cannot be sure

USAGE SUMMARY

'cannot be sure' is correct and usable in written English.
You can use it to express uncertainty, doubt, or a lack of certainty. For example: "I cannot be sure what the outcome will be."

✓ Grammatically correct

News & Media

Science

Academia

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

Yet he cannot be sure.

The Economist

We cannot be sure.

The New York Times - Books

But they cannot be sure.

The New York Times - Health

But I cannot be sure.

The Guardian

One cannot be sure about Brecht.

The New Yorker

We cannot be sure until September.

The New York Times

We cannot be sure of Shakespeare's intentions.

The Guardian

Mexico, India or Turkey cannot be sure either.

The Economist

Acordingly, we cannot be sure that the accuracy of current measurements is sufficient.

Advances in Space Research

You cannot be sure when and where they occur.

Cornell University

In fact, he cannot be sure if he is alive.

The New York Times

Expert writing Tips

Best practice

Use "cannot be sure" to express uncertainty when you lack sufficient information or evidence to make a definitive statement.

Common error

Avoid using "cannot be sure" when the situation implies a higher degree of certainty. Instead, consider using softer language like "likely" or "probably" if the available evidence suggests a particular outcome.

Linguistic Context

The phrase "cannot be sure" functions as an epistemic expression, indicating a lack of certainty or definitive knowledge. Ludwig provides numerous examples across diverse contexts where this phrase is used to express doubt or uncertainty about a particular outcome, fact, or situation.

Expression frequency: Very common

Frequent in

News & Media

39%

Science

34%

Academia

8%

Less common in

Wiki

3%

Formal & Business

0%

Encyclopedias

0%

Ludwig's WRAP-UP

In summary, "cannot be sure" is a versatile and frequently used phrase for expressing uncertainty or a lack of definitive knowledge. Ludwig AI confirms its grammatical correctness and usability across diverse contexts, from news and media to scientific research. The phrase functions primarily to qualify statements and acknowledge the limits of certainty. While it is appropriate for both formal and informal communication, alternative phrasings may be considered for stylistic variation. With an expert rating of 4.5, "cannot be sure" stands as a reliable and effective means of conveying doubt in written and spoken English.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

it's uncertain

A shorter, more direct way of stating uncertainty.

it's not definite

Simpler phrasing indicating a lack of certainty.

impossible to know for certain

Highlights the impossibility of achieving certainty; slightly stronger.

it's hard to say

Suggests uncertainty due to difficulty in assessing the situation.

one cannot say definitively

Uses more formal language to express the inability to make a conclusive statement.

unable to ascertain

Emphasizes the inability to find something out for certain; more formal.

we have no way of knowing

Highlights the absence of a method or means to gain knowledge.

we can only speculate

Emphasizes that any conclusion is based on guesswork rather than solid evidence.

it remains to be seen

Indicates that the outcome is still unknown and will become clear in the future.

there's no guarantee

Focuses on the absence of a promise or assurance; more informal.

FAQs

How can I use "cannot be sure" in a sentence?

You can use "cannot be sure" to express uncertainty or a lack of definitive knowledge. For example, "I "cannot be sure" what the future holds" or "We "cannot be sure" of the long-term effects".

What phrases are similar in meaning to "cannot be sure"?

Alternatives to "cannot be sure" include phrases like "unable to ascertain", "impossible to know for certain", or "it's uncertain".

Is "cannot be sure" appropriate for formal writing?

"Cannot be sure" is generally acceptable in both formal and informal writing, depending on the context. In very formal contexts, you might opt for a more sophisticated phrasing like "unable to ascertain".

What's the difference between "cannot be sure" and "can't be certain"?

"Cannot be sure" and "can't be certain" are essentially interchangeable. "Can't be certain" is a contraction of "cannot be certain" and carries the same meaning as ""cannot be sure"".