 Hume rejects both these metaphysical arguments for the immateriality and immortality of the soul. His refutations are presented, first, in the Treatise 1.4.5–6 and, later and more briefly, in his essay “Of the Immortality of the Soul”. (It is possible that this essay contains material that was originally intended for publication in the Treatise but was withdrawn.) Regarding the suggestion that thought and consciousness must belong to or inhere in an immaterial substance, Hume objects that we have no idea of either immaterial or material substance.