as want.
Whether as a noun or as a verb, will is used to express intent.
The same is true for will and be going to as a modal verb. “I will do better next time,” means “I intend to do better next time.” Not a light intention either, but a determined one. “I am determined to do better next time.” Just as can means “be able to” and may means “be allowed to”, will means “be determined to”.
Therefore, future expressions using will or be going to don’t express what is in the future as much as they express our current intentions.
If it acts like a duck…
Will has the same properties as other modals. Let’s get into one of them.
There are three categories of modal verbs (see our earlier post that explains this), and each modal has two or three variations (each in different categories) with different meanings. For example, can can be used to express possibility, permission, or ability. We like to think of it like mind, heart, and body. Will and it’s past* form would also fit into these three categories. They can express intent or expectation (mind), obligation (heart), or habit (body). Respective examples might be “He’ll arrive tomorrow,” “You will clean your room this instant!”, and “She’ll forget, like she always does.”
There are other properties that will shares with other modals, like having defective qualities, taking ‘have’ afterward to place it further in the past, and being the target of backshifting. We won’t get into the details of those now.
The takeaway
When it comes to form, pay attention to how other modal verbs act to better understand how will should be used.
When it comes to meaning, think less about the future implications and more about present intentions or expectations about the future.