What's the difference between assume and presume?

Answer 1

Basically, the difference is this:
We assume something to be true based on the facts we have at hand (if any of the facts change, the assumption also changes). For example, a couple is found dead in their home, each shot. One of them has a gun in his hand. The door was locked, there are no signs of forcible entry. We assume the one with the gun committed murder/suicide, based on the facts in evidence. However, if the facts change (evidence of someone else's presence, no gunshot residue on the hands of the one with the gun, etc.), the assumption can change.

A presumption, on the other hand, is made absent any facts, and will remain until and unless any facts are asserted to the contrary. For example, a husband is legally presumed to be the father of his wife's child, so long as they are married at the time of the child's birth or, if divorced, the child was conceived during the marriage. No statement of paternity or testing is needed to place the man's name on the birth certificate. He is presumed to be the father until and unless that presumption is challenged and proven.

Answer 2

Assume: 1. to take for granted or without proof; suppose; postulate; posit: to assume that everyone wants peace.
2. to take upon oneself; undertake: to assume an obligation.
3. to take over the duties or responsibilities of: to assume the office of treasurer.

Presume : 1. to take for granted, assume, or suppose: I presume you're tired after your drive.
2. Law. to assume as true in the absence of proof to the contrary.
3. to undertake with unwarrantable boldness.
4. to undertake (to do something) without right or permission: to presume to speak for another.

Answer 3

In dictionary.com, presume and assume are each defined in one of the definitions as "take for granted". But for "assume, it says "take for granted, presume', and for "presume" it says"take for granted, assume".
From that they seem to be synonymous, but Patricia T. O'Conner, in "Woe Is I: The Grammarphobe's Guide To English in Plain English (pp 90-91) writes,
"They're not identical. Assume is closer to suppose or 'take for granted'; the much stronger presume is closer to believe, dare, or 'take too much for granted'.
I can only assume you are joking when you presume to call yourself a plumber".

AskOxford.com says" The New Oxford Dictionary of English, which is based on recent usage evidence, provides these definitions:
assume- suppose to be the case, without proof.
presume-suppose that something is the case on the basis of probability; take for granted that something exists or is the case".

From these examples it seems to me that "presume" implies "take for granted in the absense of any other evidence to the contrary". I presume something is true until you show me it is not.
"Assume" seems to mean " to hold as true, to postulate, without direct evidence to support the claim".

Answer 4

ASSUME:
1. TO TAKE AS TRUE before there is proof.
2. To undertake.
3. To take upon or for oneself something not genuine or sincere.

PRESUME:
1. To SUPPOSE to be true; to take for granted.
2. To venture, to take the liberty.
3. To take an unfair advantage of.

Answer 5

Assume - takes the passive voice.

Presume - takes the active voice.

Answer 6

assume=would
presume=could