Ross's paradox & Revealed deontics

In Islam, statements are of two sorts- insha, that is imperative or deontic, and khabar, that is factual. Normative use of the hadith literature, in Islam, applies a sort of imperative logic with the result that different sects condemn each other as apostates, polytheists, grave-worshipers and so on.

Now, if Man evolved by natural selection, we would expect imperative logic to actually be more rather than less interesting than formal logic.

Consider 

Ross's Paradox (Ross 1941):

1) It is obligatory that the letter is mailed.
(2) It is obligatory that the letter is mailed or the letter is burned.

To my mind, this adds something to the notion of what imperative or deontic statements do- what they must do if Man evolved by natural selection-and that is they open up more possibilities for free choice, more methods of individuation, more avenues of rebellion, precisely when they pile up on each other to push one down a path narrower than the sword's edge and suspended over an abyss.