CONCEPTUALISM (from " Concept ")  , in philosophy, a term applied by modern writers to a scholastic theory of the nature of universals, to distinguish it from the two extremes of Nominalism and Realism . The scholastic philosophers took up the old Greek problem as to the nature of true reality—whether the general idea or the particular object is more truly real . Between Realism which asserts that the genus is more real than the species, and that particulars have no reality, and Nominalism according to which genus and species are merely names (nomina, flatus vocis), Conceptualism takes a mean position . The conceptualist holds that universals have a real existence, but only in the mind, as the concepts which unite the individual things: e.g. there is in the mind a general notion or idea of boats, by reference to which the mind can decide whether a given object is, or is not, a boat . On the one hand " boat " is something more than a mere sound with a purely arbitrary conventional significance; on the other it has, apart from particular things to which it applies, no reality; its reality is purely abstract or conceptual . This theory was enunciated by Abelard in opposition to Roscellinus (nominalist) and William of Champeaux (realist) . He held that it is only by becoming a predicate that the class-notion or general term acquires reality . Thus similarity (conformitas) is observed to exist between a number of objects in respect of a particular quality or qualities . This quality becomes real as a mental concept when it is predicated of all the objects possessing it (" quod de pluribus natum est praedicari ") . Hence Abelard's theory is alternatively known as Sermonism (sermo, " predicate ") . His statement of this position oscillates markedly, inclining sometimes towards the nominalist, some-times towards the realist statement, using' the arguments of the one against the other . Hence he is described by some as a realist, by others as a nominalist .

When he comes to explain that

objective similarity in things which is represented by the class-concept or general term, he adopts the theological Platonic view that the ideas which are the archetypes of the qualities exist in the mind of God . They are, therefore, ante rem, in re and post rem, or, as Avicenna stated it, universalia ante multiplicitatem, in multiplicitate, post multiplicitatem .