by Kathleen Watson

Either at home or early in your school days, did you learn about a difference between can vs. may?

Can you (do you have the ability to) have your book report done by noon?

May I (do I have your permission to) read your book report to the class?

According to merriam-webster.com, can still is the verb of choice for ability, but both can and may are acceptable to express permission.

But at oxforddictionaries.com, there still is a widespread view that using can to ask for permission is wrong and that it should be used related only to ability or capability:

Can you speak fluent French?

The wrestler can pin any opponent he chooses.

Other sources claim there’s only a minor difference between the two verbs: One sounds more polite than the other.

Can we come over and swim in your pool?

May we come over and swim in your pool?

If I can, I’ll ask you a few questions about your job.

If I may, I’ll ask you a few questions about your job.

Moving on to may and might

Now that we have can and may settled — sort of — what is the difference between may and might?

I’ve struggled with this for years, and I’ve conducted multiple Google searches, never feeling satisfied that I fully understood or agreed with what I found.

Some sources say that may and might normally can be interchanged without a significant difference in meaning. Although both convey that there is a chance something is true or there is a possibility of something happening, some sources claim that might implies less certainty:

I wouldn’t talk to Jess right now. He may still be angry about his team’s loss.

Ella is so talented, I think she may win the competition.

Although it might rain later, let’s take a chance and make a tee time.

If I can get my project done, I might go to a movie tonight.

I fail to see enough of a difference in the nuance of may or might to have concerns about which to use.

May versus might in academic, technical writing 

I have found that may, rather than might, is used almost exclusively in the academic writing I’ve edited. However, the near-universal use of may raises potential for misinterpretation.

For example:

This research may be used for teaching purposes.

Is the author, despite holding the copyright for the material, giving broad permission for its use in a classroom?

Or is the author implying there’s a possibility the research could be relevant to include in developing curriculum?

One may use the entire set of data for projecting results.

Again, does this imply permission to use the data for determining results?

Or does it imply that using all of the data will yield appropriate projections of results?

Two editors, one in technical and one in academic writing, avoid may:

“In editing technical writing,” says the first, “I never allow ‘may,’ because it is too ambiguous:

“Other programs may be started during installation.”

Does this mean the installer can initiate other programs that are part of the installation process? Or does it mean the installer can begin to watch “Game of Thrones” as the installation runs?

The academic editor says, “I habitually edit “may” to “might” for possibility and “can” for ability.

The choice is yours

Reflecting on the websites I’ve visited and the explanations and examples I’ve found, I still am not convinced there is enough difference between may and might to worry about in most usage.

However, as a professional writer and editor, I will continue to watch for potential misunderstanding with may: There could be a significant difference in meaning when it is not clear whether it implies permission or simply possibility.

I trust you can figure out which to use, but you might still have questions. If that’s the case, you may contact me.