# “Would’ve” for probability

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#### Karar

##### Member
Hi everybody,

Please consider this sentence:
• The police were patrolling the neighborhood yesterday. I’m not certain why; they would have been looking for the bank robbers.
———

I have heard many native speakers use “would have + pp” instead of “could have + pp” to express probability. Is the use of “would have” conveys the exact meaning of “could have” when expressing possibility? I’m quite confused about this point!

Thank you!

• #### thetazuo

##### Senior Member
Hi. In regard to the topic sentence, I'd say this "would have" is assumption/belief use, expressing that the speaker was confident about what the police were doing at that time.
Besides, "would have" denotes "probability" where "could have" expresses "possibility".
Hope this makes sense!

#### se16teddy

##### Senior Member
Present tense of epistemic will/would:
That will be true = it is probable that it is true.
That would be true = I estimate that it is probable that it is true.

Past tense of epistemic will/would:
That will have been true = it is probable that it was true.
That would have been true = I estimate that it is probable that it was true.

Present tense of epistemic can/could:
That can be true = it is possible that it is true. This form is only used in the negative and interrogative.
That could be true = I estimate that it is possible that it is true.

Past tense of epistemic can/could:
That can have been true = it is possible that it was true. This form is only used in the negative and interrogative.
That could have been true = I estimate that it is possible that it was true.

These negative and interrogative forms are possible:
That can't be true = it is not possible that it is true.
Can that be true? = Is it possible that it is true?
That can't have been true = it is not possible that it was true.
Can that have been true? = Is it possible that it was true?

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#### london calling

##### Senior Member
Is there any particular reason you used the contracted form (would've) in the title of the thread?

#### srknpower

##### Senior Member
Present tense of epistemic will/would:
That will be true = it is probable that it is true.
That would be true = I estimate that it is probable that it is true.

Past tense of epistemic will/would:
That will have been true = it is probable that it was true.
That would have been true = I estimate that it is probable that it was true.

Present tense of epistemic can/could:
That can be true = it is possible that it is true. This form is only used in the negative and interrogative.
That would be true = I estimate that it is possible that it is true.

Past tense of epistemic can/could:
That can have been true = it is possible that it was true. This form is only used in the negative and interrogative.
That would have ben true = I estimate that it is possible that it was true.

These negative and interrogative forms are possible:
That can't be true = it is not possible that it is true.
Can that be true? = Is it possible that it is true?
That can't have been true = it is not possible that it was true.
Can that have been true? = Is it possible that it was true?
So, is “That could have been true.” a wrong sentence? OMG

#### se16teddy

##### Senior Member
So, is “That could have been true.” a wrong sentence?
No. I have corrected a couple of mistakes in my chart.

#### taraa

##### Senior Member
No. I have corrected a couple of mistakes in my chart.
What is the difference between "probability" " and "possibility" that it is said in #2?

#### se16teddy

##### Senior Member
Probable - probability > 50%, 60%, 70% etc, depending on the speaker
Possible - probability > 0%

#### PaulQ

##### Senior Member
I agree with se16teddy:
I have heard many native speakers use “would have + pp” instead of “could have + pp” to express probability. Is the use of “would have” conveys the exact meaning of “could have” when expressing possibility? I’m quite confused about this point!
Hi. In regard to the topic sentence, I'd say this "would have" is assumption/belief use, expressing that the speaker was confident about what the police were doing at that time.
Would implies a level of probability but the level of probability implied by "they would have been looking for the bank robbers." depends on the context - it can be understood as "they were, most probably, looking for the bank robbers."

In "The police were patrolling the neighborhood yesterday. I’m not certain why; they would have been looking for the bank robbers." is unnatural and illogical. The speaker says that he is not certain why, and then he adds "they would have been looking for the bank robbers." which seems to indicate that he is reasonably certain as to why the police were in the neighbourhood...

#### taraa

##### Senior Member
Probable - probability > 50%, 60%, 70% etc, depending on the speaker
Possible - probability > 0%
Thank you very much

#### taraa

##### Senior Member
I agree with se16teddy:
Would implies a level of probability but the level of probability implied by "they would have been looking for the bank robbers." depends on the context - it can be understood as "they were, most probably, looking for the bank robbers."

In "The police were patrolling the neighborhood yesterday. I’m not certain why; they would have been looking for the bank robbers." is unnatural and illogical. The speaker says that he is not certain why, and then he adds "they would have been looking for the bank robbers." which seems to indicate that he is reasonably certain as to why the police were in the neighbourhood...
Can you write the sentence as conditional, please?

#### PaulQ

##### Senior Member
Can you write the sentence as conditional, please?
It would probably be better if you wrote it in the conditional - could you do that?

#### Karar

##### Member
I agree with se16teddy:
Would implies a level of probability but the level of probability implied by "they would have been looking for the bank robbers." depends on the context - it can be understood as "they were, most probably, looking for the bank robbers."

In "The police were patrolling the neighborhood yesterday. I’m not certain why; they would have been looking for the bank robbers." is unnatural and illogical. The speaker says that he is not certain why, and then he adds "they would have been looking for the bank robbers." which seems to indicate that he is reasonably certain as to why the police were in the neighbourhood...

Thanks a lot all! That was so helpful!

Hi Paul,

Do you mean when we use “would” or “will” for certainty it should be considered very likely, not as “might” or “may”?

Thanks!

#### PaulQ

##### Senior Member
Yes - you have provided your own answer.

#### Karar

##### Member
Yes - you have provided your own answer.
Ohh so I was contrasting myself when I said “I’m not quite certain” and then I said “they would have been looking for...” hhh!

There is something about probability that I couldn’t find on the internet; I hope if you could help me understand it.

It’s about the use of “can” when expressing a probability. I found only one website they say:

Can is used for something that is generally possible, something we know sometimes happens:
• Prices can be high in London.
Can is not used to talk about specific possibilities:
• He could be on the bus (not: 'can be').
I really couldn’t understand what they mean by general and specific possibilities!

I hope if you can shed some light on this!

Much appreciated!

#### PaulQ

##### Senior Member
I really couldn’t understand what they mean by general and specific possibilities!
No, I do not see the point of distinguishing between "general and specific" - can (and could) can be used in both cases (although "can", in the specific, is rare.)
"Prices can be high in London." is a general statement because if discusses "all prices", i.e. prices "in general/generally"
"He could be on the bus" You are talking specifically about him and about one specific bus. (Obviously "could" is used because anyone "can" (is able to be) on a bus, so, "could" expresses that there is some uncertainty - it is only a possibility that he is on the bus.)

#### Karar

##### Member
No, I do not see the point of distinguishing between "general and specific" - can (and could) can be used in both cases (although "can", in the specific, is rare.)
"Prices can be high in London." is a general statement because if discusses "all prices", i.e. prices "in general/generally"
"He could be on the bus" You are talking specifically about him and about one specific bus. (Obviously "could" is used because anyone "can" (is able to be) on a bus, so, "could" expresses that there is some uncertainty - it is only a possibility that he is on the bus.)

So does it sound unnatural if we say:

1. Prices might/could be high in London.

2. He can be on the bus.

Aslo, would the meaning be different If we used “migh/could” instead of “can” in sentence#1?

Sorry for asking a lot of questions, but I really wanna understand the nuance difference between them!

#### KsSp

##### Senior Member
I'm sorry to interfere, but I had the same question and found the explanation which seemed quite clear to me. It's on the Cambridge Dictionary website.

#### Karar

##### Member
I'm sorry to interfere, but I had the same question and found the explanation which seemed quite clear to me. It's on the Cambridge Dictionary website.

No problem!

Some websites say that there are instances where we can’t use “could” instead of “can” as in this example:

• Prices in London can be high. (Here we can’t use “could” as the teacher one the website say).

I still don’t quite understand exactly in which instances that we can’t use “could” instead of “can”?

#### london calling

##### Senior Member
So does it sound unnatural if we say:

1. Prices might/could be high in London.

2. He can be on the bus.

Aslo, would the meaning be different If we used “migh/could” instead of “can” in sentence#1?

Sorry for asking a lot of questions, but I really wanna understand the nuance difference between them!
'Wanna' is not an English word.

1. is hypothetical. You do not know if prices are high in London.
2. sounds odd. I can think of no situation where I would use it.

#### KsSp

##### Senior Member
No problem!

Some websites say that there are instances where we can’t use “could” instead of “can” as in this example:

• Prices in London can be high. (Here we can’t use “could” as the teacher one the website say).

I still don’t quite understand exactly in which instances that we can’t use “could” instead of “can”?
As I understand it, the key word here is "epistemic" (as se16teddy wrote above).
The first sentence means different things if "can"/"could" are used.
If we say "Prices in London can be high", it means, as PaulQ wrote above, that in this case prices in general are meant. That is, "Prices in London can be high or low depending on several factors...". If we use "can", we imply the same degree of possibility as seen in "Dogs can be black or white" - it's a general statement which does not convey the idea that the dog you are thinking about is either black or white. It's about all dogs in the world.
If we say "Prices in London could be high", it implies a certain degree of probability. I'd expect to see a sentence like "Take as much money as you can when travelling there, as prices in London could be high". Here we refer to a particular period (current time), a situation (economic or whatever) that defines the prices, so we make an attempt to "guess", as if saying "there are facts that make it possible to think that prices could be high right now".
I'm not a native speaker, so I'm sorry if the explanation above is wrong.

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#### Karar

##### Member
'Wanna' is not an English word.

1. is hypothetical. You do not know if prices are high in London.
2. sounds odd. I can think of no situation where I would use it.

Thanks!

Regarding “wanna”, there was already an objection from one member when I used it, but another member showed up and said that the word “wanna” is totally acceptable but it’s just a matter of people’s style.

My question was why we can say “prices can be high in London” but we can’t say “he can be on bus” instead of saying “he could be on bus”

That’s what I can’t really understand. Some say that only in “specific situations” we use “could/might”. They say “can” is only used with “general situations” ... I can’t seem to differentiate between the “general situations” and the “specific situations” .

• Prices can be higher in London. ( they regard this as a general situation).

While

• He could be on the bus. (they regard this as a specific situation, therefore we can’t use “can” here)

I hope if someone can help ! Thanks a lot!

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#### Karar

##### Member
As I understand it, the key word here is "epistemic" (as se16teddy wrote above).
The first sentence means different things if "can"/"could" are used.
If we say "Prices in London can be high", it means, as PaulQ wrote above, that in this case prices in general are meant. That is, "Prices in London can be high or low depending on several factors...". If we use "can", we imply the same degree of possibility as seen in "Dogs can be black or white" - it's a general statement which does not convey the idea that the dog you are thinking about is either black or white. It's about all dogs in the world.
If we say "Prices in London could be high", it implies a certain degree of probability. I'd expect to see a sentence like "Take as much money as you can when travelling there, as prices in London could be high". Here we refer to a particular period (current time), a situation (economic or whatever) that defines the prices, so we make an attempt to "guess", as if saying "there are facts that make it possible to think that prices could be high right now".
I'm not a native speaker, so I'm sorry if the explanation above is wrong.

Thanks a lot! Your explanation provided some clear points about the general situations. Yeah I kinda got it but still not quite sure about the specific situations where it’d seem awkward when we use “can” like in this sentence:

• He could be on bus. (If we say “he can be on bus” then that would sound unnatural) So how can we know that the situation is specific so that we won’t use “can” when expressing a possibility?

#### KsSp

##### Senior Member
Again, as I understand it, we cannot say "He can be on the bus" because it does not make sense.
"A person can use different means of transportation" makes sense, because there is no particular person: this sentence implies only the fact that people have plenty of vehicles to use, and it says nothing about the particular person whose presense is "felt" in "He could be on the bus". I guess "he" makes the difference too, as "He could be on the bus" looks like a reply to "Do you know where he is?".
What I mean is, "He can use a bus or a train to get from A to B" is about a general possibility, whereas "He could be on the bus" refers to the current situation.
That's how I see it (=it does not mean it is so).

#### PaulQ

##### Senior Member
My question was why we can say “prices can be high in London” but we can’t say “he can be on bus” instead of saying “he could be on bus”
You misunderstand. We can say "He can be on the bus." it is simply that the context is uncommon.

A: "We are all going to London. Some of us will go by car, some by train and some on the bus. [points] You four can go on the train, you two can go by car and you three can go on the bus."
B: "What about John? You have not said how John will get to London."
A: "He can be on the bus with the other three."

or
A: "Where do you think John is now?"
B: "He's probably on the bus."
A: "He can't be on the bus, he's got no money."
B: "He can be on the bus... He works for the bus company and travels free."

#### KsSp

##### Senior Member
Actually, for me as a non-native speaker, "He can be on the bus" sounds odd because it means "He has the physical ability of being in a bus", which is kind of weird.

#### JulianStuart

##### Senior Member
Regarding “wanna”, there was already an objection from one member when I used it, but another member showed up and said that the word “wanna” is totally acceptable but it’s just a matter of people’s style.!
It is acceptable in casual speech (because that's often how "want to" sounds, but otherwise, it will depend on the situation. Here is a post from a discussion of wanna in writing, for example.
I think one thing that should be made clear to the learner is that the likes of gonna and wanna are completely different in status from the older contractions such as isn't, doesn't, I've, you're, he's. Those are acceptable at almost any level of writing, whereas gonna and wanna are still strongly unacceptable in any kind of serious writing.

#### PaulQ

##### Senior Member
it means "He has the physical ability of being in a bus",
No. It is a mistake to limit the meaning implied by "can" in this way. (And can includes mental ability and permissive ability -"I can imagine a cat."; "You can go into the exhibition if you pay"; "Can I have another beer?", "Can this be real? It looks like a fake." etc.)

#### KsSp

##### Senior Member
No. It is a mistake to limit the meaning implied by "can" in this way. (And can includes mental ability and permissive ability -"I can imagine a cat."; "You can go into the exhibition if you pay"; "Can I have another beer?", "Can this be real? It looks like a fake." etc.)
Sorry, I did not mean it was the only meaning, just wanted to add that it was the first meaning which came to my mind in that particular context.
Could you please explain whether "the" makes a difference here? In your example #1 in message #25, you say "on the bus". Would "by bus" change the meaning? Perhaps it's the "the" which confuses us (non-natives), because it makes it look as if a particular bus is meant.

#### PaulQ

##### Senior Member
you say "on the bus". Would "by bus" change the meaning?
Of course. On the bus states the place, because (i) on is a preposition of place and the bus is countable.

In this case, and if it were possible, "by bus" would be a prepositional adverbial phrase and "bus" is uncountable. You will note that all countable nouns must be qualified by a determiner, and "bus" is not - it is therefore uncountable - it describes a general means.

"By" in this case is an instrumental preposition - it tells us what means were used to complete the action/verb. However,
B: "He's probably by bus."
A: "He can't be by bus, he's got no money."
B: "He can be by bus."

Are all incorrect and, simply put - garbage. The verb "to be" only takes adjectivals, and is not a dynamic verb, therefore there is no action to complete.

Perhaps it's the "the" which confuses us (non-natives), because it makes it look as if a particular bus is meant.
The confuses many people who have no articles in their language, but I assure you that "the" does not necessarily mean "a specific bus" and that is not its meaning here.

This thread has now drifted too far off topic. I suggest if you have related questions, you start a new thread.

#### KsSp

##### Senior Member
Of course. On the bus states the place, because (i) on is a preposition of place and the bus is countable.

In this case, and if it were possible, "by bus" would be a prepositional adverbial phrase and "bus" is uncountable. You will note that all countable nouns must be qualified by a determiner, and "bus" is not - it is therefore uncountable - it describes a general means.

"By" in this case is an instrumental preposition - it tells us what means were used to complete the action/verb. However,
B: "He's probably by bus."
A: "He can't be by bus, he's got no money."
B: "He can be by bus."

Are all incorrect and, simply put - garbage. The verb "to be" only takes adjectivals, and is not a dynamic verb, therefore there is no action to complete.

The confuses many people who have no articles in their language, but I assure you that "the" does not necessarily mean "a specific bus" and that is not its meaning here.

This thread has now drifted too far off topic. I suggest if you have related questions, you start a new thread.
Thank you for the reply. My message was not clear enough, I was just wondering whether there's any difference between "He can be on the bus" and "You can go by bus" (as in your example), but you are definitely right - this thread is not the place to ask about it, sorry.

#### Karar

##### Member
Much obliged all!

What Paul said that the use of “can” to express possibility for specific situations isn’t wrong but unnatural is quite reassuring. Yes I too feel it’s unnatural but I just was curious about this very point regarding “can”.

In some websites, I find that the using of “might/could have + pp” limited only to express probability in the past. I just found that they can be express a probability even in the present:

• They might have arrived yesterday. (Past)

• They might have arrived by now. (present)

Using “should’ve” is also acceptable as I think for the present situations:

• They should’ve arrived at the airport by now. It’s 8 pm and they told me they would be at the airport by 7 pm.

Please correct me if there is any misconception.

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#### se16teddy

##### Senior Member
This thread has moved on to discuss a range of meanings of modal verbs that are unrelated to the subject of the thread. Each modal has a range of different meanings, and each of those meanings presents difficulties and deserves at least one thread of its own.
In some websites, I find that the using of “might/could have + pp” limited only to express probability in the past. I just found that they can be express a probability even in the present.
All your examples use the same tense as would have been used without a modal.
Fact: They arrived yesterday. ==> Suggestion (with various nuances): They will/would/may/might/must/shall (rare)/should/can't/could have arrived yesterday.
Fact: They have arrived now. Suggestion (with various nuances): They will/would/may/might/must/shall (rare)/should/can't/could have arrived now.
(Modal verbs do not distinguish between simple past and present perfect.)

Fact: They are there now. Suggestion (with various nuances): They will/would/may/might/must/shall (rare)/should/can't/could be there now.

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#### london calling

##### Senior Member
Is there any particular reason you used the contracted form (would've) in the title of the thread?