I've been having a long-running discussion with my sub-editor regarding observations of the word 'assume' (or derivatives), where (classically) the word 'presume' should be preferred. What's the difference? Ignoring complication: 'assume' is something you take upon yourself (assume a role or a position), and 'presume' is to make a guess prior to confirming data ("Dr Livingstone I presume"). How to tell when 'presume' would be appropriate rather than 'assume'? If you can rearrange the sentence to begin 'Presumably' (since there is no word 'Assumably'), don't use 'assume'. However, it has been noted that 'assume' occurs very often where 'presume' would be indicated by the above rule, in common modern usage, across all media. The reason for this slippage is that every use of 'assume' instead of 'presume' reinforces itself in the general subconcious, until it becomes the norm. So when did this slippage begin? I was reading something this morning which shook me: "...and the mathematical investigations given in special articles marked with an asterisk (*). This plan has been followed throughout the book, so the general reader can evade all the mathematical investigations, but it must not be assumed that articles so marked are difficult to understand..." Foreword to the Admiralty Manual of Tides, 1941 (my underlining) Assume/Presume thus joins my catalogue in the same category as Curious/Inquisitive.