  An issue to do with the grammatical properties of proper names was whether they could be pluralized or quantified. Most people said that no plural could be grammatically correct, and that such phrases as ‘every Socrates’ were ill-formed, but various logicians in late fourteenth-century Oxford pointed out that such locutions as “There are several Roberts” or ‘every William’ had their uses in ordinary speech, even if they were somewhat deviant. The use of demonstratives with proper names could also pose a problem. Domingo de Soto remarked that in the case where there are several people called Peter in the room, and we want to distinguish this Peter from that Peter we may speak of this or that Peter, but in the mind, where there are no equivocal concepts, the singular concept corresponding to a proper name cannot properly be further singularized, any more than it can be universalized.