Assume vs. Presume
 

Hi, could someone explain to me the difference between "Assume" and "Presume"? Thanks.

To assume something is a total guess. To presume something is to already have an idea of what is expected before assuming.

I have to disagree about "assume" only being used as a total guess. "Since I ordered it three weeks ago, I assumed that I would have it by now," would not be a total guess, but a logical expectation.

This is another pair where I think the only real difference is in the level of formality, and even that is slight and can depend on your tone of voice. Usually when I choose presume over assume, I'm being more formal, or else using it to convey my displeasure or skepticism, or both, because presume sounds a little bit stuffy to me. "I presume you know what you're doing with those explosives, right?" If I were seriously questioning their expertise, I'd use presume, but if I were teasing them, I'd probably use assume.

That said, the two are virtually interchangeable, so whichever one comes out of your mouth will be fine. :)

Thanks for the help, guys.

This, but only because the vast majority of people use them wrongly!

Just to be technical- Assume= to suppose without any proof, mostly because it seems reasonable. 'I met him at a Japanese event so I just assumed he was Japanese'. It's second meaning is to to take something on, such as 'the military has assumed control of the region'.

Presume means to suppose based on probability, eg, when the boat was found wrecked and empty, it was presumed the sailor had drowned. It's quite likely. It's other meaning is to take something for granted. It's presumed that most cyclists have two legs.

You learn something new everyday. Similar to envy and jealousy. Most people consider it interchangeable but there are differences in definition and usage.

I don't think I see the distinction between your examples. There's no more evidence that the sailor has drowned (or is even dead) in your second example than there is to assign nationality in your first. Both conclusions are not unreasonable however, given their circumstances.

In the online dictionaries I've checked, lack of proof is usually specifically mentioned only when presume is used in the legal sense. What I can gather from various online discussions of this is that presume should be used in the absence of proof, with the expectation that proof will be forthcoming, while assume suggests no intention of seeking more proof. I also gather that a lot of people have trouble seeing the difference between the two words (re the taking for granted definition). :)

One tidbit I ran across is that assume is used 10 times more than presume in spoken and written English (there was no attribution, so can't say if it's true :rolleyes: ).

Do you think people in the UK use presume more often, or differently, than Americans do?

Hmm, looking at it, you're right my assume example isn't so good. It would more be something like 'I generally assume that my mother is in whenever I drop round, regardless of the time, or whether or not I call in advance.' I'm attributing a high probability of meeting her for mostly arbitrary reasons.

However, with the missing sailor and a wrecked ship at sea, it would be incredibly odd to conclude that he was, for example, shot rather than drowned, or had run away to live in Guam, prior to concluding that he was dead by drowning, UNLESS there was evidence to that effect- personality, situation etc. One might HOPE he was alive, but still presume he was dead.

Legal and technical language is often vastly different to general use and for reason of being technical, most people don't know it, but it's interesting that it says 'presume' is a conclusion based on evidence not yet consolidated.

Honestly, I don't think British people use assume/presume much different from the USA, which IS why the very first thing I said was that there isn't much difference between the two so you shouldn't sweat it!

I'm not sweating it so much as finding it interesting to look into it more. :) Googling presume vs assume yielded many more discussions that I expected, and long ones at that!