Aquinas's discussion of sin provides a good point of entry to his philosophical explanation of why the nature of God is the standard for value. "Every sin," he writes, "consists in the longing for a passing ultimately unreal or false good." Thus, "in a certain sense it is true what Socrates says, namely that no one sins with full knowledge." "No sin in the will happens without an ignorance of the understanding." God, however, has full knowledge (omniscience) and therefore by definition (that of Socrates, Plato, and Aristotle as well as Aquinas) can never will anything other than what is good. It has been claimed – for instance, by Nicolai Hartmann, who wrote: "There is no freedom for the good that would not be at the same time freedom for evil" – that this would limit God's freedom, and therefore his omnipotence. Josef Pieper, however, replies that such arguments rest upon an impermissibly anthropomorphic conception of God. In the case of humans, as Aquinas says, to be able to sin is indeed a consequence, or even a sign, of freedom ("quodam libertatis signum"). Humans, in other words, are not puppets manipulated by God so that they always do what is right. However, "it does not belong to the essence of the free will to be able to decide for evil." "To will evil is neither freedom nor a part of freedom." It is precisely humans' creatureliness – that is, their not being God and therefore omniscient – that makes them capable of sinning. Consequently, writes Pieper, "the inability to sin should be looked on as the very signature of a higher freedom – contrary to the usual way of conceiving the issue." Pieper concludes: "Only "the" will God's can be the right standard of its own willing and must will what is right necessarily, from within itself, and always. A deviation from the norm would not even be thinkable. And obviously only the absolute divine will is the right standard of its own act" – and consequently of all human acts. Thus the second horn of the Euthyphro dilemma, divine command theory, is also disposed of.