Wednesday, November 29, 2017

Optative Inference

If we can have imperative logic and erotetic logic, we can surely have a logic of optatives (or euctic logic, if you prefer the Greek).

Suppose, for instance, someone says, "God save the Queen!" From this I can infer, "There is a Queen." If I say, "If only we were rich!", from this you can infer, "We are not rich." If someone says, "May John get well soon!", you can directly infer that John is not well yet.

A very natural way to interpret optative inference would be to take optatives to be assertions about wishing or wanting. If I say, "If only it were so", this does seem to be very much like, "I wish it were so", and the two would at least often be equivalent. This, you will note, is essentially the Bolzano approach; Bolzano thought that questions worked this way, but it's even more plausible with optatives. It does raise a question, though. Bolzano's account of questions naturally has a number of problems, not least that which Husserl noted about its implausibility in dealing with silent wondering. Are there optative analogues to 'silent wondering'?

If optatives are not assertions like this, then truth values need to be answered, and presumably there would be some analogy to imperatives in this way.