could not know

USAGE SUMMARY

The phrase "could not know" is correct and usable in written English.
It can be used to express a lack of knowledge or awareness about something in the past or present. Example: "At that moment, I could not know the impact my decision would have on my future."

✓ Grammatically correct

News & Media

Academia

Science

Encyclopedias

Wiki

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

The ants could not know.

The New Yorker

But he could not know for sure.

The New York Times

They could not know that because the wiretapping was secret.

The New York Times

"They could not know who this man is".

The New Yorker

He could not know the precise point at which his cousin had fallen from the car.

Harvard University

He could not know when the tanker might have to cast her off.

Harvard University

We will never know what happened, exactly, just as Anna could not know.

The New Yorker

They could not know the drama — or the pain — that was to come.

The New York Times - Sports

"I could not know what kind of a reception would be accorded me".

The New York Times

"I regret that we could not know her more fully as she was in life".

The New York Times

Hence, he could not know for sure that he had been in the Arctic Ocean.

Encyclopedia Britannica

Expert writing Tips

Best practice

When using "could not know", ensure the context clearly indicates why the knowledge was inaccessible. This enhances clarity and avoids ambiguity for the reader.

Common error

Avoid using "could not know" when "did not know" suffices. "Could not know" implies an inherent impossibility of knowing, while "did not know" simply means the information was not possessed.

Linguistic Context

The phrase "could not know" functions as a modal verb phrase expressing a past inability or impossibility of knowing something. As Ludwig AI confirms, it's a grammatically correct and widely used phrase. It indicates a lack of information or awareness that was unavoidable due to circumstances.

Expression frequency: Very common

Frequent in

News & Media

55%

Academia

15%

Science

15%

Less common in

Encyclopedias

5%

Wiki

5%

Formal & Business

5%

Ludwig's WRAP-UP

In summary, "could not know" is a versatile modal verb phrase used to express a past inability to know something, indicating that knowledge was genuinely unattainable at the time. Ludwig AI confirms its grammatical correctness and widespread usage. The phrase appears frequently in news, media, academic, and scientific contexts. While generally neutral in register, it's essential to distinguish its meaning from "did not know", which simply denotes a lack of knowledge without implying impossibility. For alternative expressions, consider using "was unaware", "had no way of knowing", or "couldn't have known", depending on the specific nuance you wish to convey.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

couldn't have known

Implies the knowledge was impossible to possess at that time.

was unaware

Focuses on the lack of awareness at a specific time.

had no way of knowing

Emphasizes the impossibility of obtaining the knowledge.

was unable to ascertain

Highlights the failure to find something out for certain.

could not foresee

Emphasizes the inability to predict a future event.

remained ignorant of

Stresses the continuing lack of knowledge.

failed to recognize

Highlights a failure to identify or understand.

lacked the foresight to predict

Emphasizes a failure to anticipate future events.

was oblivious to

Emphasizes a state of unawareness or inattention.

had no inkling

Focuses on the absence of even a slight suspicion or idea.

FAQs

How can I use "could not know" in a sentence?

Use "could not know" to indicate a genuine inability to have known something at a specific time. For example, "They "could not know" the consequences of their actions at that moment."

What's a more formal alternative to "could not know"?

Consider using "was unaware" or "had no way of knowing" in more formal writing. These alternatives maintain a similar meaning while lending a more sophisticated tone.

What is the difference between "could not know" and "did not know"?

"Could not know" suggests that it was impossible to have the information, while "did not know" simply states a lack of information. For instance, "He "could not know" the truth because it was concealed", versus "He "did not know" the answer to the question".

What phrases are similar to "could not know"?

Synonymous phrases include "was ignorant of", "remained unaware", and "lacked the ability to determine". Each emphasizes a different facet of not knowing.