4) Any Positive obligation must be constantly being fulfilled at all times? I am able to cobble up an elaborate explanation of this idea of Molyneux's, but I am still tempted to count it as a reductio ad absurdum. That is, if I can reason to that conclusion, some of my assumptions must be wrong. The fact that the argument is so elaborate is a danger sign. At the very least, Molyneux needs to explain this better, because it is a very surprising result. He treats it almost as obvious. He bases the idea on universality. Why not think of a positive obligation in analogy to a gas tank, you have to fill it up before it gets empty?
8) Molyneux begs the question with most of his example tests. Murder is defined as wrongful killing. There is no difficulty proving that wrongful killing is wrong. The difficulty arrives when we try to draw a clear line between wrongful killing and other sorts, such as legitimate self-defense, accident, etc. Molyneux does not draw this line.
As you may have noticed, none of these criticisms is deadly to UPB. The fact that Molyneux has made mistakes doesn't disprove his idea. It just means Molyneux has failed to give us good reasons to think he is right.