This man refuted Nietzsche's master-slave morality
This man refuted Nietzsche's master-slave morality in Power: A New Social Analysis and distinguished between knowledge by acquaintance and knowledge by description in The Problems of Philosophy. He treated sentences about the "present king of France in his "On Denoting," and he labeled churches as the "principle enemy of moral progress" in one work, and in another work he attempted to cast mathematical objects as Platonic ideals and asked whether the set of all sets contains itself in his namesake paradox. For 10 points, identify this philosopher of Why I am not a Christian, who with Alfred Whitehead co-wrote Principia Mathematica.
This man refuted Nietzsche's master-slave morality in Power:
{Bertrand} Arthur William {Russell} [or 3rd Earl {Russell}]