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.