Theory of forms
The Theory of Forms or Theory of Ideas, also known as Platonic idealism or Platonic realism, is a philosophical theory credited to the Classical Greek philosopher Plato.
A major concept in metaphysics, the theory suggests that the physical world is not as real or true as Forms : the timeless, absolute, non-physical, and unchangeable essences of all things, which objects and matter in the physical world merely participate in, imitate, or resemble. In other words, Forms are various abstract ideals that exist even outside of human minds and that constitute the basis of reality. Thus, Plato's Theory of Forms is a type of philosophical realism, asserting that certain ideas are literally real, and a type of idealism, asserting that reality is fundamentally composed of ideas, or abstract objects.
Plato describes these entities only through the characters in his dialogues who sometimes suggest that these Forms are the only objects of study that can provide knowledge. The theory itself is contested by characters within the dialogues, and it remains a general point of controversy in philosophy. Nonetheless, the theory is considered to be a classical solution to the problem of universals.
Etymology
Referring to Forms, Plato used a number of Ancient Greek terms that mainly relate to vision, sight, and appearance, including ἰδέα, a word that precedes attested philosophical usage. Plato uses these aspects of sight and appearance in his dialogues to explain his Forms, including the supreme one: the Form of the Good. Other terms include εἶδος meaning "visible form", and the related terms μορφή meaning "shape", and φαινόμενα meaning "appearances", from φαίνω meaning "shine", ultimately from Indo-European '*bʰeh₂-' or *bhā-. The original meanings of these terms remained stable over the centuries before the beginning of Western philosophy, at which time they became equivocal, acquiring additional specialized philosophic meanings. Plato used the terms eidos and idea interchangeably.Pre-Socratic philosophy
The pre-Socratic philosophers, ancient Greek thinkers born before Plato, noted that appearances change, and they began to ask what the thing that changes "really" is. If something changes, what component or essence of it remains "real"? The answer was substance, which stands under the changes and is the actually existing thing being seen. The status of appearances now came into question, including how the appearance is related to the substance. For instance, the earliest known pre-Socratic philosopher, Thales, argued that the fundamental substance all things are made of is water.Scriptures written by Pythagoras, another pre-Socratic philosopher, suggest that he developed an earlier theory similar to Plato's Forms. For Pythagoras, like Plato, the substance or essence of all things was not something physical but rather something abstract. However, Pythagoras's theory was much narrower than Plato's, proposing that the non-physical and timeless essences that compose the physical world are specifically numbers, whereas Plato conceived of his Forms as a vast array of intangible ideals.
The Forms are expounded upon in Plato's dialogues and general speech, in that every object or quality in reality—dogs, human beings, mountains, colors, courage, love, and goodness—has a Form. Form answers the question, "What is that?" Plato was going a step further and asking what Form itself is. He supposed that the object was essentially or "really" the Form and that the phenomena were mere shadows mimicking the Form; that is, momentary portrayals of the Form under different circumstances. The problem of universals – how can one thing in general be many things in particular – was solved by presuming that Form was a distinct singular thing but caused plural representations of itself in particular objects. For example, in the dialogue Parmenides, Socrates states: "Nor, again, if a person were to show that all is one by partaking of one, and at the same time many by partaking of many, would that be very astonishing. But if he were to show me that the absolute one was many, or the absolute many one, I should be truly amazed." Matter is considered particular in itself. For Plato, Forms, such as beauty, are more real than any objects that imitate them. Though the Forms are timeless and unchanging, physical things are in a constant change of existence. Where Forms are unqualified perfection, physical things are qualified and conditioned.
These Forms are the essences of various objects: they are that without which a thing would not be the kind of thing it is. For example, there are countless tables in the world but the Form of tableness is at the core; it is the essence of all of them. Plato's Socrates held that the world of Forms is transcendent to our own world and also is the essential basis of reality. Super-ordinate to matter, Forms are the most pure of all things. Furthermore, he believed that true knowledge/intelligence is the ability to grasp the world of Forms with one's mind.
A Form is aspatial and atemporal. In the world of Plato, atemporal means that it does not exist within any time period, rather it provides the formal basis for time. It therefore formally grounds beginning, persisting and ending. It is neither eternal in the sense of existing forever, nor mortal, of limited duration. It exists transcendent to time altogether. Forms are aspatial in that they have no spatial dimensions, and thus no orientation in space, nor do they even have a location. They are non-physical, but they are not in the mind. Forms are extra-mental.
A Form is an objective "blueprint" of perfection. The Forms are perfect and unchanging representations of objects and qualities. For example, the Form of beauty or the Form of a triangle. For the form of a triangle say there is a triangle drawn on a blackboard. A triangle is a polygon with 3 sides. The triangle as it is on the blackboard is far from perfect. However, it is only the intelligibility of the Form "triangle" that allows us to know the drawing on the chalkboard is a triangle, and the Form "triangle" is perfect and unchanging. It is exactly the same whenever anyone chooses to consider it; however, time only affects the observer and not the triangle. It follows that the same attributes would exist for the Form of beauty and for all Forms.
Plato explains how we are always many steps away from the idea or Form. The idea of a perfect circle can have us defining, speaking, writing, and drawing about particular circles that are always steps away from the actual being. The perfect circle, partly represented by a curved line, and a precise definition, cannot be drawn. The idea of the perfect circle is discovered, not invented.
Intelligible realm and separation of the Forms
Plato often invokes, particularly in his dialogues Phaedo, Republic and Phaedrus, poetic language to illustrate the mode in which the Forms are said to exist. Near the end of the Phaedo, for example, Plato describes the world of Forms as a pristine region of the physical universe located above the surface of the Earth. In the Phaedrus the Forms are in a "place beyond heaven" ; and in the Republic the sensible world is contrasted with the intelligible realm in the famous Allegory of the Cave.It would be a mistake to take Plato's imagery as positing the intelligible world as a literal physical space apart from this one. Plato emphasizes that the Forms are not beings that extend in space, but subsist apart from any physical space whatsoever. Thus we read in the Symposium of the Form of Beauty: "It is not anywhere in another thing, as in an animal, or in earth, or in heaven, or in anything else, but itself by itself with itself,". And in the Timaeus Plato writes: "Since these things are so, we must agree that which keeps its own form unchangingly, which has not been brought into being and is not destroyed, which neither receives into itself anything else from anywhere else, nor itself enters into anything anywhere, is one thing,".
Ambiguities of the theory
Plato's conception of Forms actually differs from dialogue to dialogue, and in certain respects it is never fully explained, so many aspects of the theory are open to interpretation. Forms are first introduced in the Phaedo, but in that dialogue the concept is simply referred to as something the participants are already familiar with, and the theory itself is not developed. Similarly, in the Republic, Plato relies on the concept of Forms as the basis of many of his arguments but feels no need to argue for the validity of the theory itself or to explain precisely what Forms are. Commentators have been left with the task of explaining what Forms are and how visible objects participate in them, and there has been no shortage of disagreement. Some scholars advance the view that Forms are paradigms, perfect examples on which the imperfect world is modeled. Others interpret Forms as universals, so that the Form of Beauty, for example, is that quality that all beautiful things share. Yet others interpret Forms as "stuffs", the conglomeration of all instances of a quality in the visible world. Under this interpretation, we could say there is a little beauty in one person, a little beauty in another – all the beauty in the world put together is the Form of Beauty. Plato himself was aware of the ambiguities and inconsistencies in his Theory of Forms, as is evident from the incisive criticism he makes of his own theory in the Parmenides.Evidence of Forms
Human perception
In Cratylus, Plato writes:But if the very nature of knowledge changes, at the time when the change occurs there will be no knowledge, and, according to this view, there will be no one to know and nothing to be known: but if that which knows and that which is known exist ever, and the beautiful and the good and every other thing also exist, then I do not think that they can resemble a process of flux, as we were just now supposing.
Plato believed that long before our bodies ever existed, our souls existed and inhabited heaven, where they became directly acquainted with the forms themselves. Real knowledge, to him, was knowledge of the forms. But knowledge of the forms cannot be gained through sensory experience because the forms are not in the physical world. Therefore, our real knowledge of the forms must be the memory of our initial acquaintance with the forms in heaven. Therefore, what we seem to learn is in fact just remembering.