I am trying to write a grammar rule that will be able to identify when to use someone or anyone, and I got confused. I couldn't find any clear way to do this.

For instance, "anyone can do it" is totally different from "someone can do it", but since both are pronouns referring to unknown entities, it's extremely difficult to predict the correctness of the grammar.

Any suggestions or am I missing something?


3 Answers 3


You are correct. There is no clear way to do this. Robin Lakoff's paper entitled "Some Reasons Why There Can't Be some ~ any Rule" is precisely about this situation.

Short summary of a few of the reasons:

  1. Any is a Negative Polarity Item, but some isn't.
  2. Many environments (like questions) allow NPIs like any, but don't disallow some.
  3. There are several kinds of any, including NPI any, and "Free Choice" any, as in
    • Any idiot can solve this problem.
  • 2
    Really quite unfortunate, English seems to be really so ambiguous and sorta incomplete, I don't see why no one care about changing it. It just frustrates the idea of artificial intelligence... :( Commented Oct 26, 2012 at 19:30
  • Why try to change what English speakers do? You might as well try to change their religions. Change artificial intelligence instead; that, at least, is potentially improvable. For one thing, synchronize intonation, stress, rhythm, gaze direction, and brow movement with the sound. Ignore written English; it's just a frozen obsolete version of AI (0.002 Beta; 0.001 was Latin). Commented Oct 26, 2012 at 22:38
  • 1
    Funny enough, some people already saw this problem and developed ROILA... Commented Oct 26, 2012 at 22:46
  • @ChibuezeOpata Artificial Intelligence is no match for natural languages.
    – Kris
    Commented Nov 14, 2012 at 6:54
  • And I'll prove you and any other willing to stand by your side wrong :) Commented Nov 14, 2012 at 6:57

Someone can do it.

There is at least one person who can do it. The others may or may not be able to do, it is not stated.

Anyone can do it.

Every single member can do it. There is no one who cannot do it.

  • 1
    This is only true when there is a possibility modal like can in the sentence. Try a sentence frame like ".... did it yesterday" for contrast. Commented Oct 26, 2012 at 16:42

Use "someone" when some elements of a certain group are involved, but not all of the elements. So "someone can do it" means that not everyone from that group can do it, but some can.

Use "anyone" when all elements of a group are involved, but you don't necessarily mean all of them. So "anyone can do it" would mean that everybody in that group could do it, even though it doesn't take them all to do it.

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