“What many things have in common, or a feature they share, is a universal or, in Plato’s terms, a Form. Of course there seems to be a huge number of properties. Many different things are white. Many different things are animals. Each (shared) property is a universal—a ‘one over many instances,’ whiteness over the many white things, roundness over the many round things, and so on. Thus, for Plato, Roundness and Whiteness are Forms.”

This theory is the first known theory of Universals.

The following UML Class Diagram shows the main elements of Plato’s (429?-347 BC) theory of forms:

Plato theory of forms

Class Description Relations Form(p) “Forms are immaterial, non-spatial and atemporal… Forms are… perfect and what particulars strive to be like but fall short of… Forms are simple or incomposite, of one form (monoeidetic). Forms are the objects of knowledge, grasped by the intellect through definitions… Forms are pure, simple or uniform (monoeidetic , hen). One Form takes part in 0, 1, or more Particulars. Good “…all Forms are related to the Good. … each Form is good, that is, that each Form is a good thing or is characterized by goodness.” Good is associated with more (all) Forms (1..*) Essence “Each Form is its essence (ousia), which is to say that the relation of Being links the essence of beauty to the subject, Beauty itself. Being, then, is a primitive ontological relation designed exclusively to capture the special tie between that which possesses an essence and the essence possessed.” Each Form is associated with 1 and only one Essence. Particular “Particulars are dependent on Forms whereas Forms are not dependent on them. Particulars strive to be such as the Forms are and thus in comparison to Forms are imperfect or deficient treat Partaking as a relation between material particulars and Forms, the result of which is that the particular is characterized by the Form of which it partakes…” Each Particular is an aggregation of (at least) one or more Forms (1..*)

Related posts in theory of Universals: [1.2.2], [1.3.1], [1.3.2], [2.5], [2.7.3], [4.3.1], [4.3.2]

The source of all citations and more about the topic in: Silverman, Allan, “Plato’s Middle Period Metaphysics and Epistemology“, The Stanford Encyclopedia of Philosophy (Fall 2014 Edition), Edward N. Zalta (ed.)

First published: 09/01/2019

Updated: 06/02/2019: changed relationship type of Form-Particular