# Is there any difference in meaning between a that-clause and a to-infinitive-clause?

Is there any difference in meaning between a that-clause and a to-infinitive-clause? For example, can't the following sentence

It is possible for strikes to happen at any time.

be rephrased with

It is possible that strikes will happen at any time.

?

I've been thinking about this since I read "may, might and can" from Michael Swan's Practical English Usage.

Can is not used in affirmative clauses to talk about the chances that something actually will happen or is happening(= 'It is possible that ...'). To express this meaning, we use may/might/could. We can use can to talk about a more general or theoretical kind of possibility(='It is possible to ...'). Compare:

There may/might be a strike next week. (=It is possible that there will be...).

Strikes can happen at any time. (=It is possible for strikes to happen...)

In the description above, there seems to be the assumption that It is possible that ... expresses a possibility of a specific event, while It is possible to ... expresses a theoretical possibility. But I haven't read about such a difference in meaning between a that-clause and a to-infinitive-clause.

• Yes, I detect a very slight difference. The that version contains the plain statement (the portion after the word that), while the for version doesn't. This makes the that version sound more like a factual statement, and the for version sound more contemplative. Mar 21, 2017 at 11:58
• I don't find your second sentence idiomatic. "it is possible that strikes will happen...". We'd say "Strikes can happen at any time". Mar 21, 2017 at 12:02

It is possible for strikes to happen at any time.

It is possible that strikes will happen at any time.

You have picked up on a nuance, but part of the confusion is your unusual usage in the second sentence.

The first sentence talks about the phenomenon of strikes, somewhat in the abstract, and that they can happen at any time. "Any time" describes a characteristic of strikes, a randomness.

The second sentence could theoretically be interpreted that way, but it's the kind of sentence a person would say to become a participant in a conversation by injecting something meaningless.

"It is possible that strikes will happen" implies an expectation of something definite, specific, and relevant to your situation. So one would expect what follows to be somewhat specific, like "It is possible that strikes will happen next week." "At any time" doesn't really add any information of value.

If the point of the statement is that strikes are expected but the timing isn't predictable, a better way to say it would be "It is possible that strikes could happen at any time". The "could" provides the element of unpredictability.

But the basic difference is the first case refers to strikes conceptually while the second case refers to specific strikes.

• For example, the sentence It is a truth universally acknowledged, that a single man in possession of a good fortune must be in want of a wife expresses a "universal truth", which is indefinite, not-specific, and not so relevant to my situation. What is the difference between this and It is possible that strikes will happen?.
– Aki
Mar 22, 2017 at 7:23
• "It is possible for strikes to happen" is somewhat like your example. "Strikes" is used there in the sense of the general phenomenon of strikes. In "that strikes will happen", "will" means that it is definitely going to happen, which implies (or will be interpreted to mean) that you're referring to specific strikes that will be relevant to you. Mar 22, 2017 at 7:48
• But, "will" can also be used to express habits and characteristics as in "accidents will happen". Isn't it possible that "that strikes will happen at any time" implies a general characteristic of strikes throughout the history and in the future.
– Aki
Mar 22, 2017 at 8:10
• You're correct, and that's what I was referring to in the paragraph where I talked about how it could theoretically be interpreted that way. It would be a true statement, but a totally useless one, which is why nobody would formulate a sentence to state that. Mar 22, 2017 at 8:37
• It is useless, because if it is a general characteristic of strikes it is far more than possible. Am I right? If so, it is the adjective "possible" that makes a that-clause expressing a timeless proposition sound odd.
– Aki
Mar 22, 2017 at 9:02

We can cross the river a mile or so upstream.

The river can be crossed a mile or so upstream.

It's possible to cross the river a mile or so upstream.

It is possible for the river to be crossed a mile or so upstream.

It is possible that the river can be crossed a mile or so upstream.

The first four statements express a known fact. We can ford the river a mile or so upstream.

The last sentence, however, is a conjecture. We may or may not be able to cross the river a mile or so upstream.

With it is possible that, the that-clause expresses a statement about the world which may or may not be true. (That's why I find your use of will in the that-clause above not-quite-idiomatic/marginal.)

It is possible that there are tunnel-dwelling pink unicorns somewhere in the universe.

It is possible that I left my phone on the kitchen counter, but I might have dropped it in the parking lot when I was fumbling for my wallet.

• Is It is possible that there will be a strike next week idiomatic?
– Aki
Mar 22, 2017 at 7:25
• There are certainly more idiomatic, less convoluted ways of saying it. There might be a strike next week. In my opinion, "it is possible that there will be..." is marginally idiomatic. It is grammatical, but if I were to rate the statement on its practicality, it would score low. Mar 22, 2017 at 10:37