The words presume and assume are very similar in meaning and are often used interchangeably. However, there is a clear difference in meaning that you should know about if you want to make accurate word choices.
Here we’ll look at when to use presume vs assume, including plenty of example sentences to help you understand the difference and how to avoid mixing these words up.
What’s the difference between assume and presume?
The verbs presume and assume both mean to suppose or to take something as true. The difference in meaning lies in the degree of certainty of the person making the claim, or the amount of information available to make the deduction.
- When you presume something, you have some evidence to support the reasoning or there is a strong probability that it is true.
- When you assume something, there is little or no evidence to support the reasoning and there is a smaller chance of it being true.
Because this is such a subtle difference, people often end up using the words interchangeably.
Both verbs do have additional meanings, but these are quite distinct from each other and easier to distinguish between. For now, we will focus on the definitions above which are the most easily confused.
Example sentences using presume and assume
Let’s look first at some example sentences using ‘presume’. In these, the person is drawing a conclusion based on logical reasoning or substantial evidence.
- Two skiers are presumed dead after being hit by an avalanche yesterday.
- I presume Melanie will be attending today’s meeting, since she has been present at every one so far this year.
- I presume that man is the team coach, as he is the only one not wearing a uniform.
- Based on your resume, we could only presume that you have no relevant experience.
- I presume your girlfriend is here, since her car is in the driveway.
You’ll notice that many of these sentences use reasoning transition markers like ‘since’ and ‘based on’, as these help us link the conclusion with the reasoning behind it.
Now, we can compare these with some example sentences using ‘assume’. Here you will see that there is more guesswork involved, and no real supporting evidence:
- For the purposes of this study, I have assumed that prices will rise by 10% annually.
- We all assumed that James would come to the party although nobody actually asked him.
- I wrongly assumed that my dinner guests didn’t have any allergies.
- I didn’t check if I had enough money to pay; I just assumed I did.
- He hasn’t replied to my messages all day so I can only assume he is mad at me.
- I assumed that this promotion would come with a substantial pay increase.
As you can see, we often use ‘assume’ when we are reflecting back on something we thought to be true that turned out to be false.
Both ‘presume’ and ‘assume’ are synonymous with the word ‘infer’, which is often confused with ‘imply’. Read about infer vs imply for more information.
As nouns: Presumption vs assumption
The noun forms of presume and assume – presumption and assumption – have the same difference in meaning.
An assumption is a guess or a deduction made with little confidence.
A presumption is a deduction made with a greater degree of confidence, especially if evidence-based. This could also be called an educated guess.
Presume vs assume vs suppose
The verb ‘suppose‘ is a synonym for both presume and assume. It does not have the same implication of certainty or uncertainty, so it can be a good substitute in cases when you’re unsure whether to use presume or assume.
The noun form, supposition, is also valid but less commonly used.
In more casual speech and writing, you’ll hear people use the verb ‘guess‘ as another synonym for these three words, as in “I guess he isn’t coming after all.”
Conclusion: Assume vs presume
We hope this has helped you to understand the subtle difference between assume and presume.
Since these two verbs are very similar in meaning, choosing the wrong one is not really going to cause any big misunderstanding. This is similar to other commonly confused words like attain vs obtain and lay vs lie.
It’s only if you’re speaking in a formal context or creating a piece of writing where the meaning really makes a difference that you should agonize over the correct choice between presume vs assume.
