  When combined with the results of D5, this result entails that the one is. To see this, consider the following. D5 establishes that if the one is not, then the one is both F and con-F; and D6 establishes that if the one is not, then the one is neither F nor con-F. So if both D5 and D6 are valid and based on acceptable premises, then D5 and D6 together establish that if the one is not, then the one has contradictory properties. Given that it is impossible for something to have contradictory properties, it is a direct consequence of the conjunction of D5 and D6 that it is not the case that the one is not. That is to say, D5 and D6 together entail that the one is.