"Do you think he can still be alive?", "Can" used for probability, or what?



I came across these sentences in a learner's dictionary (see examples for sense 3a) today:

Do you think he can still be alive? [= do you think it is possible that he is still alive.]

I don't think he can still be alive. [= I think he must be dead.]

Since the second one is negative, it's probably not wrong, as it's pretty much a paraphrase of I think he can't still be alive. and can't can be used with the sense of 0% probability, i.e. can't = I'm certain it's not true.

The Problem

From what I've known and what I've read, could, but not can, is usually used this way to indicate probability either in the present or the future, as in he coud be in the garden.

As for possibility, can can only be used to tell general possibilities/truths (It can be rainy here during September.) or the possibility in a particular situation (We can go to Paris this weekend, since we don't have to work).

What I Think & What I've Tried Doing

I think the first one should read

Do you think he could still be alive?

and probably even the second one should read

I don't think he could still be alive.

However, it seemed strange to me (who is a non-native) when I replaced could with may in the first sentence, which is usually possible when talking about probability.

*Do you think he may still be alive?

I also noticed that

Do you think he is still alive?

seemed more natural.

The Questions

  • What is can doing there?
  • In what context is can used like this?
  • Can could do the job too?


  • I'm talking about using can and could in the present here. (This may lead to varying answers if I don't make this clear, I think)

  • Please, please avoid the word "possible" where possible. If you're going to use it, please make it clear what kind of "possible" you mean: generally possible (he can be hard at times), possible in the situation (we can go to Paris this weekend because we don't have to work), possible as in probability (he could be in the car.)


Posted 2014-04-08T16:17:10.073


If it's Merriam Webster and saying that can can be used that way, why don't we accept it? In fact, seeing this I learned that okay, it can be used this way as well! – Maulik V – 2014-04-08T16:26:07.777

1This has nothing to do with me accepting the use. I certainly accept the use. The question is about how and when to use it this way, and why they use it that way. – None – 2014-04-08T16:26:36.093

1I just got an idea a moment ago: can is used in the examples to state the possibility (as in speculation). Unlike in another example, "Where’s my bag? Have you seen it? – No, but it ?can be in the car.", this can is possible because of the speculation is evidence-based (external). Also, interrogation and negation might be related to the possibility of the use of can in the example sentences. In this context, could would also work. – Damkerng T. – 2014-04-08T19:04:19.860

I like the point that interrogation and negation might be related to the possibility of using can (as they are usually grouped together in grammar). I however still think that in your example could (or may, or might) can only be in that place. This is just me though. I haven't gone to bed after all... – None – 2014-04-08T19:23:43.573

I think "I think he could still be alive" is more natural. Perhaps they were trying to keep it simple and only explain one thing at a time? – starsplusplus – 2014-04-28T08:08:59.387

@DamkerngT. I don't think you could say "it can be in the car". Unfortunately I'm not sure why; it just sounds wrong. However, the "could" in my first sentence can be replaced by "can" and the first "can" in this sentence could be replaced by "could". ;) – starsplusplus – 2014-04-28T08:11:02.023

@starplusplus I wrote that comment before I learned how to write a star (*) in a comment. I wanted to type "No, but it *can be in the car." (with a star indicating an incorrect usage) but I couldn't, so I typed "No, but it ?can be in the car/" instead. (I told the OP about that in a chat already.) Thanks for the comment anyway. ;-) – Damkerng T. – 2014-04-28T08:22:11.057



This sense of can is what linguists call a negative polarity item (NPI). You're already aware that can't can be used to mean "is not possible", and you clearly have little difficulty accepting that can can be used to mean "is possible" when the context effectively negates it ("I don't think that …"). So the tricky part is just recognizing that in English, negative polarity items are also licensed by (i.e., allowed to occur in the context of) questions.

Another negative polarity item is any; as you can see from these examples, they have similar distributions:

  • Direct negation:
    • 1 isn't greater than any other positive integers.
    • 2 can't be greater than 3.
  • Negation in a matrix (containing) clause:
    • I don't think 1 is greater than any other positive integers.
    • I don't think that 2 can be greater than 3.
  • A question:
    • Is 1 greater than any other positive integers?
    • Can 2 be greater than 3?
  • Use after only:
    • Only 1 is greater than any other positive integers. [This is false, of course, but the statement is grammatical.]
    • Only 2 can be greater than 3. [Ditto.]

Note that not all NPIs are licensed by the exact same contexts: some require more thoroughly negative contexts than others. Also, a word can be an NPI in one dialect, or in one register, without being an NPI in a different dialect or register. So this is a rough observation, rather than an firm guarantee of identical behavior. But it's a good first approximation.


Posted 2014-04-08T16:17:10.073

Reputation: 4 098


I'm wondering whether this is a regional variation. The sentence

*Do you think he can still be alive?

sounds somewhat strange to me. Instead, I would say

Do you think he might still be alive?

Do you think he may still be alive?

Do you think he is still alive?

The problem seems to be that "to be alive" is not an action but a state. That's why

Do you think he can still swim?

Do you think he can still go out with his friends?

Do you think he can still trick his wife?

are all okay. But the following sentences seem odd:

*Do you think he can be an American?

*Do you think he can be sick?

*Do you think he can have a green car?


Posted 2014-04-08T16:17:10.073

Reputation: 1 130

Could you maybe edit this to highlight the distinction you're making between "can [be state]" and "can [do action]"? I missed the importance on first read and that's why I'm only now +1ing. – starsplusplus – 2014-04-28T10:48:46.423


Yes you are definitely right. Some things in english literature is not what it is supposed to be. There are words like "barely possible", "full empty", etc which has different meaning but we can generally understand it. The word "can" in the sentence

A :- “Do you think John can still be alive?" B :- "Yes i think so"

means probability but in a negative sense. A thinks John is dead so he is asking for B's opinion


Posted 2014-04-08T16:17:10.073

Reputation: 111


In questions we can use "can", (to talk about general or specific possibility" , "could", OR "might". We do not use may. e.g. "I got a bouquet of flowers, but there was no card." "Who can/could/might they be from?' " Do you think they can/could/might be from Frank?" "Do you think that Frank can/could/ might still be alive?"


Posted 2014-04-08T16:17:10.073

Reputation: 3 562


I agree with your thinking. In my opinion, the examples given are poor.

I don't think he can still be alive.

reads much better as

I don't think he could still be alive.

The problem is that this sense of can is usually reserved for ability or action, whereas being alive is a state. See dynamic verb (for ability and action) and stative verb (for state).

Compare with

I don't think he can drive.

This sounds much more natural because driving is an ability, not a state.


I don't think he can be good.

Here, "be good" is describing behaviour, therefore an action, whereas "be alive" or "be hungry" are states. It's possible to say "He is being good", whereas *"He is being alive" and *"He is being hungry" are ungrammatical.

The examples on the Learner's Dictionary are not totally incorrect, but are unlikely to be found in most situations.

CJ Dennis

Posted 2014-04-08T16:17:10.073

Reputation: 3 832


Both could and can can be used, but the connotations are a little different.

Do you think he could still be alive?

Could refers to probability or likelihood; "How likely is it that he is still alive?".

Do you think he can still be alive?

Can refers to possibility, the ability to be alive; "Is it possible that he is still alive?".


Posted 2014-04-08T16:17:10.073

Reputation: 5 349


We cannot argue that can can be used that way -the dictionary says. But if you are asking why, I can not explain like a grammarian can. However, I can surely put this it in better way that with negation or in question one use of can is to express doubt of something/someone. I'm just trying to help you.

can (v) (#1.3) - (with negative or in questions) Used to express doubt or surprise about the possibility of

I think it fits to your concern.

Maulik V

Posted 2014-04-08T16:17:10.073

Reputation: 66 188