When is it better to use "presume" instead of "assume"; or, does it make no difference?

snuiteke

Both words have numerous definitions in the OED, but in ordinary usage, both assume and presume mean “suppose.” I suppose you are going to the beach this summer. I assume you are going to the beach this summer I presume you are going to the beach this summer. H.W. Fowler’s opinion was that in using presume, the speaker believes the supposition is true and will believe it until he learns otherwise. In using assume, the speaker feels no certainty that his supposition is true or not. In a legal context, presume means “to take as proved until contrary evidence is presented.” Ex. The defendant is presumed innocent. Because of the association of the word presume with legal contexts, it carries a connotation of formality. For the fiction writer, presume would be the preferable choice in the speech of a remote or officious character. http://www.dailywritingtips.com/is-there-a-difference-between-assume-and-presume/ The words assume and presume can sometimes share similar meanings; In many cases, these words can be used interchangeably. Presume means to believe something to be true without proof of non-contrary evidence. But assume means to suppose, postulate, claim something is true without checking or confirming it. First presume: Presume comes from the Latin word "præsumere" meaning to 'anticipate taking up' where it moved to Old French "presumer" and then into Middle English with the meaning "to take upon oneself, to take liberty" in 1375. It now has the meaning of "to believe something true without proof of non-contrary evidence." Next assume: Assume comes directly from Latin and actual shares a root with presume, "sumere" means "to take" and "as-" or "ad-" means "to, or up." This gives us the meaning of "to take up" in Latin. This appeared in Middle English as "to take up into heaven" in 1436. Later it took on the meaning of "to suppose something true without checking or confirming it" or "to take up the responsibilities of." The word presume can not be used in the later sense. For example the sentence "Sparky presumed the role of Grand Commander of the Universe." is wrong. The word assume needs to be used instead. http://www.englishspark.com/en/blogs/stumpers/44-teacher-stumpers-article-1 Oct 26 09, 1:44 AM

Zbeckabee

In many contexts when the meaning is 'to suppose', the two words are interchangeable: e.g. I assume/presume you are coming to the party. But, as the Pocket Fowler's Modern English Usage (Ed. Robert Allen. Oxford University Press, 1999) points out, 'Fowler (1926) maintained that there is a stronger element of postulation or hypothesis in assume and of a belief held on the basis of external evidence in presume.' The Oxford English Dictionary definitions are very similar. Assume is 'to take for granted as the basis of argument or action'; presume is 'to take for granted, to presuppose, to count upon'. There is a faint suggestion of presumptuousness about presume. 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. http://www.askoxford.com/asktheexperts/faq/usage/assume?view=uk Oct 26 09, 6:41 AM