Ernst Mally (11 October 1879 - 8 March 1944) was an Austrian philosopher affiliated with the so-called Graz School of phenomenology. A pupil of Alexius Meinong, he was one of the founders of deontic logic and is mainly known for his contributions in that field of research.
Read more about Ernst Mally: Life, Mally's Deontic Logic, Failure of Mally's Deontic Logic