Epistemic "must"

[cbonial]

How should we handle cases of "must" that aren't deontic (permission, obligation), but rather are epistemic? For example, "John isn't here, he must be sick."

We only have cases of "must" that correspond to "obligate," but that doesn't fit here. We considered using "probable" but "John isn't here, he MAY be sick" doesn't seem to quite capture the same thing.

This could also occur with other modals "He's gotta be/has to be sick if he's not here," etc.

[nschneid]

Hmm...I think this could be read as "likely cause-of":

John isn't here, he must be sick.

(b / be-located-at-91 :polarity -
      :ARG1 (p / person :name (n / name :op1 "John"))
      :ARG2 (h / here)
      :ARG1-of (c / cause-01
            :ARG0 (s / sick
                  :domain p)
            :mod (l / likely)))

Or maybe there's a good frame to recruit for this purpose (indicate-01?).

[uhermjakob]

Would this be an inference? Maybe we can use infer-01 of deduct-01. One precedent: I think, therefore I am. (deduce-01)

[uhermjakob]

Consensus (AMR phone meeting May 28, 2013):

    (i / infer-01
      :ARG1 (s / sick
                 :domain p)
      :ARG2 (b / be-located-at-91 :polarity -
                 :ARG1 (p / person :name (n / name :op1 "John"))
                 :ARG2 (h / here)))

[nschneid]

Should this go in the guidelines under modality?

[cbonial]

That placement in the guidelines makes sense to me, this could be contrasted to other "must" usages.