Underivability Results in Mixed Systems of Monadic Deontic Logic

The intention of this essay is to demonstrate some results of underivability for certain mixed deontic systems that also include the bridge­ principle: Ought implies Can. Secondly, it will be shown that the independence result, suitably weakened, can be extended to even more powerful systems. In particular proof will be given of the independence of a restricted class of formulae of obligation (axiologically important obligations) within the framework of the powerful alethic system of deontic logie KT5Q.