Presume/Assume

Scarinae

What is the difference between the two words? When do you assume something to be the case, and when do you presume it to be the case? I'm sure there must be a difference but I can't work out what it is

Talliesin

Strictly (and ignoring other definitions irrelevant to the question) one presumes when one acts upon what one believes, though without full evidence to support it, and one assumes when one acts upon what one believes to be possibly true.

presume - belief
assume - hypothesis

However the use of the word "assume" has moved towards the meaning of presume.

Eoin

Talliesin wrote:

Strictly (and ignoring other definitions irrelevant to the question) one presumes when one acts upon what one believes, though without full evidence to support it, and one assumes when one acts upon what one believes to be possibly true.

presume - belief
assume - hypothesis

However the use of the word "assume" has moved towards the meaning of presume.

Was actually going to post this question myself...

Dictionary.com has these two definitions (again, ignoring irrelevant definitions):

Assume:
To take for granted; suppose:

Presume:
To take for granted as being true in the absence of proof to the contrary: We presumed she was innocent.

Still a bit confused actually

po0k

Does either imply prior knowledge or experience of the subject?

Tar.Aldarion

i would hazard presume moreso than assume,as in,you assume-take it for granted and presume-take it for granted because you think you know something about it due to experience or prior knowledge.It's really hard to infer from the various definitions though...

Eoin

SyxPak wrote:

Does either imply prior knowledge or experience of the subject?

I assume/presume one of them does

Scarinae

So if you're being presumptuous, does that mean you are actually basing your conclusions on something?

Talliesin

Both are taking something for granted, but originally you'd be open to correction with an assumption - but acting as if your assumption was correct in the meantime (perhaps with a view to testing it to see if it was true).

In most modern use the two are pretty much synonymous though.