A List of Key Platonist Concepts

Explained Contextually in Relation to Each Other

This essay summarizes the results of discussions of key Plato excerpts given in another essay.

The problem with a great deal of current Plato-interpretation is that it gives insufficient attention the context in which his thought occurs.  After the manner of objective scientific research, it just takes single statements of Plato literally at face value, and asks "Is it true?"  (E.g. Is it true that the Platonic Form of Courage exists?)   Or it assumes that Plato, as one of the key founders of Western philosophy, must have been trying to answer the questions that modern philosophers think all genuine philosophers should be trying to answer.  This approach for the most part results in a rejection of Platonism today, as illustrated in the Appendix below, describing Immanuel Kant's assessment of Plato.

The present critical reconstruction of Plato focuses instead on a more thoroughly contextual interpretation. 

"Contextual interpretation" here means three things:
    1- Plato's key terms and concepts are mutually defining -- each one can only be understood by relating it to other concepts defining the Platonist worldview.
    2- The meaning of the concepts must be limited to what can be rationally supported by the model of Socratic/Platonic reasoning described in earlier essays.
    3- Ideas related to Platonic Forms need to be understood in relation to the function of these Forms in the personal life of the ideal Platonist.  That is, they should not be regarded as an attempt to present an accurate map of objective-reality-as-it-is, but as a "worldview" in terms of which the ideal Platonist defines her "moral identity."  What makes Platonism a good worldview is that it provides an individual with a "transcendent" focus for her ultimate loyalties, a focus deserving of unreserved loyalty because it is transcendent in its Goodness. It does this by correcting the common mistake people make in allowing their worldview to be dominated by the more concrete and tangible realities that dominate the material and social life around them.

A fully contextual interpretation can pay full attention to the particularity of Plato's worldview, without worrying about whether it is the only "universally true" worldview, and also not comparing it to some other worldview which the interpreter regards as the only universally true worldview. (All worldviews are particular, none can be rationally proven to have universal validity.)
    The present essay gives a contextual interpretation of the main Greek words and phrases Plato uses in crucial passages concerning the Forms in his dialogue The Republic, Books 5-7.  Click here for a translation and detailed commentary on the relevant passages.

 

The main terms and concepts related to the Forms that need to be discussed here are:
    -"Always the same" in contrast to "changing."
    -Sense perception (aisthesis) in contrast to "mental understanding" (noesis, gnosis, episteme)
    -"One" vs. "Many"
    -"Appearances" (doxa) contrasted with

  --- "essence" (ousia) and

  --- "being" (einai, on)
    -"Divine" (theios)
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About "always the same," (said of the Forms) in contrast to "changing."

The English phrase "always the same" translates a rather awkward Greek phrase, hōsautōs aei echei.  Hōsautōs is the adverbial form of hōs autos, literally "like (hōs) itself (autos)".  A Platonic Form is something that always (aei) remains "like itself." What would it mean for a concept not to remain "like itself"?  In the context Plato's thought, as a definition of rightness, a phrase like "return to each what belongs to him" does not remain "always like itself," in the sense that following this definition would sometimes result in doing what is right, and sometimes doing what is not right (in the case of the weapons-owner gone insane).  In Plato's words, following this rule would "sometimes mean doing what is right, sometimes doing what is not right."

  Interpreted in this context, "always the same" refers to the ability of the Forms to remain unchanged in the face of Socratic questioning. I might at first think that I believe in always "telling the truth." But when a murderer asks me about the whereabouts of his intended victim, this experience causes me to change my mind, learning that I don't really believe in "telling the truth" as an "unchanging" moral norm. (In Plato's words, following this rule would mean "sometimes acting rightly, sometimes unrightly.")  As two of Socrates' conversation partners complain, their ideas will not "stand still" in the face of Socratic questioning, but keep "moving about" like the fabled mechanical statues of the legendary sculptor Daedelus. Socratic reasoning consists in systematically searching out in advance such contradictions in my thought and experience and trying to resolve them by refining my concepts, so that there will be less need to change my mind in the future. The concept of a Platonic Form is an idealized image of the end product of such questioning and refinement.
    Thus, secondly, "always the same" refers to the ability of Platonic Forms to serve as an always-reliable focus for my unreserved moral commitments and loyalties, an always-reliable guide to personal moral character-development.  This is the function they need to serve in the life of the ideal Platonist. No rule for visible behavior can serve this function, nor can any concrete person or institution, since I can always be faced with individual situations in which it would not be right to follow some such rule or follow the guidance of some particular person or institution.
    (Note that this is completely different from the common association of Plato's "unchanging Forms" with belief in a single set of timeless "eternal truths," valid for all people for all time. Suppose I show that some given definition of "courage," for example, can survive Socratic questioning unchanged. How could I possibly know that no other definition of courage is equally able to survive Socratic questioning unchanged? )
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    Sense-perception (aisthēsis) in contrast to mental understanding (noēsis); "many" particular examples in contrast to "one" concept they all exemplify.
    Plato uses no Greek terms exactly equivalent to the English words "concrete" and "abstract" that I use in my explanations of his thought. Instead he uses two contrasts to get across similar ideas. In relation to the virtue of courage, for example, he speaks of:
    A-Concrete behavior such as courageous actions perceived by "sense-perception," (aisthesis) contrasted with mental understanding (noesis) of the abstract idea of courage, or
    B-"Many" concrete courageous actions, contrasted with "one" abstract idea of courage that they all exemplify.


    With our physical senses we perceive a multiplicity of constantly changing particular concrete things, people, and events. None of these concrete things can serve as a constantly reliable focus for moral commitments or as a norm for self-evaluation. Hence it is a mistake to take this concrete visible world as an evaluative context for defining one's moral identity.
    The same is true of moral rules defined in terms of easily observable external conduct. We can easily observe whether someone is "harming others," or not. But any general rule we formulate in terms of externally visible behavior will always refer to an ambiguous "appearance" of virtue rather than to virtue itself. No matter how sophisticated and complex a rule we formulate on any given topic, a politician or a terrorist wanting to gain people's trust can follow such a rule for egocentric or evil motives. (This doesn't mean we should not have rules, only that we can not expect any rule for external behavior to represent something only and always admirable.)
    And it is not that the reality perceived by the senses is wholly bad, containing nothing good. Plato invites us to conceive of the pure and perfect Form of Beauty as existing in concrete beautiful people. It's just that this pure beauty it exists there "mixed" with other things that are not beautiful. Grasping the pure Form of Beauty requires mentally "separating" pure Beauty itself from everything in a beautiful person that is not beautiful. This "separating," (chorizein in Greek) is the closest equivalent in Plato to the modern philosophical concept of "abstraction."  (The English term "abstract" comes from a Latin equivalent, abstrahere, literally to "pull-out" [trahere=pull, ab=out] i.e. to mentally pull a general concept out of individual concrete examples). 
    This mental separation must ideally be as complete as possible: Perfect Beauty can only be perceived in a concept entirely separated from anything visible or visualizable. The capacity to grasp and feel at home with such separated/"abstract" concepts is often represented in Plato by the Greek term noēsis, which stands in specific contrast to aisthēsis, sense-perception (whence the English "an-aesthesia" making pain non-perceptible). A few other Platonic terms such as logos, "Reason," or gnosis and epistēmē "Knowledge," need to be understood in this same context, referring to the mental capacity to grasp abstract Platonic Forms.
    Perfect virtue-concepts are concepts separated from concrete-visible reality in several senses.
    - First, they are separate in the same sense that any general concept is separate from the concretely existing things exemplifying this concept.  Compare this to the number "two" and the general concept "white." We can see two concretely existing white horses and two white houses. The number "two" and the concept "white" are general concepts that are not concretely existing entities, and are not visible to the senses in the way that two white horses are. One can see white objects, one cannot see the concept "white." Platonic virtue-concepts share this "invisible" character with all general concepts like "white." 

("White" is also a single concept exemplified by many white objects, just as "beauty" is a single concept exemplified by many beautiful things and people. This is the main meaning of Plato's talk about "one and many." The contrast is not between one true concept of beauty and many other false concepts. There might be many different pure and perfect beauty-concepts held by people in many different cultures. Each of these would still be a single concept exemplified by many beautiful things and people.)
    - Secondly, a virtue itself (courage, patience, love, etc), is an internal personality trait, a set of motivations, fundamental attitudes, and mental capacities that have become an habitual part of a person's makeup. Personality traits manifest themselves in visible actions, but they themselves are not directly visible. (A generous person stuck on a desert island and deprived of opportunities for visible generous actions, does not thereby lose the invisible internal virtue of generosity.)  Virtues can only be defined in terms of invisible internal motives, attitudes, and capacities, not in terms of visible behavior.
    - Thirdly, perfect virtue concepts are separate from all concretely existing virtuous people in that no concretely existing person is perfectly and unchangingly generous or courageous in the way that the Platonic Forms of Generosity and Courage are able to represent the pure essence of generosity and courage. Abstract Platonic Forms transcend the capacities of concrete realities in their perfect, "transcendent" Goodness.
    Note that the problem here does not lie in the concrete visible world itself, so that the solution would be to try to literally separate oneself as much as possible from materiality itself, to live as much as possible in a purely "spiritual" world (the tendency of later ascetic versions of Platonism). The problem is rather concrete-mindedness, the habit of thinking only in concrete images (because this comes most easily to most people) and letting oneself be most influenced by concrete reality (because this makes the strongest impression on our senses and emotions). The solution is not literal separation from material reality, but developing a capacity to think in terms of virtue-concepts abstracted from any concrete rules or images of concrete behavior, and taking these as ideals to try to approximate in one's life, and as norms for self-evaluation. The ideal Platonist does not try to literally live in an invisible non-material world. She tries to make her concrete life in the material world participate as closely as possible in the perfection of the invisible/abstract Platonic Forms.

Why is it that abstract virtue-concepts are unchangeable in a way that visible persons, visible conduct, or rules for visualizable conduct, are not unchangeable?

First, it should be noted that concepts themselves, as concepts, are not changeable in the way that concrete entities are changeable.  When a white object changes from being white to being blue, this involves no change at all in the concept "white."  Even if all white objects vanished from existence, causing the concept white to vanish from the minds of subsequent generations, this would involve no change at all in the concept "white."  Members of these subsequent generations wanting to know what we meant by "white" would have to do what they could to discover our concept white.  It is not that "white" is a thing-like entity remaining unchanged ("eternally existing") through time.  Things exist in time and can change through time.  The concepts "time" and "change" simply do not apply to concepts the way they apply to concepts like the concept "white" or the concept "courage."

More importantly for Plato's purposes, abstract definitions of invisible personality traits are able to serve as more unchanging guides to moral improvement, than are rules for visualizable behavior.  There is no rule for visualizable behavior that one can follow and be assured that following this rule will always result in admirably courageous behavior.  "Always stand your ground," or "Always flee," or "Always risk your life" will not work in all situations.  Consider by contrast the following guideline for training yourself to be a more courageous person, "Develop the habit, when faced with danger, of focusing on an assessment of the positive possibilities available in the situation, and what should be your most important priorities in this situation."  Such a habit is itself something internal and invisible, that will manifest itself in very different visible conduct in different situations.  Having this habit is much more "unchangeably" an indication of having admirable courage than is following any rule for visible conduct that one could devise.

("But you can never know that this description of an internal and invisible character trait is absolutely precise, and not in need of further refinement, further 'change' of this kind."  Yes.  Realistically, we need to be satisfied with creating concepts hat we can know to be more unchangeable than others.  "Absolutely final and unchangeable" is an ideal goal we should try to approximate, driving us on to more and more improvement, not an all-or-nothing goal we must either completely achieve or consider all our efforts wasted.)
*****
"Appearances" (doxa) of virtue contrasted with the "essence" (ousia) or "being" (on) of virtue.
    In Plato's dialogues, Socrates sometimes asks others, dokei soi...? "does it seem to you that...?"  Doxa (the noun form of dokei) thus refers to the "seemings" of things. It can thus sometimes refer to a person's public "reputation" for virtue -- because of his visible external behavior he seems to others be an admirable and virtuous person -- he "gives the impression" of being admirable.  But doxa can also refer to the visible behavior itself, in which case it seems best translated as "appearances," or "manifestations." The action of giving someone a present is not caring itself, but is one visible way in which the invisible internal virtue of "being a caring person" can manifest itself. A person whose thought about caring is determined mainly by such external manifestations can be described as "going by appearances," or "judging by appearances." Plato uses the verb doxazein to refer to this "going by appearances."
    A person swayed entirely by beautiful things perceived by the senses is called a "sight-lover" and "sound-lover" (philo-theamones and phil-ēkoos), but also an "appearance-lover" (philo-doxous) -- i.e. he is attracted to these imperfect, externally visible appearances of beauty, rather than to Perfect Beauty grasped by means of an abstract concept. Plato makes up these Greek word-compounds involving philos/love, so that he can contrast appearance-lovers, philo-doxous, with a true philosopher, a philo-sophous, literally a "wisdom-lover."
    But of course Plato's "philosopher" is not just any kind of philosopher, and the wisdom he loves is not just any kind of wisdom. True wisdom consists in knowledge of abstract Platonic Forms, which represent the invisible "Essence" (ousia) or "Being" (on) of virtues, not their outwardly visible appearances (doxa). This knowledge of the invisible essence of virtues is the only true knowledge of virtue, so it deserves the name Knowledge (epistēmē or gnosis), which Plato contrasts with doxazein, "going by appearances."

Doxa is often translated as "belief" or "opinion," as opposed to "knowledge."  To the ears of modern philosophers, this makes it sound like a distinction referring to differences in the basis for people's views about goodness.  On this view, "opinions" and "beliefs" are views which have a flimsy foundation in perceptions too colored by unreliable "individual," "subjective," and "culturally conditioned" factors.  Some view about goodness counts as genuine "Knowledge" only if it is absolutely certain because it is based completely on what are known to be purely objective facts, or based on self-evident "necessary truths."   But these latter criteria are unknown to Plato.  Personal perceptions of goodness -- "subjective" and "culturally conditioned" as they are -- are the only real basis for his moral arguments.  So for him episteme/Knowledge of courage is not distinguished because it has some basis more certain than subjective perceptions.  True Platonic "Knowledge" is distinguished not by its basis but by its object, what it knows.  True Platonic Knowledge of Courage is very precise knowledge of the essence (ousia) of what it is that makes admirable courage admirable.   Platonic essences are always abstract, not directly visible to the senses, and this is what makes a mental grasp of the essence of Courage different from grasping through the senses only the visible doxa/"appearances" of courage witnessed in visible courageous behavior.



About "essence" (ousia).
    Since it needs to serve for self-evaluation, the key characteristic defining what a virtue's "essence" consist in, is that this essence will be something purely and always admirable.

So one cannot simply ask, for example, "What is courage?" Asking the question this way could simply mean: Give a dictionary definition of courage, describing what people usually mean by the word courage. Clearly this would not serve Plato's purposes, because the whole endeavor of his thought assumes that common ideas about virtues are inadequate to use as norms for self-evaluation.
    One must ask rather about admirable courage -- what is it that differentiates admirable courage (courage as a "virtue") from mere foolhardiness, which has some of the "appearances" of courage, but is not admirable? The essence of courage is what it is that makes admirable courage admirable. If one were able to articulate in a very precise way what it is that makes admirable courage admirable, then one would have a concept representing something only and always admirable.
    For example, when Laches tried to articulate his sense of what courage is by saying that courage is "standing at one's post and not running away," this was an imprecise articulation, failing to get at the "essence" of courage. "Standing at one's post" is ambiguous rather than precise, because the action of standing at one's post sometimes manifests admirable courage, and sometimes foolish stubbornness (when it would be wiser to retreat and regroup). If Laches were able to articulate in a very precise way exactly what he admired when he saw a solider admirably standing at his post, he would have isolated the essence of admirable courage in an exact and unambiguous way, isolated from ambiguous appearances that frequently manifest or accompany this essence, but are not the essence itself. He would know that he was coming closer and closer to isolating this exact essence in a concept when it became harder and harder to uncover ambiguities in this concept, ways in which it could be interpreted so as to apply to instances that are not admirable.

Note that, in the present reconstruction, it is not quite accurate to speak of "the essence" of courage, implying that there is only one concept of courage that is always and only admirable.   Socratic reasoning cannot show that some particular concept of courage is the only valid Platonic Form of courage, and that there can be no others.  So it is more accurate to say that Socratic reasoning about courage aims at discovering "an essence" of courage, not "the essence" of courage.

About "Being" (einai, on)
    Used in relation to the Forms, "Being" (einai or on) does not mean "existing" in contrast to not-existing. The contrast is rather between Being and Appearance, i.e. the invisible reality of virtue, grasped by noesis through abstract Forms, contrasted with its externally visible appearances (doxa) grasped by the senses (aisthesis).
    The primary function of the Forms is to serve as a evaluative context in relation to which the ideal Platonist defines her moral identity. They are the prime components of the worldview of the Platonist, constituting the prime "reality" she lives in, in terms of which she defines herself. It is in this sense that they are what is "most real" to the Platonist -- they are in Plato's words what is most "really real" (ontōs on) for her.
    This is probably a deliberate contrast with what most other people consider "really real," i.e. concrete objects and events visible in the material world surrounding us. Not only are such visible things and events the paradigm case of what most people consider "objective" reality, they also dominate the worldview of most people, serving as the prime evaluative context in which they define who they are. Today, we tell people who seem overly idealistic to "get real," or "face the real world," using "real" to refer to the forces that actually prevail in the very imperfect material and social world, which we contrast with the aspirations of idealists.
    Plato wants to replace this concrete "real world" with another, the world of the Forms, which the ideal Platonist regards as "more real," in the sense that it deserves to be taken more seriously than the concrete world we see around us.
    Since the Forms are what are "most real," and have most "being" in this sense, Plato sometimes refers to them simply as "the Beings." In contrast to the ever-shifting relation between concrete reality and true goodness, the Forms are unchanging in their ability to represent true goodness, and it is in this sense that they can also be described as "always being" (aei on), i.e. unchangingly and invariably representing the full being of true Goodness.
*****
    This contextual understanding of ousia and on, "essence" and "being," is perhaps the most important way in which the present critical reconstruction of Plato's thought departs from Plato-interpretations more common in modern philosophy, interpretations which are also responsible for the rejection of Platonism today.
    - In these common interpretations, "essence" is connected to the doctrine of "fixed essences" -- the doctrine that there is only one specific set of categories capable of representing reality as it is, and everyone everywhere throughout all time must think in these categories if they wish to have a true grasp of reality. But no one today knows a mode of reasoning capable of showing that some particular set of concepts or categories has this universally obligatory character. Meanwhile, holding a theory like this has become one of the main obstacles to full acceptance of cultural diversity and historical change in cultures. Consequently when Plato's talk about the unchanging "essence" of virtues is interpreted as a reference to fixed essences of this kind, this has become a reason for rejecting Platonism itself.
    The present critical reconstruction of Plato avoids this problem by restricting the meaning of "unchanging" and "essence" to what can be rationally shown by Socratic reasoning, and what needs to be shown to give rational support to the Platonist way of life for individuals. Limited in this way, "unchanging" refers only to the ability of a given virtue-concept to represent something unchangingly admirable for a single, individual Platonist. It does not exclude there being innumerable other virtue-concepts able to represent something unchangeably admirable.
    Think of it this way: When Steve changes his clothes at the end of the day, we don't say that Steve's clothes have changed, but that Steve has changed his clothes. Think of Platonic Forms as a potentially very large closet full of very many unchangingly excellent virtue-Forms. Suppose Steve as a Platonist at age twenty took ten of these unchanging Forms to model his character on. At age sixty he took ten completely different unchanging Forms to model his character on. There has been no change in the Forms at all, they are all what they have always been. It is Steve who has changed the Forms he takes as the focus for his ultimate moral commitments. This can be equally true on a larger scale of historical change and cultural diversity. When modern Europeans find most attractive a set of virtues completely different from those virtues most attractive to their Medieval ancestors, this is not because the virtues or virtue-concepts themselves have changed. Europeans have changed virtues, as Steve changed his clothes.
    Similarly, when Plato speaks of the Forms as aei on, "always being," many take this as a belief that the Forms are "eternally existing": Alongside the visible material universe full of things constantly coming into being and passing away, there exists an entirely separate, non-material parallel universe in which there exist thing-like entities called "Forms" that do not come into being or pass away, but exist eternally.
    Again, neither Plato nor anyone else offers rational evidence supporting belief in the objective, literal existence of such eternally existing entities in an entirely separate parallel universe. So when Plato is understood in this way, this leads to a rejection of Platonism as groundless speculation.
    The present reconstruction of Plato avoids this problem by restricting the meaning of aei on "always being." On this interpretation, what is important about virtue-Forms for the life of the Platonist, and what can be shown about them by Socratic reasoning, is that they always and unchangingly have the full and pure "being" of goodness. The contrast is with visible realities, and rules for visible conduct, that are only partially and changeably good.
    The Forms representing pure Goodness do not have a kind of being completely different from the goodness that we perceive in concrete people and their behavior. It is this same goodness, that has only been mentally separated from other "appearances" that accompany it in these people and behavior.
*****
"Divine" (theios)
    For the ideal Platonist, Form-centered philosophy serves as a substitute for popular religion.
    Athenian popular religion in Plato's time was polytheistic, and moral rightness was not a salient characteristic of the many gods and goddesses that figured in this religion, as it is in Judeo-Christian-Islamic monotheism. Greek usage of the word "divine" (theios) or "godlike" (theio-keilon) was also more relaxed than it is in these monotheistic religions. Monotheists generally make a very strict division between God and humans, so to call something "divine" is to associate it with this one God. Greeks could speak more easily of a poem or statue as something "divine," because of awesome beauty, not necessarily meaning by this that it came from the one God instead of from a human artist.
    Plato criticized the gods and goddesses of Athenian popular religion because the myths and legends concerning these divine beings did not always teach good moral lessons. Instead, he spoke of his perfect virtue-Forms as "divine," and spoke of the project of forming one's character on the model of these Forms as "becoming god-like, as much as is possible for humans."
    It is worth quoting here one passage from Plato's Theaetetus illustrating this usage.

Evils can never be done away with [in this world]... they [do not] have any place in the divine world, but they must needs haunt this region of our mortal nature. That is why we should make all speed to take flight from this world to the other, and that means becoming like the divine so far as we can, and that again is to become righteous with the help of wisdom.... In the divine there is no shadow of unrighteousness, only the perfection of righteousness. And nothing is more like the divine than any one of us who becomes as righteous as possible. (176a-c.)

Although Plato does not explicitly mention the Forms in this passage, his mention of taking flight to this other world of pure Rightness by becoming as righteous as possible indicates that this is what he has in mind. Plato's substitution of a divine realm of morally perfect Forms for the world of the Greek gods and goddesses, gives the Platonist a focus for his ultimate loyalties that is both more rational and more "transcendent," in the moral sense of transcendent Goodness.
    In subsequent essays I will follow Plato in this, for the sake of a fully rational treatment of the question of what finally matters. Views of what finally matters can be rationally supported to the extent that they give a person a focus for her ultimate loyalties that is transcendent in its Goodness. To the extent that "God" or divinity is the name for the what a person takes to be the highest moral authority, from a rational point of view something deserves to be associated with divinity to the extent that it can be shown rationally to represent something purely, only, and always Good.

(An interesting historical footnote: At a later period, Christian Platonists interpreted Platonic Forms as "Ideas in the mind of God," which he used as models for creating the world.)


Appendix: Plato as failed metaphysician.

Works on Plato today routinely refer to the Form theory as part of "Plato's Metaphysics," as though it were obvious that he devised his Form theory as a contribution to a discipline familiar to modern philosophers called Metaphysics. The present treatment of Plato departs strongly from this interpretive tradition, and this deserves some comments here.
    Plato does not use any Greek word corresponding to the word "metaphysics." Aristotle, Plato's pupil, did not use the word either, but wrote a book that was later called by his editors "The Metaphysics" (possibly just because it came after, or should be studied after, his book on "physics." "After" is one meaning of the Greek word meta).
    The term "Metaphysics" in modern times has been used in various senses. In general it designates knowledge of entities that are not observable in the way things and forces in the material world are observable. The existence of such entities, largely taken for granted in premodern times, has become problematic in modern times, largely due to the influence of the physical sciences with their exact methods of verifying the objective existence of the entities and forces that figure in scientific explanations. Hence speaking of "Plato's Metaphysics" automatically puts his thought in this problematic category.
    The work of Immanuel Kant marks a watershed in the history of metaphysics, because he insisted that all supposedly metaphysical knowledge which could not be verified by strictly rational methods should be discarded. There seemed to him to be really only two kinds of truths verifiable by reason, (a) empirical facts about the material world verifiable by scientific methods, and (b) "necessary truths" such as truths in mathematics like 2 + 2 = 4. "Necessary truths" are those that are self-evident. For anyone who understands the meaning of the numbers "2" and "4," and the meaning of the mathematical signs "+" and "=," the assertion "2 + 2 = 4" will be self-evident and undeniable.
    It is obvious, of course, that if Plato's Form theory is interpreted as "metaphysics, it fails Kant's two tests of rationally verifiable knowledge. The Forms are clearly not entities like water and gravity that can be investigated by methods of the physical sciences. And far from being clear and self-evident, truths about the Forms are very difficult to understand, and in fact cannot be conveyed from one person to another. Plato never tries to show that the Form of Courage or of Rightness consist in self-evident "necessary truths" like the truth that 2 + 2 = 4.
    Despite this, Kant insists on treating Plato's thought as an attempt at metaphysics. In some ways Plato serves for Kant as a paradigm case of the groundless metaphysical speculation that Kant thinks was all too prevalent before his own attempt at "critical philosophy." This tradition in Plato-interpretation continues to today, on the one hand assuming that Plato was an aspiring metaphysician, but on the other hand attributing to him a metaphysics which has no rational basis.
    In his fundamental critique of traditional metaphysics in his Critique of Pure Reason, Kant compares Plato to a flying dove. The dove sees that friction with the air is impeding his flight, so he imagines that if he flies up higher and higher where there is no air, he will be able to fly much more easily. The moral: Plato saw that the necessity of finding rational support for his beliefs was an obstacle to holding the idealistic and otherworldly beliefs he wished for, so he decided to "fly higher" to develop knowledge unrestricted by the need for rational evidence. But of course just as the high-flying dove lacked air to support his flight, Plato also left the realm where his knowledge could be supported by rational evidence.
    Here is what Kant says:

The light dove, piercing in her easy fight the air and perceiving its resistance, imagines that flight would be easier still in empty space. It was thus that Plato left the world of sense, as opposing so many hindrances to our understanding, and ventured beyond on the wings of his ideas into the empty space of pure understanding. He did not perceive that he was making no progress by these endeavors, because he had no resistance as a fulcrum on which to rest or to apply his powers, in order to cause the understanding to advance.
It is indeed a very common fate of human reason first of all to finish its speculative edifice as soon as possible, and then only to enquire whether the foundation be sure. Then all sorts of excuses are made in order to assure us as to its solidity, or to decline altogether such a late and dangerous inquiry. (I. Kant, Critique of Pure Reason. tr. Max Mueller. New York: Doubleday. 1966, p. 6.)

Translation: Kant assumes that Plato was trying to do the same thing that Enlightenment philosophers like himself were trying to do, discovering the single true set of moral norms valid for all people for all time. Like many Enlightenment philosophers, Plato looked for such norms in the concepts of "pure understanding," i.e. truths known to pure reason independently of all sense-perceptions. Kant thinks that he has discovered a rational method for coming to know such truths: Truths of pure reason are "necessary truths," truths so self-evident that no rational person would ever doubt them. Kant recognizes that Plato never bases any arguments on an appeal to such "necessary truths," and that indeed it is exceedingly implausible that Platonic virtue-Forms constitute such necessary truths, or that they could be known in this particular way. Kant's conclusion: Plato was trying to do the same thing that Kant was doing, but unlike Kant, Plato did not really know how to do it. Plato realized that appeals to actual evidence could only get in his way, so his thought took flight to heights where no evidence would resist his flight, but no evidence would support his beliefs either.
    (Kant's picture of Plato does find some support in some of Plato's writings. For example, Phaedo 73-76 is one passage where Plato most clearly asserts that Forms can be known by reason apart from the senses. But this passage has nothing to do with any attempt to actually discover "necessary truths" known a priori by pure reason, and indeed provides no method whatsoever by which a person could actually use reason alone to arrive at a knowledge of the Forms.  Plato's purpose in this passage is not to provide any epistemology for knowledge of the Forms. It is rather to enlist his Form theory in support of Pythagorean beliefs in the preexistence and immortality of the soul.  So what Plato means in by "reason alone" in this passage has nothing to do with Kant's "pure reason." It is represented rather by a disembodied mind existing separate from the body, either before or after this earthly life. This is hardly a basis for a rational method or epistemology enabling a living person to arrive at knowledge of the Forms.  Plato's beliefs in the pre-existence and immortality of the soul are parts of Plato's building that have no solid rational foundation, so I ignore them in the present critical reconstruction.)

I fully agree with Kant that Plato's writings teach us no rational method capable of supporting any supposed "Platonist Metaphysics," as the term "metaphysics" subsequently came to be understood in philosophical circles.  Another essay commenting on Plato's writings argues that careful attention to context shows that it is unlikely Plato ever claimed to be teaching "metaphysical truths" as Kant understood them.  But this does not crucially matter.  If Plato made metaphysical claims that go beyond anything he had rational support for, this is a foundationless part of the Platonic building we must let fall, but not let it bring down the entire building down with it.  Contrary to Kant, the validity of the Platonist otherworldly worldview does not depend on the claim that virtue-Forms are metaphysical truths.

*****

A final note on "necessary" truths: For centuries, Euclidean geometry was regarded as the paradigm of an Absolutely Certain and Universal science, which had shown itself to be the one and only true geometry.  This is because it rests on five "self-evident" axioms, and a large set of theorems that follow by strict logical deductions from these five axioms.  This claim to be the one and only true geometry turned out to be based on a confusion between (1) claiming that some truths are a "necessary" truths because they are self-evident, and (2) claiming that Euclid's five axioms are the one necessary choice of axioms that everyone must use as a basis for a system of geometry.  The reason this is a confusion: Knowing that some set of truths (like Euclid's five axioms) is self-evident is different from knowing that there are no other truths that are equally self-evident.  Morris Kline's history of mathematics, entitled Mathematics: The Loss of Certainty is partly the history of the loss of certainty that there is one and only one true geometry, due to the development of non-Euclidean geometries.  This is due to the discovery that changing the definitions of some concepts in geometry will yield a different set of fundamental axioms that are equally self-evident, and that can provide a basis for an entirely different system of geometry.  This does not deny that Euclid's axioms are self-evidently true, it just denies that these are the only axioms that are self-evidently true.

This does not result in complete "relativism" in mathematics, where truth in geometry consists in whatever anyone arbitrarily declares to be true.  It results rather in something like critical pluralism in mathematics: There are potentially many logically consistent mathematical systems, but not just any mathematical system is logically consistent.  This is what I claim for Platonic virtue-Forms.

 

 

 

Some possible topics:

Pick out one or more of the key Platonic concepts treated above, and discuss how they are related to central themes in the first essay on Plato's "otherworldly" worldview.

The discussions above are intended as an example of a "critical reconstruction" of Plato's worldview, limiting the meaning of his key terms to what can be supported by the model of Socratic reasoning described in an earlier essay.  Discuss their relation to Socratic reasoning, and contrast this with the interpretation of these terms that would result from a more literal-minded interpretation, taking these terms at face-value, unrelated to Socratic reasoning, or interpreting them in the context of modern philosophical concerns, aims, and categories.