 Cocchiarella (1977) presents a formal language, though no axioms or rules, for a logic of sortals which includes both tense and modal operators. His approach, like Wiggins, considers sortals to be concepts. Unlike Wiggins he gives a definition of “sortal concept”: as a socio-genetically developed cognitive ability or capacity to distinguish, count and collect or classify things (1977: 441). He disagrees with Wiggins on both principles  (i) and (ii) above, arguing that while they may be true for natural kind terms, there are no reasons to believe that there are ultimate sortals of which various artifact sortals are restrictions, nor that every intersection of sortals must fall under an ultimate sortal. Cocchiarella’s approach also goes beyond Stevenson’s in that it involves second-order logic, i.e., it includes quantification over sortal concepts.