I've been following a number of other logic related blogs. Logblog mentioned a conference on exact philosophy. I'm inclined to think it an oxymoron.
On logicandlanguage, there is a reference to Kant's law; that you can't get necessity-style claims from contingent claims. This seems to correspond to my rules that P => P and P => <>P, but not their converses. With caution, it's possible to interpret ?P as "P is contingent", but it's not possible with only 3 values to distinguish "contingently true" from "contingently false", which points to the need of a 4-valued logic. I've worked out the basic truth tables based on my interpretation of 3-valued logic, but I haven't otherwise done much with it. But it isn't the Lukasiewicz 4-valued logic. I've also been discussing the subject on Mathematics and Computation.