Can for future possibility

Question

I'm doing a research on English modality (for reference I'm using F.R. Palmer's book "Modality and the English Modals").

In the book the author distinguishes between the three kinds of modality his model posits:

• Epistemic modality (for possibility)

• Deontic (for permission and obligation)

• Dynamic (subject oriented "modality" i.e. objective potential)

To test the practical application of the theoretical points given in this book, I turn to native speakers' aid, but the issue is that everyone appears to have their own interpretations of modality in what seems to be the same context (some might understand a modal to be deontic (e.g. you have my permission to do that), while others understand it as dynamic (there is an objective possibility to do that).

To have a better understanding of what I mean, please, take a look at my thread on wordreference.com (particularly at the post #8, where I give a link to yet another one of my posts).

https://forum.wordreference.com/threads/can-will-be-able-to.3627055/

Only few people accepted the use of "can" there, but here (#1, Ex. 4) a similar example was validated:

https://forum.wordreference.com/threads/can-or-be-able-to-in-the-future.3626301/#post-1847635

There seems to be some misconception at play. This might be due to the fact that when we acquire language as children, we absorb it intuitively with no instructions. The language doesn't come in a package together with a user guide like a table from IKEA or some exhaustive grammar book explaining how our mind generates grammar. There's nothing to language but the language, so oftentimes we have to base our inferences on intuition. My objective here is to understand whether "can" is indeed not used to denote objective future possiby or is it just that the native speakers preceive "can" in my examples to be something else (e.g. permission or epistemic possibility).

Could you, please, check if my assumptions about the meaning of "can" in the following sentences are correct. If they are not, how would you interpret them?

Ex.1

A: What is this bank good for?! We all are jobless!

B: When Barclays opens a branch in our town, you [can / will be able to] apply for a job there ("B" merely states a fact about future possibility; "to be able to" is more naural here).

Ex.2

A: I need to find a job.

B: When Barclays opens a branch in our town, you can apply for a job there ("B" suggests a solution; in such situations "can" looks better. In the book this use of "can" is titled as "implication").

Thank you in advance!

Answer 1

I think you have opened a 'Can' of worms here! (Sorry for the idiomatic reference). To answer your edit, "To be able to..." is used in more formal environments, whereas "Can", tends to be the more informal alternative. For example, I would use:

If doctor to patient: "Are you able to bend your knees?"

If mother to child (or perhaps nurse to patient): "Can you bend you knees for me?"

Can is a very complicated subject.

If Barclays [or any other bank for that matter] opens a branch "you can apply for a job there [if you want to... / you have the ability] The writer is suggesting that, in my opinion, you have the ability (permissive in this sense).

It could also be used informally / scoffingly in the negative: "You can apply for a job there if you want to!... With the subtext: But I would not [because its a terrible job!]"

From an information presentation style, I would normally put the pre-condition [When Barclays, open a branch] first, because the action [applying for the job] is conditional on this having happened first. If Barclays change their mind and don't open the branch, THEN you may not want, or be able to apply for a job elsewhere - at another branch. Therefore the permission is not required.

Equally, "If Barclays opens a branch in your town" - albeit highly unlikely in the present economic climate - it is also possible that you cannot [or can't] apply for a job there [because they are fully staffed / you are not qualified / you are only 6-years old...]

Answer 2

To be honest, I don't think native speakers here can give you the answers you want. They tend to randomly agree with or disagree with something with no reasons, which cause your confusion. Another fact is that they might keep asking for more context while ignoring the fact that you are just looking for a clear cut answer.

Anyway, here's my thought about when to use can and will be able to

When both "can" and "will be able to" are acceptable

1. Suggestion (can+things you suggest someone should do & can+ things you suggest someone should do to achieve)

e.g. a. If you find him a car, he can drive you back.
b. If you feel tired, you can go to bed now.

3. Availability
4. Permission
5. Immediate possibility
6. Offer
7. Schedule

When only "will be able to" is acceptable

1. Gaining an ability that the person currently doesn't have
2. Negative (will be able to should be sued instead of "can't")
3. Long-term activity (speak English, swim, play soccer, etc)

These are the general rules that I see. Maybe native speakers might not admit it but these rules do exist and they follow them on a daily basis.

Hope this helps.