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Plato's Teaching on the Forms

            If we want to live more philosophically, we may ask, at any moment of importance, what is the truth of this?  We want to interpret the meaning of what we are involved in.  As we inquire, seeking understanding, we are trying to grasp, in the subject at hand, its . . . what?  Its essence?  Its true being?  Something deeper than the passing phenomenon?

            Plato’s efforts to articulate the structures of what the philosophic intellect can meaningfully search for and may discover set the agenda for western philosophy ever since.  Our experience, upon reflection, leads us to acknowledge the reality of intelligible essences, structures, forms, “ideas”—or not.  Philosophers continually rethink the concept of the forms, and many radically dispute Plato, but the only way to dispute him has been to produce an alternate account that seems to explain what Plato is talking about in ways that do not involve Plato’s epistemological and metaphysical commitments.  At first, the topic seems odd, unwelcome, just the sort of thing that makes us run from philosophy.  But any persistently honest reflection on the life of the mind runs into the question about how we interpret the meaning of whatever there is to think about.  Are we grasping a form, more or less clearly, or not?


1.  Our language does not have a well-developed vocabulary for expressing what Plato was talking about with his term form (eidos).  It is necessary to put up with some awkwardness in order to communicate the thoughts in question.  The word "form" is most commonly used by scholars to translate Plato's term eidos Eidos connotes something that has been "seen" (by the intellect).  The term noumenon is just right; it means "an object of the intellect," and the term has become popular through the writings of the Immanuel Kant (1724-1804).  It may help to say that the form is the intelligible structure of a thing, so long as we remember that many forms are simple and as such lack structure.

Sometimes the English word "form" is used to refer to the visible shape of a thing.  This is not Plato's meaning.

The word "idea" is also sometimes used (and Plato sometimes used the Greek word idea), but it is important to remember that a form—an eidos—is not merely an item in someone's stream of consciousness.  Rather it is what thinking grasps or tries to grasp.


2.  How do Plato's teachings connect with ordinary experience and ways of speaking?

            In daily experience we recognize particular things in terms of generalities: "I see a rabbit."  This animal is a particular individual, here and now.  It is also an example of the form or essence—I’ll call it, awkwardly, rabbithood.  (I could call it, following Plato's way of writing more closely, "the rabbit itself," or "the form, rabbit," or "the essence, rabbit.")  We understand each particular in terms of some form or essence.  We intuitively classify what we see.  Thus our perceptions are meaningful.  We grasp not only the particular sensory object but also at the same time the meaning or essence or form involved.

            It is common in conversation to use language that implies that the speaker knows, for example, what is just or right.  Socrates is alert to such assumptions and raises questions to probe whether his interlocutor (conversation partner) actually does understand the meaning of the word he has used.  His challenge is typically expressed as a question, such as, "What is justice?"  In other words, what is the meaning of justice or the essence of justice or the form of justice or the form, justice (please tolerate the many ways to express the thought)?


3.  What motivates some philosophers to talk about forms or essences to begin with?

            Why do we call many things by the same name?  Why do we use the same word to describe different things?  It is, according to Plato, because we recognize that they have something in common.  They, as the phrase goes, participate in, or share in, the same "form."

Another reason to posit the forms is that without some goal, inquiry makes no sense.  Along the path of inquiry, we have the sense of making progress.  Inquiry aims for insight.  Inquiry and insight make no sense if there is nothing real to be sought and found. 

Plato in fact rarely argues for the reality of forms.  He usually simply proposes them to philosophical conversation partners of sufficient maturity, assuming that they recognize the forms and agree with him that they are real and that we can meaningfully inquire into them.

There is an argument in the Phaedo that can be used to support the affirmation of the forms.  When we recognize that two things are equal, we know, without ever having seen perfect equality in material things, that the two things merely approximate perfect equality.  In order to know that these things fall short of perfect equality, we must have some knowledge of the ideal, a knowledge that is not a matter of the experience of the material things around us.  This is another reason to affirm that the intellect has its own proper objects, the forms.

            We are normally not aware of the intellectual aspect of perceptual recognition; but when we see a rabbit, the perceptual sense of the thing before us provides an occasion for the intellectual grasp of rabbithood.  Thus we are able to perceive the thing for what it is.


4.  How broadly does Plato extend his talk of forms?  What sorts of linguistic terms indicate forms?

In some dialogues the forms which Plato mentions as being of greatest interest in many dialogues are beauty, goodness and justice (the beautiful, the good, and the just).  Note: linguistically that these are nouns based on adjectives.  They are not like "rabbit." 

There are other examples, forms of relation and mathematical forms: equality, unity, multiplicity, greatness, and smallness, the number three (not a particular set of three objects that participates in threeness), evenness, and oddness are forms.  The "same" and "different," "motion" and "rest," "being" and "non-being" are terms that indicate forms.  "Soul" and "life" indicate forms.  There are also forms of artifacts such as beds and tables. 


5.  What is the relationship between forms and participant things?

            Each thing has a form.  The form of Socrates is the form, human being (or humanity—the essence).  Each thing also participates in many forms, in virtue of its qualities.  A rabbit is alive, a mammal, small (by comparison with human beings), brown, capable of motion, and so on.  Each of these qualities can belong to many things, and qualities are sometimes called "universals" by philosophers.  Each adjective phrase is associated with one or more forms, e.g., life, mammalhood, smallness, brownness, motion, and so on.

            A thing can participate in contrary essences.  For example, a rabbit participates in smallness and largeness, since it is small by comparison with a hippo and large in comparison with an insect.  As a thing changes, it participates in contrary essences, such as heat and cold, wetness and dryness.

            Can forms participate in contrary forms?  What about likeness and unlikeness?  Are they both like (qua forms) and unlike (qua different)?


Objections and Replies

What objections may be raised to the teaching of the reality of forms, and how could a realist (someone who believes that meanings or forms or essences are real) reply?  Do the objections completely overthrow Plato’s concept, or do they just help us refine it? 

Objection 1.  Wouldn't it be simpler to think of the universe without a bunch of weird forms?

Reply: Progress in physics has found reason to describe the universe as being populated with lots of complex and weird things such as electrons and quarks that we don't readily perceive.  Why should we expect the realm of the mind to be simple?


Objection 2.  Don't different people and groups classify things differently, according to their own interests?  Talk of eternal forms is just a way to invoke transcendent authority in support of limited interests.  

Reply: Someone who affirms the reality of meanings or forms can readily acknowledge the facts of individual and cultural difference, while at the same time persisting in the belief that people all over the world are progressing, converging in understanding, moving toward a common recognition of truth.


Objection 3.  In some cases, where essential distinctions have been alleged, such as the distinction between living and non-living, there are intermediate cases that are hard to classify.

Reply: The fact that there are intermediate cases shows that participation in a form is often a matter of degree. 


Objection 4.  Some things are grouped together with a common name not because they all share one or more common properties (used to define a form) but rather because they exhibit a family resemblance: several of them share some properties, several share other properties, and even though there is no one property that they all share, there is so much overlap in the sets of properties they have that they are classed as a group, given a common name.  This idea was advanced by Ludwig Wittgenstein (1889-1951; Austrian, who studied and taught in England at Cambridge University).  You can recognize the family resemblance of the Jones's kids: most have the same hair color, some a certain sort of nose, etc.  Consider another of his examples: we know how to use the word "game" properly even though there is no one set of properties possessed by all games.

Reply: talk of a common essence is indeed sometimes better replaced by talk of family resemblances, but not every essence is of that sort (as Wittgenstein himself arguably recognized).


Objection 5.  It's harmful to emphasize essential sameness at the cost of noticing difference.  Essentialism suppresses difference.  Is there an essence of woman?  That kind of talk promotes stereotypes.  In social and political contexts, talk of common humanity has been used by Western, male rationalists to impose a conception of the human essence to the detriment of non-western peoples and women. 

Reply: the fact that individual personalities are unique and that groups have important differences does not imply that there is no shared common humanity.  Abuses against various types of people show the need for a more adequate understanding of, and respect for, humanity.  Indeed, many a person who has been mistreated complains of not having been treated "as a human being."  There may be “essences” of man and woman, but such an essence would be only one factor in a complex person in whom many other factors—nature, nurture, culture unique personality, and individual decisions—make it impossible to indulge in stereotypes.


Objection 6.  For Plato, truth, beauty, and goodness are static, and only the only place for change and growth are on the level of the participant things.  But truth, beauty, and goodness are living and dynamic.  We contribute to the actualization, not just of pre-established potentials, also but to the very evolution of truth, beauty, and goodness themselves.

Reply: There is a contemporary horror of the eternal and unchanging, as though allowing anything important in the universe to be "static" would automatically be repressive of the vital dynamism that we cherish so much.  Whatever growth and dynamism there may be in truth and beauty and goodness, they have an eternal and changeless core, as Plato saw. 


Objection 7.  If we posit a form, humanity, because of our linguistic-observational habit of recognizing the similarity between human beings, shouldn’t we next notice a similarity between the form and the human beings?  If so, then we need to posit a further form, as the formal cause of the similarity between human beings and humanity.  In this way, we can generate an absurd infinite regress of forms.

            Reply: This puzzle arises only through a failure to grasp the purely intelligible (not visible) character of the form.  The similarity of human beings is perceived, visible, noticed “with the eyes.”  Such similarity does not obtain between a human being and the form.  So there is no need to posit a further form.  This problem (called the “third man problem”) and its solution are dialectically presented in Plato’s much misunderstood dialogue, the Parmenides (see the summary to follow).


Plato’s teachings about the forms (eide is the plural of eidos) has two main sides: (1) the epistemological side—whenever we grasp or seek to grasp and articulate whatever is intelligible, we are grasping or seeking to grasp and articulate what may be called an eidos, a “form.”  This is true whether we are talking of the essence of, say, a horse (of which we only have an intuitive idea, not full biological knowledge), or whether we are thinking of motion or size or triangle or justice or beauty.  (2) The metaphysical or ontological dimension of forms: the form is real, not on the model of a perceivable thing in space and time, but real nonetheless.  When we ask about the truth of something, we are asking not merely about what our minds project, but about what is real.  Moreover, the form makes a thing what it is.  Take away the horseness of the horse and all you have left is dog food.  Take away the artistry of the artist and all you have left is self-indulgent display.  Take away the quest for wisdom from the philosopher, and all you have is extreme skepticism or defensive dogmatism.  In this sense, the form is the cause of a thing’s being what it is; whatever characteristics a thing has it has because it participates in forms.

This analysis of what causes a thing to be what it is may seem inadequate; Aristotle supplemented it, drawing on elements that you can find in Plato.  In order to have a full account of something (to stay with examples of perceivable things) you need include four “causes”: (1) the material cause (what is the thing made of, e.g., the particular kind of body of the horse); (2) the formal cause (the form, which specifies limits on the quantities that enter into the constitution of the thing); (3) the efficient cause (the parents of the horse or the creator of the artifact [note: in the Timaeus Plato imagines a Creator who knows the forms and looks upon the eternal patterns and fashions copies in our realm of time and space; but Aristotle’s divine First Cause does nothing similar]); and (4) the final cause, the goal aimed at by the purposive process that brought the thing into being.

            If possible, we would prefer that our lives be based on truth.  Think of the key facts we rely on.  How good is our understanding of those facts?  How much would it help you to understand the network of causes in which the fact has its context?  What is the place of this fact or causal network “in the big picture”?  What about our interpretations of things—the way we are treated, for example?  Questions of truth can be raised on many levels. 

The Phaedo raises issues about the truth of the human being.  Are we beings that can be completely understood by material science?  How far can we go trying to understand ourselves in this way?  Are we beings that are best understood as the products of divine, purposive Mind?  How far can we go trying to explain things this way?  Socrates insists that mere material factors may be part of the story (necessary conditions), but they cannot be the heart of the story.  Socrates remains in prison because he judges that it is right (just) and good to do so.  What is the truth about what it means to be a human being?  How do we see ourselves and others?  Do we see ourselves as capable of attaining knowledge of truth and capable of recognizing beauty and goodness?  Do we take more care for the growth of our soul (psyche) than the satisfaction of the body?  In this life, the mind (often the best translation for psyche) is so entwined with the body.  But psyche is the principle of life (for the ancient Greeks): lose your psyche and you’re dead.  If psyche is essentially bound up with life, then soul is immortal (as a matter of the necessary relation of forms).  So the soul is immortal. 

             Questions tumble out.  What are the problems with this key argument in the Phaedo?  Are there any other reasons to think that there may be life beyond the mortal career?)  Is this even an issue that we can possibly have truth about?  How shall we seek truth in such a question?  If we do not now believe that we know, what shall we do?  Where or to whom shall we turn?  Is there a divine Whom?  Can philosophy clarify that question?  If we affirm the prospect of life after death, does it invigorate our quest for truth, beauty, and goodness?  If we do not affirm the prospect of life after death, what effect does that have upon our higher striving?


For advanced classes, here is further teaching on the forms from Plato's dialogue,  the Parmenides (as interpreted by Mitchell Miller)

            Note: Plato considered more advanced objections to the doctrine of forms in his dialogue the Parmenides.  That dialogue is so difficult to understand, however, that I recommend you read it only with the book by Mitchell H. Miller, Jr., Plato's Parmenides (Princeton University Press and then Pennsylvania State University Press).  One of the main points to be grasped in the early portion of the dialogue is that the forms must not be regarded as quasi-things that exist spatially separate from participant things.  From his book, as I understand it, I take the following. 

            The first portion of the Parmenides implies the following lessons:

There are forms for everything, including dust and mud (130).

The forms are non-spatial (131).

Forms are not thoughts in the mind: thoughts are of what is real—the forms.

Forms are not patterns or models copied by other things (132).

Forms are not simply transcendent, separate from things (133-34).


            The second part of the dialogue imples further lessons:

Hypothesis I:

            Forms do not have the characters of spatio-temporal things.


Hypothesis II:

            The one is not the same as Unity.

            There is an ordered set of categories of basic forms (see below).

            Contrary characters can be predicated of the thing at different times.


            Change is only conceivable by positing atemporal instants of transition in which characters are released/acquired.


Hypothesis III:

            Things between being one and being utterly deprived of [unity] . . . are an affair of peras (limit) limiting plethos (magnitude, fullness, extension), generating a wholel with parts, each of which is also formally specified.


Hypothesis IV:

            If the forms are separate, things are utterly unintelligible.


Hypothesis V:

            The forms commune with one another, in particular, with largeness and smallness, which provide the extension enabling the form to be instantiated in a physical-sensible thing.  (Example: since the Good is beautiful, the Beautiful and the Good are said to commune with each other.)


Hypothesis VI:

            The one [form] must in some sense be, since otherwise nothing could be said of it.


Hypothesis VII:

            Things (which are infinitely divisible) only apparently have character: one, many—contrary characters depending on perspectives.


Hypothesis VIII:

            If forms are utterly not, discourse collapses.


            Now let's comment on this summary a bit, in the light of Miller's last chapter on Hypotheses III-VIII.  I noted in this text the following terms that serve, in different contexts (sometimes where the One is the form, sometimes where the One is the composite thing, and occasionally where the One is the form unity itself): partlessness, integrity, (numerical) singularity, uniqueness, aggregation/sum/heap, composite, wholeness, likeness to itself, sameness with itself.

            Regarding III: The presence of the one form lets “all” stand not merely as a “many” but as a “whole and one” (157e3; M 129).  What is teleion is perfect, finished, in need of nothing further.  The idea or form, then, in some sense perfects or finishes the “many,” transforming it from a mere aggregate to a self-sufficient one” (M129).  Note the overlap of the functions of the form with the functions of the paradigm.

            How does participation work?  Peras (limit) limits plethos—a mere many, lacking any intrinsic enumerability;  connotes both multitude and magnitude (M131); a mass without internal structure or articulation; because it’s characterized as apeira, it’s indeterminate or indefinite both in number and magnitude; cannot be counted except by reference to altogether external standards of measure; not something that, by itself at least, exists; arrived at by dianoetic abstraction (M132); the sheerly material element or medium of things, conceived in its purity as apart from and unspecified by any intelligible structure (any One or form).  It is through partaking of (1) the great and the small and (2) in the One. 

            The one form provides peras, boundary, limit, definiteness.  It “defines the terrain on both sides, differentiating an area into definite regions and relating these to one another within that area as a whole.  Or, considering it from the point of view of the particular regions, each is not only bounded-off, made a distinct entity for the first time; each is also set into relation, as the distinct entity it is, with the other region for the first time.” (M134). 

            “Just how a bulk or extent is structured, how it is articulated into parts, depends upon just what it is the bulk or extent of.  Conversely, this what—the essential or defining character of a thing—calls for a certain definite arrangement of material parts” (M134)  Only through “the form in its immanence” does the plethos become a ‘complete’ or ‘finished’ thing (134).  “The parts have peras ‘in relation to one another,’” and “the whole has peras in relation to its parts” and, further, in relation to other things (134-5).

            In Hypothesis IV, the key teaching is that if composite things are “utterly deprived of the One [form], then they would lack unity in every sense, and plurality, enumerability or number, would not have any discrete characters at all, would not be like or unlike, the same or different, moving or resting, coming into being or perishing, would not be greater, lesser, or equal to one another—or any other characters.  The physical-sensible things—and discourse—would be demolished if there is no participation in the forms.

            For thoroughness of inquiry (no easy declaring victory), we’ll go through the negative possibilities in hypotheses V-VIII—if a One is not.  In retrospect, we note that the conclusion of H I, denying intelligibility to the form, can’t be right.  H V sets out to fix that problem.  To say that ““[a] One is not” presupposes that [the speaker] can distinguish his subject term from its “opposite,” what is “not one”; that is, it presupposes that he can distinguish “the One” from the others.  Thus the One must . . . be knowable, a referent or subject of knowledge, and it must differ . . . from the others.  Moreover, all of this presupposes that it can stand in, or be a referent term for, many relations; otherwise it could hardly be “that” which or “what” is referred to in discourse, and “from which” “the others” are different, and “to which” there belongs a knowledge which, in turn, is “of” or “about it,” and so forth.” (M 142)

            Plato appeals to the way forms can participate in each other (the “communion of the forms”) to develop his continuing account of the participation of the thing in the form.  “The constitutive function of forms for things is impossible without such a communion.  The thing derives its material element, its physical magnitude, from the great and the small; but this element requires determination by the One (the defining form).  Thus, for either the great and the small or the defining form to exercise its constitutive function for the thing, each must combine with the other.  This is not to say, of course, that the defining form gets size, nor that the forms of size are in themselves defined by that form.  Rather they commune so that “the others,” existent things, partaking of the forms in this community, may derive their own proper size and character from them. 

            In the final part of the unfolding of Hypothesis V, Parmenides speaks of the forms as both being “in motion” and not in motion.  What can this mean?  Any properly non-physical motion must belong to the soul.  The soul’s initial grasp of any form will be broad, so that it is necessary to narrow it down, make it more precise, by the method of bifurcatory choices (“motion”) regarding the encompassing forms with which it communes (153).  The forms are what they are in terms of the tree of bifurcations (“movement”—in the mind) in terms of which they are defined.  (Think, for example, of the following logical tree: beings—living or not.  If living, capable of perception and movement or not.  If capable of perception and movement, then either having reason or not.)  At each bifurcation, there is one term that the form is not (while, as the subject, it remains constant (unmoved) as ground for predication. 

            Not only shall we predicate being of the form.  There is also a sense in which the composite, participant thing may be said to be—in that it participates in being. 

            Each form has non-being in the sense of its being different from other forms.  Thus we note that “is” has a simply predicative sense as well as an existential sense (152).

            The primacy of the form with respect to its blendings/communing with/participation in other forms—or knowing—provides an anchor for ontology and epistemology.  The form is not a mere concept in the mind, nor dependent on the mind in any way.  The form is real, and it is up to the mind to approach and to attempt to cognize the form.

            There are no sharp boundaries on a material level.  In order for things to be articulated as individual and different, the forms must determine the limit in the [chthonic] multiplicity of the great and the small (163).

            (Re: VIII) To deny the forms is to deny appearances as well.  What could they be appearances of?