 Simon’s position as regards empty reference is crucially different from the one held by modists such as Boethius of Dacia and Radulphus Brito, who claim that the truth-makers of essential predications, as ‘man is an animal’, are real things in the external world, so that ‘man is an animal’ would be false if no man  existed.[7]  Simon, however, claims that it is true, supporting his claim with a careful account of truth-determination. According to him, for an essential predication such as ‘man is an animal’ to be true, it suffices that the quiddities expressed by the subject and the predicate are understood and signified. They must be understood because ‘man is an animal’ expresses the mental composition of man and animal, which evidently requires man and animal to be understood (Ebbesen 1987: 159). They must also be signified because otherwise, ‘man is an animal’ would have no content at all—it cannot simply express an empty thought. However, ‘man’ and ‘animal’ do not need to refer to or signify real things in the external world.