Many theories have been propounded to explain this system. The Jamiat has propounded a theological basis for its nationalistic philosophy. In a talk delivered at IIT Madras, he propounded debunked theories about water memory. They follow the Dvaita philosophy propounded by Madhvacharya. Although Crippen never gave any reason for killing his wife, several theories have been propounded. Even before he had propounded the atomic theory, Dalton had attained a considerable scientific reputation. Anselm of Canterbury propounded the ontological argument in his "Proslogion". Most Iyers are followers of the "Advaita" philosophy propounded by Adi Shankara. Labriola especially propounded a brand of Hegelian Marxism that he labelled "philosophy of praxis". M. N. Srinivas first propounded this theory in his D.Phil. More generally, writers have propounded Marxist and feminist interpretations of contract. In the 1950s, Immanuel Velikovsky propounded catastrophism in several popular books. The view that Cassian propounded Semipelagianism has been disputed. In brief, Saussure's structural linguistics propounded three related concepts. However, Freeman's ideas did not go unchallenged, even as they were being propounded.