Abstract
PLATONISM or platonic realism in logic and mathematics is probably the most widespread contemporary view in the philosophy of mathematics. It has become popularly identified with the acceptance of an ontology of sets and/or classes as fundamental among the building materials of the cosmos and of all that is therein. Usually, also, these entities are regarded as "abstract" rather than "concrete," but no one has given us a sufficiently detailed and acceptable theory as to how this dichotomy is to be drawn. Sets and classes are taken somehow as the paradigm of abstract entities, as over and against something called 'individuals', which are then the paradigm of concrete entities. This is all very unsatisfactory and in need of much analysis and clarification.