Is there any difference between "be able to" and "can"?

Question

Hi everyone!Can anyone tell me if there is any difference in meaning between the use of "be able to" and the use of "can" ?For example: In the following pair of sentences it seems that they are similar in meaning:Scientists are able to explore new planets.Scientists can explore new planets.But what about the following pair: Are you able to help me with my homework? (seems to me that this sentence should be used in a situation in which I am not sure that the person I'm addressing has the knowledge to help me ) Can you help me with my homework? (and this one is more likely to be used in a situation in which I know that the person I'm addressing has the knowledge to help me but I'm not sure he is free right now to do so.) Waiting for your enlightening answers

BarbaraPA · Accepted Answer

I really don't see a difference. According to www.m-w.com, the second defintion of can is "be physically or mentally able to." To my thinking, that makes "He can" and "He is able to" completely synonymous.

If you said "Do you have the ability to help me?" (regardless of my desire or availability to do it just then) then certainly that's different than "Can you..." which could include whether I have the time to do it.

I'm sure others will have their own interpretation, but that's my two cents.

Schetin · Answer

Anonymous
Are you able to help me with my homework? (seems to me that this sentence should be used in a situation in which I am not sure that the person I'm addressing has the knowledge to help me )

This would rather be 'Are you capable of helping me with my homework?' I guess.

As for 'able to' this is the way I see it (this is only an opinion): it's good as an equivalent of 'can' in situations where you can't use the latter (in English you can't use two modals in the same predicate, so the second will be substituted by an equivalent, e.g.: He will/should/must be able to help you). Apart from that, when you want to avoid contextual ambiguity of the meaning of 'can' you can use 'able', say: 'They are able to help you, but what makes you think they can?'

2 coins,

Slava

MrPedantic · Answer

1. Are you able to help me with my homework?

2. Can you help me with my homework?

Milky · Answer

Can has three meanings:

I can do it = PERMISSION – human authority / rules and regulations allow me to do it.

I can do it = POSSIBILITY – external circumstances allow me to do it.

I can do it= ABILITY - inherent properties allow me to do it.

(There are times when these meanings overlap.)

So,

Can you help me with my homework?

PERMISSION: will mum, teacher, the examiner allow it?

POSSIBILITY: if you don't have anything else to do.

ABILITY: are you clever enough/have you got knowledge of the subject

................

The thing to ask is whether be able to also have the same meanings:

Are you able to help me with my homework?

PERMISSION: will mum, teacher, the examiner allow it? (Seems to be OK)

POSSIBILITY: if you don't have anything else to do. (Seems to be OK)

ABILITY: are you clever enough/have you got knowledge of the subject? (Seems to be OK)

..........

So, up to now, it seems as if both convey the same meanings.

........

Coates (1983:93) states that in cases of very strong implied actuality (fact), be able to is normally preferred.

EG: "Most people worked harder than me during the University, of course, and when it came to the exams, they were able to draw not just upon two weeks of knowledge. They were able to draw upon three years of knowledge".

.........

Now, why should that be? Does be able to carry less modality, and therefore more sense of actuality, than can in such contexts?

Let's look at this quote from Coates: 2) Be able to is preferred in the present, if actuality is implied: “...and yet you are able to look at the future of it in this very objective way”.

So, as your sentences/questions are in the present form, maybe the to be able to version expresses more of a sense of actuality than it does modality.

Milky · Answer

Fachinetti (2003) says that constructions containing can are far more general and less precise. So, maybe that's why some of us feel that "are you able to help me with my homework" is more precise in asking for assistance, i.e. it is less ambiguous than can. Added to that, is the fact that it generally appears in more polite/formal encounters. Still, the asking for help with homework seems to me to be a question one would ask to a family member or friend, si I wouldn't see the need for a high.formal expresion such as "be able to". Most of the time, I'd expect to hear "can" or "could" among family members and friends and not "able to".

She also claims that can is compatible with subjects that are animate or abstract, where able to is not:

*This is able to be done.

This can be done.

*This fact is able to disprove their hypothesis.

This fact is can disprove their hypothesis.

Milky · Answer

I feel that be able to in your "are you able to help me with my homework" is equivalent to can you manage to. To me, that would be the default reading.

CalifJim · Answer

I think it's worth mentioning in this thread that the following do not mean the same thing.

I ran fast, so I was able to catch the bus.
I ran fast so I could catch the bus.

CJ

Yoong Liat · Answer

CalifJimI think it's worth mentioning in this thread that the following do not mean the same thing.

I ran fast, so I was able to catch the bus.
I ran fast so I could catch the bus.

CJ

Please let me know the difference between the two sentences.

Milky · Answer

<Please let me know the difference between the two sentences.>

If someone was in the position to do something, or managed to do something, we use "was/were able to" instead of "could".

I ran fast, so I was able to catch the bus. (Managed to catch the bus.)
I ran fast so I could catch the bus. (Ran fast in order to catch the bus.)

The be able to example shows result (resultative), but the can one does not.

Yoong Liat · Answer

Hi Milky

Are you saying the following sentence doesn't indicate whether I caught the bus? In other words, whether I caught the bus or not is something the reader of the sentence does not know.

I ran fast so I could catch the bus. (Ran fast in order to catch the bus.)

The be able to example shows result (resultative), but the can one does not.

Is there any difference between "be able to" and "can"?

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