Abstract I have recently discussed whether omnipotence and omniscience are incompatible i.e. a being cannot have both properties at the same time. Much of the discussion was centered around an argument I invented some time ago. But before we look at the argument, we need to clarify what it meant by the concepts used. The important concepts employed are omnipotence, omniscience and 'possible'. Possible will be discussed later in the paper than the other two.