Skip to content

Should You Use Assume Or Presume?

Although presume and assume are used almost interchangeably in the English language, there is some distinction between them that separates their meanings. In general, both terms mean “to take something as true or real.” However, the difference lies in the level of confidence each word gives the user. In most cases, presume is used to show that the writer has high confidence in his presumption or that they are using evidence/context to guess. In contrast, assume is usually used to show that a guess is being made with little or no evidence to back it up.

To sum up these differences:

  • PRESUME implies more confidence/evidence to support a claim
  • ASSUME applies that a guess is being made with little evidence/confidence.

Graphic illustrating the difference between assume or presume. Presume implies more confidence or evidence to support a claim, whereas assume implies that a guess is being made with little evidence or confidence. Summarizing the Main Difference

The degree of confidence or certainty in your presumption or the level of evidence to back up your supposition are the most important difference between the two. The verb assume implies that you are less confident and have minimal evidence to back up your claim. Meanwhile, the verb presume implies a higher level of confidence and evidence.

An Analogy to Think of the Different Usages

An analogy can help illustrate the slight difference between assume and presume. You can think of the difference between these two terms as similar to the differences between brother and sister. They have nearly identical meanings but slightly different use cases. In the case of brother and sister, the difference in use depends on gender. For presume versus assume, the difference is your certainty.

Graphic illustrating the difference between assume and presume.

Origination of Assume and Presume: A Shared Etymology

According to one of the first distinctions of these words in Webster’s dictionary, 1828 was most likely when these two words were first distinguished from each other. In this distinction, it was noted that assume should refer to situations with little proof, while presume should be used to refer to situations with some examination or positive proof. In their very basic roots, these terms come from the Latin word sumere, which means “to take.” They later split when the prefix pre/prae- was added to presume, and the prefix ad/as- was added to assume. 

To show the difference in these words, the current meaning of presume is “to assume especially with confidence,” which shows that these terms have become interchangeable in modern English.

Example Sentences Using Presume and Assume

A biologist may assume that all complex creatures have evolved from simpler ancestors.

Most people accept that buying brown sugar often costs more than regular sugar. They normally assume that brown sugar is created through extra processes/special materials, logically meaning that it should cost more. 

When I saw wrappers all over the floor, I assumed that the dog had gotten into the Halloween candy.

Because you don’t have your homework with you, I presume that you didn’t do it. 

The textbook should be available to everyone, presuming that everyone can access the school computers. 

A Note on the Examples and These Confused Words

All of the above example sentences use each verb in its official definition. That said, if you were to use presume where assume is an example or vice versa, you would be understood. Few people police usage of these terms. Keep that in mind and be willing to take an educated guess if you aren’t sure which word to use.

Of course, you can guide children as young as they are if you want them to be confident in the difference between the two and the proper use of each word.

Law: Where Presumption, Not Assumption Is the Right Choice

While most use cases let you use presume and assume interchangeably, the law is a notable exception. You will likely hear the phrase “presumption of innocence.” This refers to the fact that the burden of proof is on the prosecution, and someone is considered innocent until there is reasonable evidence showing they are not.

Assume is not used in this context, at least not officially.

An interesting note is that this situation also slightly changes the definition of presume. Remember that normally, using the term presume implies you are very confident or have evidence. But in this legal situation, presumption of innocence means that someone is supposed to be innocent but there is no proof.

Using Assume and Presume: Which Is the Right Word?

Although both terms have now become interchangeable in our language, some people still recognize the small distinction between the two. If you want to show that you have more confidence in your inference, you should probably use presume. If you are more unsure about your claims, assume is probably the best bet. If you aren’t worried about using them for distinct situations, most people get by with picking whichever sounds best and using it.

Examples From the Media

Let’s take a look how the words are used by various literary sources:

The Guardian:

“I can only assume it’s a mistake,” George said, when asked why flights to Queensland were approved as expenses to be charged to Sydney Water.

The Guardian:

The committee chairman agreed – that there was a link between miasma and fever – but would only go so far as to say: “I should presume that over-crowded burying-grounds would supply such effluvia most abundantly.”

Related: For more articles about similar words, click here!

Posted by Avatar photo
By Ryan Fisher

Ryan holds degrees from Pacific Lutheran University and specializes in proofreading, editing, and content writing with an emphasis on business communication.

Leave a Reply

Your email address will not be published. Required fields are marked *