Platonic idealism

Platonic idealism usually refers to Plato's theory of forms or doctrine of ideas. Some commentators hold Plato argued that truth is an abstraction. In other words, we are urged to believe that Plato's theory of ideas is an abstraction, divorced from the so-called external world, of modern European philosophy, despite the fact Plato taught that ideas are ultimately real, and different from non-ideal things—indeed, he argued for a distinction between the ideal and non-ideal realm.

These commentators speak thus: For example, a particular tree, with a branch or two missing, possibly alive, possibly dead, and with the initials of two lovers carved into its bark, is distinct from the abstract form of Tree-ness. A Tree is the ideal that each of us holds that allows us to identify the imperfect reflections of trees all around us.

Plato gives the divided line as an outline of this theory. At the top of the line, the Form of the Good is found, directing everything underneath.

Some contemporary linguistic philosophers construe "Platonism" to mean the proposition that universals exist independently of particulars (a universal is anything that can be predicated of a particular).

Theory of Forms

Plato's theory of Forms or theory of Ideas asserts that non-material abstract (but substantial) forms (or ideas), and not the material world of change known to us through sensation, possess the highest and most fundamental kind of reality. When used in this sense, the word form or idea is often capitalized. Plato speaks of these entities only through the characters (primarily Socrates) of his dialogues who sometimes suggest that these Forms are the only true objects of study that can provide us with genuine knowledge; thus even apart from the very controversial status of the theory, Plato's own views are much in doubt. Plato spoke of Forms in formulating a possible solution to the problem of universals.

Forms

The Greek concept of form precedes the attested language and is represented by a number of words mainly having to do with vision: the sight or appearance of a thing. The main words, εἶδος (eidos) and ἰδέα (idea) come from the Indo-European root *weid-, "see".Eidos (though not idea) is already attested in texts of the Homeric era, the earliest Greek literature. Equally ancient is μορφή (morphē), "shape", from an obscure root. The φαινόμενα (phainomena), "appearances", from φαίνω (phainō), "shine", Indo-European *bhā-, was a synonym.