 The concept has since been taken up by a variety of thinkers and theorists such as roboticist Masahiro Mori's uncanny valley and Julia Kristeva's concept of abjection.Philosopher F. W. J. Schelling raised the question of the uncanny in his late "Philosophie der Mythologie" of 1835, postulating that the Homeric clarity was built upon a prior repression of the uncanny.In "The Will to Power" manuscript, German philosopher Friedrich Nietzsche refers to nihilism as "the uncanniest of all guests" and, earlier, in "On the Genealogy of Morals" he argues it is the "will to truth" that has destroyed the metaphysics that underpins the values of Western culture.