 The issue of individual natures also affected the way in which the newly developed theory of supposition was presented, since it emphasised the fact that terms could exhibit a variety of semantic features. Thus one and the same term could have material supposition when it referred to the actual word, as in “‘man’ has three letters,” or simple supposition when it referred to the form signified, as in “Man is a species of animal,” or personal supposition when it referred to individuals, as in “Some man is running.” Certainly singular terms could have material supposition, but, at least for non-nominalists, the distinction between simple or formal supposition and personal supposition was more problematic. Either singular terms lacked a semantic property that common nouns had, or singular terms could stand for an individual nature. William of Sherwood explicitly allowed the singular term ‘Socrates’ to have formal supposition in the sentence “Socrates is said of just one individual”, on the grounds that ‘Socrates’ does signify a form, but he went on to deny that the term had the further property of appellation, which belonged to predicates, because, unlike common nouns, it could not properly function as a predicate. However, other thirteenth-century logicians tended to by-pass the problem of whether what they took to be fundamental semantic features all applied equally to both singular terms and common nouns.