Jean’s question: “Could you please clarify the correct use of “can” and “may” in a future issue? I am finding that ‘can’ is being used exclusively and that ‘may’ no longer appears in business communication. It’s another death of civility, as far as I am concerned.”
BizWritingTip response: I remember one elementary school teacher who always replied to the question “Can I go to the bathroom?” with “I don’t know. Can you?” You could never leave the classroom until you asked “May I go to the bathroom.”
“May” indicates possibility or permission or is used to express a wish
May I attend the conference? (seeking permission)
May you enjoy the conference. (expresses a wish)
Call me if you think I may be of help. (expresses possibility)
“Can” refers to ability or actual possibility.
I can prepare the response by Friday. (has the ability)
The unusual winter can create problems for the economy. (very strong possibility)
Call me if you think I can be of help. (have the ability)
But horrors! With regard to permission, The Chicago Manual of Style and the Oxford Dictionary now say that colloquially (for informal conversation) you may also use “can.” So it is now all right for students to say “Can I … ?”
However, the dictionary goes on to say that in formal settings, “may” is preferred as “can” also expresses physical ability.
Examples (when speaking/writing formally)
Can the files be moved to the fourth floor? (Can someone physically move the files?)
May the files be moved to the fourth floor? (Do we have permission to move the files?)