MAY HAVE AND MIGHT HAVE;
PAST COUNTERFACTUALS

© 1998, 1999, 2001 by Orchid Land Publications

[updated 2-23-01]

     One has only to listen to TV announcers and public officials to realize grave problems attend the distinction between may have and might have for past potential predicates; and that past counterfactuals are a major problem in current English.
     May expresses a potential reality, while might carries additional overtones of doubt--at least when it does not replace my after a past predication in a main clause that the clause containing may/might is dependent on.  Contrast, "They may leave soon" and "They may have left by now" with "They might leave soon" and "They might have left by now."  When these modal verbs occur in a dependent clause, the uses are exemplified in these sentences:

     We thought that they might (not) leave soon. (never may)
     She's thinking that we may (not) leave soon.    (possible)
     He's thinking that they might (not) leave soon. (doubtfully                                                                                possible)

In short, when the main predicate is a past, may is not used.  But note this error by an Oxford University Press author:  "[A certain east-European country] MAY have been brought within the [empire], but it WAS by no means tamed . . . "

      Potential may and might  are used exactly like potential can and could, respectively:

potential  MAY (HAVE)	used for possibilities in non-past time; may have is used for possibility in any past time up till now; e.g. "They may (have) put it there."  One cannot say "It may have survived" when it is known that it didn't survive or hasn't survived!
conditional-potential MIGHT (non-past)	used for a doubtful non-past possibility; obviously  NOT SUITED for direct (non-quoted) PRAYERS; e.g. "They might (have) put it there."  Note:  "It might have survived if such and such had not happened."
conditional-potential MIGHT (HAVE) (past) past-posterior	used for doubtful possibilities in past time; e.g. "They might have put it there yesterday";  "They said that it might arrive on time."
permissive MAY	non-past; e.g. "You may stay."
permissive MIGHT	with a past verb; e.g. "She said they might stay."
permissive MAY interrogative	direct, polite offer; e.g. "May I help you?"
permissive MIGHT interrogative	more hesitant polite offer; e.g. "Might I inquire where you are from?"

     If we wish to speak of a past event that did not take place, we say:

     If he had been here, it would not have happened.
     If he hadn't been there, the victim would have died.

Note that in the hypothesis clause (beginning with if), we throw the time back a degree to indicate counterfactuality; the contingency clause has would have.  There is a tendency today for many to say would have in the hypothesis clause also.   Cultivated speakers may soon be doing this; but they don't yet.  The worst usage is simply to use a past:

    If she was (not) there, that wasn't any of their business.

Note that the foregoing is correct if we are simply stating a hypothesis without any assumptions about whether the statement, "she was (not) there" is true or false.  There are two other usages in place of the past-anterior (formed on have) in addition to the foregoing two.  One is to misuse were (it is proper for a present counterfactual hypothesis), as in:

     They wondered whether he were there yesterday. 

A fifth usage, one with more linguistic logic, is the widespread use of the double past-anterior (found also in French and German, but functioning differently from the English example), as in:

     If they had've (hadda) been on time, that wouldn't've happened.

      In passing, it may be observed that we throw back the time for counterfactuality in present and for unexpectedness or doubt regarding a future predicate; in the following pairs of examples, the (a) item is not counterfactual/counterexpectative/ dubitative, whereas the (b) item is:

1a. If she's there now . . .
1b. If she was/were there now . . .

2a. If she is late tomorrow . . .
2bi. Is she were (to be) late tomorrow . . .
2bii. If she should be late tomorrow . . .

(Note in the last item that should used to be the past of shall.) 

     It is difficult to account for the particular reversal of may and might in much English, since it does not take place with parallel can and could.   (The matter is complicated by the fact that both pairs have, in linguistic jargon, epistemic as well as deontic usages--and may has got four usages in all, while can/could have a third [root] use (cf. Essays on time-based linguistic analysis [Oxford University Press, 1996], p.242).  There are curious switchings of the may and can, which the author has discussed in ibid., p. 234, n. 29; cf. pp. 175, 215.)  Current linguistic theory of course recognizes the rôle of switches in marked environments, but any may/might switching is hard to account for without a parallel can/could switch.   For the moment, replacing might and may with each other remains unaccounted for.
     Note this error on a bank's online agreement form:

If we recredited your Deposit or Credit 
Account, we will also notify you.

Since this is a timeless or a posterior statement, it is necessary to use the exochronous-anterior:  "If we have (ever; in the future) recredited, . . ."

  SEE ALSO HERE & HERE & HERE