Is the theory of forms valid?

socrates, plato, aristotle were part of a development of western thought, they were not individually the ends of western civilization's philosophical thought. they are comparable to asking: existence, non-existence, and both existence and non-existence. existence is the physical nature, non-existence is the spiritual nature.
in a cause and effect relationship, the indic thought of shakyamuni (1028--949 B.C.) expressed the two truths of daily life, and the truth of life and death. when the chinese received these teachings in (67 A.D. ) they were understood as by t'ien-t'ai ( 549 A.D.), that life is mind, body. life is considered the middle way between the separation of body and mind, or saying that the unification of the two is this life. so life is called the truth of the middle way.

to plato, the separation of mind and body resulted in his ideas of forms as a separation of spiritual-material realities. he created the development of the paranormal and supernatural spiritual world. this exists only as an abstract idealism. according to c.jung, this is psychologic projection.
the consequences of this separation is continued today as christian thought.
thus, we have confusion in the philosophical nature of western civilization.

Plato very well might have been misunderstood on that, first by Aristotle and then up to now.


Stewart felt that many commentators had missed Plato's point in his theory of Ideas because they had not asked the basic question: what human and psychological experience was Plato talking about? They had tended to make Plato's ideas seem fantastic because they had not related them to the facts of present human psychology. Only in this way could the origins of his Plato's theory be discovered.

The cardinal question is not asked: What has present-day psychology to tell us about the variety of experience which expresses itself in the doctrine of Ideas? The doctrine is treated as if it were a 'past event' in the 'history of philosophy' for determining the true nature of which there is such and such documentary evidence which, if only marshalled in the right way, is in itself conclusive. (2)

To the exegetes of Plato Stewart asks:

"But," we ask, "What are the Ideas?" What were Plato and these other people talking about? Surely about the right way of expressing some experience which they all had in common, and we ourselves still have. Tell us in the language, vernacular or philosophical, of today what that experience is."

I think it has become a platform for people to discuss or argue about things.

Quote:

Plato's theory of Forms or theory of Ideas argues that non-physical (but substantial) forms (or ideas) represent the most accurate 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 objects of study that can provide knowledge; thus even apart from the very controversial status of the theory, Plato's own views are much in doubt. However, the theory is considered a classical solution to the problem of universals.

The early Greek concept of form precedes attested philosophical usage and is represented by a number of words mainly having to do with vision, sight, and appearance. The 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. This transliteration and the translation tradition of German and Latin lead to the expression "theory of Ideas." The word is however not the English "idea," which is a mental concept only.

Unquote

A brief answer. May add some references to it later.

If one notes a) the mathematics of physics such as in string theory and in cosmology (particularly in terms of the universality of energy law producing spheres (both ideal models, and as modified in physis)), and b) the activity of electromagnetism in nuclei and in spherical light, then the Platonic Forms as such reflect the Oneness of (the) Good, or God--this "explains" the "nature" of reality at a simple yet universal level. It should be noted that the dianoia level of Form-awareness ought be accompanied by the noesis level of Form-awareness, else one devolve unwittingly into primarily Kantian phenomenalism and even dogmatic reductionism.

Notions of symmetry and completion (the latter a function of sphericity and as "Justice"), i.e. Kantian aesthetic notions of human virtue and beauty, are in accord with the universe as a Oneness, even a sphericity. As Hegel noted, Kant simply did not go far enough (i.e,, to experience Mind as Noumenal).

The point of "validity" and even "soundness" of the ToF is that it is, like so much of Plato's work, fundamental and insightful; because few have built upon it (as e.g. Plotinus has, with his "One Mind Soul"-Realization; "Return to the One: Plotinus's Guide to God-Realization," Brian Hines), the general development of the Platonic potential, which is of fundamental, general, and substantial insight, has primarily remained at the basic level of e.g. "What is the Good?", "Why is there something?", "Is God?", "Am I immortal?", "What is Mind?", and "footnotes" thereunto. Plotinus-type levels of innerstanding have progressed further (as "footnotes" to the basic Ideas or Forms Plato taught), and so if one does not e.g. understand the "spherical nature" of reality, particularly that of Light as Truth, as given in the Cave parable, then one's mentation is more at the "cave dwelling" or Kantian 5-sense phenomenological level, where even terms such as "transcendental" are (perhaps unwittingly) applied to scientistic (reductionist) phenomena. Contemporary examples of the blending of Kantian-level awareness with physics and maths include Peter Sloterdijk, "Bubbles: Spheres Volume I: Microspherology," Gilles Deleuze and Felix Guattari, "A Thousand Plateaus: Capitalism and Schizophrenia," and Byung-Chul Han's "The Transparency Society." These are examples of the work of contemporary professional philosophers that I find meritorious (there are others working in this general Heideggerian/maths-physics area, but imo less substantive).

Valid? Yes, more or less.

All encompassing and totally comprehensive? No. Nothing ever really is.

Platonism is nonsense. Forms are a ridiculous idea.