After an English class on the subjunctives, I am now confused about the usage of "would".

The definition provided for "would":

(expressing the conditional mood) indicating the consequence of an imagined event or situation.

Before the class, I would typically say something like "I'm sure that would happen."

But come to think about it now, how could you be sure if the consequence is imaginary?

My questions are, instead of saying "that would happen" in the sentence, should I use "that will happen"? And is the original sentence grammatical?

Edit: I'm not asking about the general usage of "will" and "would". I guess my question is more about the combination of word "sure" and "would" since the definition confused me in the first place. So I really don't think my question is a duplicate.

  • Everything in the future is imaginary unless you have perfected a temporal flux capacitor. Did you read any of the dozens of identical questions on this site? This link at ELU might help, too. Commented Sep 2, 2016 at 19:39
  • @Will, the oxford dictionary definition that you quote has several examples, all of which have an if clause. Your sentence does not have an if clause. The If clause provides the imagined event or situation. To make a sentence with this meaning of would, you would need to add an if clause "I'm sure that would happen if pigs could fly". With this sentence, you cannot say "I'm sure that will happen if pigs can fly", because pigs can't fly- it's an imaginary situation.
    – JavaLatte
    Commented Sep 3, 2016 at 5:48

3 Answers 3


Ironically, one of the things that makes learning English tense challenging is the fact we have fairly few forms. Also, the question "is this grammatical" is tough to answer for short utterances without context, as we can almost always come up with some scenario when a native speaker might say it and be understood by other native speakers without anyone noticing anything out of place. A better question is "Does this mean what I think it means" and "Is this what native speakers would say."

So with that in mind, let me actually answer the question you asked!

These two sentences are very similar, so it is not surprising that you would be confused. There is a subtle technical distinction, but the more important distinction is a difference in meaning, which I'll get to.

Is This Grammatical

"I'm sure that would happen"

Grammatically this is fine by itself. I would take it to mean someone has asked you what would happen given some specific circumstances, e.g.:

a. "If I ran naked down the street, would someone call the authorities?"

b. "I'm sure that would happen."

"I'm sure that will happen"

Again, grammatically this is fine by itself. To me the most obvious context would be someone is asking you about your prediction of future events. E.g.:

a. "If I run naked down the street, will I be arrested?"

b. "I'm sure that will happen."

Which Should I Use?

or, "What's the difference?"

Technical Difference

I intentionally chose two examples that are very close together to make a point about agreement, not so much between verbs but between speakers: in the first example, person A says "If I RAN down the street". That "ran" is expressing a hypothetical circumstance (I believe it's technically known as "conditional II" because it's using a past tense verb to indicate something counterfactual). So it is only natural that person B would reply treating it as a hypothetical circumstance, too. Person A didn't say he was going to do it, he just wondered what would happen if he did.

In the second example, person A says "If I RUN down the street". This could still be hypothetical; in fact it probably is, since people don't usually run naked down the street. But because it's being phrased as an action that the person is actually contemplating, it seems a little more natural for person B to respond with "will". But note: "I'm sure that would happen" would also be a perfectly appropriate response.

Semantic Difference

In all the examples I used, everyone is still talking about things that haven't happened. By definition, then, these are "imagined events or situations" like it says in your grammar book. The difference is really based on how definite or how likely the imagined events seem to the speakers. Someone who says "I will" is implying that their imagined event is going to become reality, in a way that someone who says "I would" is not.

If you have a more detailed context, we can probably give you more definite advice to distinguish between the two.

For further reading, please see https://en.wikipedia.org/wiki/English_conditional_sentences which discusses a LOT of different possible uses of conditional in English (with sentence patterns).

  • In explaining "I'm sure that would happen," you write: I would take it to mean someone... Then, in explaining "I'm sure that will happen," you write: To me the most obvious context would be... You use would eight times outside of directly quoting the OP! Is my point clear, @Tiercelet ? Commented Sep 2, 2016 at 20:20
  • @P.E.Dant ...as does OP, when he says "Before the class, I would typically say..." He clearly knows what the form means and wants refinement in when to use it.
    – Tiercelet
    Commented Sep 2, 2016 at 20:26
  • The OP is not the only reader. There will and would be many others in the future, and the imaginary consequences of so many woulds will be, well, consequential. I've answered a couple of these recently, and always strive to banish all forms of the verb under discussion for that reason. It's worth considering, isn't it? Commented Sep 2, 2016 at 20:30
  • Surely there shall be further viewers. However, it is instructive to see language used in comprehensible context. After all, people don't learn from being isolated from all possible examples of what they're studying. If anything, OP's problem is seeing too many explanations and not enough examples.
    – Tiercelet
    Commented Sep 2, 2016 at 20:40
  • The will-would theme is a constant. See this or this for instance. We need a similar tag here (he said to himself...) Commented Sep 2, 2016 at 21:43

In the phrase "I'm sure that would happen", 'would' is an auxiliary verb supporting 'happen', and does not convey the subjunctive tense. In fact, I can't think of any instances of the word 'would' creating a subjunctive clause just because it refers to a future uncertainty; the past subjunctive 'were' is much more common.

In this case, if you were to say, "If this were a perfect world, I'm sure that would happen", the word 'were' forms the subjunctive clause, and 'would' is still a supporting verb. The words 'would', 'could' and 'should' support the idea of causal uncertainty, but do not by themselves create subjunctive clauses.


It says you're from the USA, so I presume English is your first language as it is for me; however, this always cracks me up when native speakers get confused after having a class on the subjunctive and trying to understand it thence. The problem is that everyone and his brother know that we, native English speakers, hate the subjunctive. The subjunctive be damned! The Devil take the subjunctive! The mere mention of the word "subjunctive" is cacophonous to our very ears! We have done such a meticulous job of trying to rid ourselves of the subjunctive that when it dare rear its ugly head, we turn a blind eye and say, "That's not the subjunctive; that's the conditional or the irrealis or the simple past tense" or, my favorite, "That's just a bare infinitive with a missing modal." Yeah, that's like trying to still say this is not your kid after Maury Povich has revealed the DNA test on his show proving that you are the father. So, without further ado, I shall divulge to you the real truth:

There is no such thing as the conditional mood; it's made up. That's right. It's as fake as a $3 bill with a portrait of Bill Clinton blowing a whistle. There are only three moods in English: the indicative, imperative ( also called jussive), and the subjunctive. Much of the past subjunctive exists in conditional statements; in fact, they go hand in hand. If something is conditional, it is usually counterfactual or, at the very least, opens up a possibility that may or may not be the case. In older forms of English, one would even see "were" in the apodosis of if-then statements:

"If I were king, it were a fine job!" (i.e. "it would be a fine job")

This has since died off and, in its stead, conditionals have taken over. So to answer your question, yes, "would" is the past subjunctive form of "will" when it is used in conditional statements that are counterfactual. Despite my divulging this little secret to you, just understand that we don't like subjunctives in English and we'll call it anything else so that we not have to acknowledge its existence. Alas, God forbid the subjunctive exist! God damn it to hell!

  • 1
    Unfortunately, your presumption is incorrect. English is not my first language and the truth is I didnt start speaking it until a few years ago. Anyway, thank you for your answer and I like the way you explained it. Commented Oct 18, 2017 at 16:54

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