Chapter 18 Chapter 15 Theory of Ideas

The middle part of the "Nation", that is, from the second half of the fifth volume to the end of the seventh volume, mainly discusses purely philosophical issues as opposed to political science.These questions are posed in a rather abrupt discourse: Unless philosophers are kings, or the kings and princes of this world have the spirit and power of philosophy, make political greatness and wisdom one, and make the mediocre and cast aside; otherwise the city would never be safe from calamity--nor, I believe, even the whole of mankind,--only then would this nation of ours find life and The possibility of seeing the light of day.If this is the case, then we must decide what constitutes a philosopher and what we call "philosophy."The ensuing discussion is the best-known part of The Nation, and perhaps the most influential.There are parts of it of extraordinary prose beauty; the reader can disagree with what he has to say, as I do, but cannot help being moved by it.

Plato's philosophy is based on the distinction between reality and appearance, which was first formulated by Parmenides; throughout the discussion we are now dealing with, the Parmenidean phrase and argument.There is, however, a religious flavor to the reality he speaks of, which is more Pythagorean than Parmenidean: and there is a great deal of mathematics and music in it, and it can be directly Dating back to the disciples of Pythagoras.The logic of Parmenides combined with the otherworldly ideas of the Pythagoreans and the Orphists produced a doctrine which was supposed to satisfy both the intellect and the religious sentiment; the result was a very powerful The synthesis of it has influenced in various forms most of the great philosophers up to Hegel, including Hegel himself.But it wasn't just philosophers who were influenced by Plato.Why did the Puritans object to music, painting, and the red tape of the Catholic Church?You can find the answer in Book Ten of The Nation.Why do schools force children to learn arithmetic?The reason is written in the seventh volume of the "Nation".

The following paragraphs summarize Plato's theory of ideas. Our question is: what is a philosopher?The first answer is consistent with the etymology: namely, a philosopher is a man who loves wisdom.But this is not the same thing as being an intellect in the sense that a curious person may also be said to be an intellect; vulgar curiosity does not make a philosopher.Therefore, this definition should be corrected as: A philosopher is a person who loves "insight into the truth", but what is this insight? Suppose a man loves beautiful things, and he resolves to see all new tragedies, to see all new pictures, and to hear all new music.Such a person is not a philosopher, for he only loves beautiful things, whereas a philosopher loves beauty in itself.He who loves only beautiful things is dreaming, and he who knows absolute beauty is awake; the former has mere opinion, the latter knowledge.

What is the difference between "knowledge" and "opinion"?A man has knowledge, that is, he has knowledge of something, that is, of something that exists; for a thing that is not is not a thing (this brings us back to Parmenides) .Knowledge is therefore infallible, because it is logically impossible for knowledge to err.But opinions can be wrong.And how is this possible?An opinion cannot be an opinion about something that does not exist, because that is impossible; nor can an opinion be an opinion about something that exists, because then it would be knowledge.Opinions must therefore be opinions about what is and is not.

But how is this possible?The answer is: particular things always have opposite properties: beautiful things are also ugly in some ways; just things are also unjust in some ways, and so on.All individual sensible objects, so Plato says, are of this contradictory quality; they are therefore intermediate between being and non-existing, and therefore fit as objects of opinion rather than of knowledge. "But those who see absolute eternity and immutability may be said to have knowledge, and not mere opinions." Thus we arrive at the conclusion that opinions belong to the world touched by the senses, and Knowledge belongs to the supersensible, eternal world; opinion, for example, concerns separate beautiful things, but knowledge concerns beauty itself.The only argument advanced here is that it is contradictory to suppose that a thing can be both beautiful and unbeautiful, or just and unjust; and yet individual things seem to combine these contradictions. characteristics.So individual things are unreal.Heraclitus once said: "We both step and do not step into the same river; we are and we are not"; combine this with Parmenides and we arrive at Plato's result.

However, there are also certain important things in Plato's theory that cannot be derived from his predecessors, that is, the theory of "ideas" or "forms".This theory is part logical and part metaphysical.The logical part deals with the meaning of words in general.There are many individual animals to whom we can truly say "this is a cat."What do we mean by the word "cat"?Obviously that's something different for every individual cat.An animal is a cat, it seems, because it shares the general quality common to all cats.Language would be impossible without a generic word like "cat," so these words are obviously not meaningless.But if the word "cat" means anything, it means not this cat or that cat, but some general felineness.This feline nature is neither born with the birth of the individual cat, nor does it die with the individual cat when it dies.In fact, it has no location in space and time, it is "eternal".This is the logical part of the doctrine.The arguments in favor of it (whether ultimately valid or not) are strong and have nothing to do with the metaphysical part of the doctrine.According to the metaphysical part of this doctrine, the word "cat" signifies some ideal cat, the only "cat" created by God.Individual cats share in the quality of "cat", but are somewhat incomplete; and it is because of this incompleteness that there are many cats. "Cats" are real; individual cats are mere phenomena.

In a preface to the condemnation of the painter in the last volume of the Nation, the doctrine of the Idea or Form is very clearly stated.Here Plato explained that where several individuals share a common name, they share a common "idea" or "form".For example, although there are many beds, there is only one "idea" or "form" of a bed.Just as the bed reflected in the mirror is only a phenomenon and not a reality, so the different beds are not real, but just copies of the "idea"; the "idea" is a real bed, and it is created by God .We can have knowledge about the one bed created by God, but we can only have opinions about the many beds made by the carpenters.The philosopher is thus interested in only one ideal bed, and not in the many beds found in the world of sense.He has a certain degree of indifference to everyday worldly things: "How can a man who has a brilliant mind and is an observer of all times and all existence think much about life in this world?" A young man who can be a philosopher, Among his companions, he will be extraordinarily upright and elegant, devoted to learning, with a good memory and a naturally harmonious mind.Such a man will be educated to be a philosopher and defender of the country.

At this point, Adaimantus intervened in protest.He said that when he wanted to argue with Socrates, he felt that he was always led astray by Socrates step by step until his original ideas were all turned upside down.But no matter what Socrates says, everyone can see that the situation is that all people who are devoted to philosophy will become monsters, let alone become outright rogues; To be rendered useless by philosophy. Socrates admits that this is true in the existing world, but insists that it can only be blamed on other people, not on philosophers; in an intelligent society, philosophers would not look stupid and only among the foolish is the wise considered to be lacking in wisdom.

What should we do in this dilemma?Our ideal country can have two ways of founding: one is that philosophers become rulers, and the other is that rulers become philosophers.As a start, the former approach seems impossible.For philosophers are not welcome in an unphilosophized city-state.But a born prince can be... a philosopher, and "one is enough; if only one man can make a city obey his will, then he can realize the ideal so incredible for the world." regime".Plato hoped to find such a prince in the tyrant of Syracuse, Dionysius the Younger, but the young prince turned out to be a great disappointment.In Books VI and VII of the State, Plato deals with two questions: first, what is philosophy, and second, how can a young man or woman of suitable character be educated to be a philosopher? Home?

For Plato, philosophy is an insight, an "insight into truth".It is not purely intellectual; it is not merely wisdom but love-wisdom.Spinoza's "intellectual love of God" is roughly the same close union of thought and feeling.Everyone who has done any kind of creative work has, to a greater or lesser degree, experienced a state of mind in which, after long labor, truth or beauty appears, or seems to appear, in In a sudden burst of glory—it could be about a small thing, or it could be about the universe.The experience is very convincing for a moment; it may be doubted afterwards, but it is completely convincing at the time.I think that in art, in science, in literature, and in philosophy, most of the best creative work is the result of such a moment.Whether it has come to others as it has to me personally, I am not sure.For my part, I found that when I wanted to write a book on a subject, I had to immerse myself in details until all the parts of the subject were thoroughly familiar; If so, I shall see that the parts are properly connected with each other to form a whole.From then on, I just have to write down what I see.The closest analogy is to walk over a mountain in fog until every road, ridge, and valley is well known, and then to see the whole of the mountain clearly and clearly from a distance in broad daylight. Mountain.This experience, which I believe is necessary to good creative work, is not sufficient; the subjective certainty it brings can indeed be fatally misleading.William James has described the experience of a man who has learned the secrets of the universe as soon as he has been exposed to it, but has forgotten it when he wakes up.Finally, with great efforts, he wrote down the secret while seeing that the scene had not disappeared.When he was fully awake, he hurried to see what he had written."The whole thing smells like oil," he wrote.What appears to be a sudden insight is likely to be misleading, and must be strictly examined when the divine intoxication is over.

When Plato wrote his State, he relied entirely on the spectacle he saw, but in order to convey its character to his readers, his vision finally needed the help of a metaphor, which is The parable of the cave.To get to this point, he employs various preparatory discussions in order to make the reader aware of the necessity of the world of ideas. First, he distinguished the intellectual world from the sensory world; then he divided the intellect and the sense-perception into two.The two senses-perceptions, we need not worry about; the two intellects are respectively called "reason" and "understanding."Of the two, reason is the higher; it deals only with pure ideas, and its method is dialectical.Understanding is the kind of intellect used in mathematics, which is inferior to reason in that it uses assumptions it cannot test by itself.For example in geometry we say: "Suppose ABC is a rectilinear triangle".It would be out of order to ask that ABC is actually. is not. is. a rectilinear triangle; straight line.Thus mathematics can never tell us what there actually is, but only what there would be if...There are no straight lines in the sensory world, so if mathematics is to have more than supposed truth, we must find evidence for the existence of supersensory straight lines in a supersensory world.Understanding cannot do this, but according to Plato, reason can.Reason proves that there is a rectilinear triangle in the sky, about which geometrical propositions we can affirm absolutely, not hypothetically.On this point one difficulty does not seem to have escaped Plato's attention, and is also evident to modern idealist philosophers.We have seen that "God" created only a bed, so we can naturally suppose that he created only a straight line.But if there is a triangle in the sky, then he must have created at least three straight lines.The objects of geometry, though only ideals, must exist in many instances; we must have two. Likelihood of circle intersecting, etc.This suggests that in Plato's theory, geometry should not be able to reach the ultimate truth, and should be dismissed as only a part of the study of phenomena.We can skip this point, however, because Plato's answer on this point is ambiguous. Plato tried to use visual analogies to illustrate the difference between clear intellectual insight and chaotic sensory-perceptual insight.He said that sight was different from the other senses because it required not only eyes and objects but also light.We can see clearly the objects illuminated by the sun; we can see very vaguely in the twilight, and we can't see anything in the dark.The world of ideas is what we see when the sun illuminates objects; the world of flow is a blurry world.The eye may be likened to the soul, and the sun as the source of light may be likened to truth or goodness. The soul is like the eye: when it beholds what is illuminated by truth and being, it sees them, understands them, and shines with reason; At this time, it can only have opinions and it is still flickering. First there is this opinion, and then there is another opinion, as if it is irrational. . . . That which gives truth to what is known, and cognition to him who knows, is what I would have you call the Idea of ​​the Good, and which you will also consider the cause of knowledge. This leads to the famous parable of the cave, which says that those who lack philosophy can be likened to prisoners in a cave, who can only look in one direction because they are locked; their Behind them was a fire, and in front of them was a wall.There was nothing between them and the wall; all they saw were the shadows of themselves and of things behind them, which had been thrown onto the wall by the firelight.They inevitably regard these shadows as real, without any idea of ​​what caused them.At last a man escapes from the cave and comes into broad daylight. He sees the real thing for the first time, and realizes that he has been deceived so far by images.If he were a philosopher fit to be a defender, he would feel his duty to go back to the cave again, to his former fellow prisoners, to teach them the truth, to show them what came out. the way.But he had difficulty persuading them, for he could not see the shadows as clearly as others when he was out of the sunlight, and to them he seemed even more foolish than before he escaped. "I say, let me now use a metaphor to show how far our nature can understand or be confused:--Look! There are many people living in a subterranean cave, and this cave has a small opening for light. Go into the cave; they have been in it since they were children, and their legs and necks were chained so that they could not move; they could only look ahead, and the chains kept their heads from turning. There was a pile of The fire was burning blazingly in the distance, and between the fire and the prisoners there was a high passage; if you looked over, you would see a low wall built along this passage, as if in a puppet show A curtain is set up in front of them by the people who live there, and puppets are to be performed on this curtain. "I saw it. "I said again, do you see many people coming and going on the wall, carrying various utensils on their backs, and various shapes and images of animals made of wood, stone, and various materials appear on this wall? Among them Some people are talking, some people are silent." You pointed out to me a strange image, they are all strange-looking prisoners. "I replied that it was like ourselves, they only saw their own shadows or other people's shadows, which were cast by the fire on the wall opposite the cave". The place of the good in Plato's philosophy is very special.He said that both science and truth are similar to good, but good has a higher status. "Goodness is not the essence, and it is far higher than the essence in terms of dignity and power." Dialectics leads to the goal of the rational world, that is, the perception of absolute goodness.It is by virtue of the good that dialectics does not have to rely on the assumptions of mathematicians.The underlying assumption here is that reality, as opposed to appearance, is the absolute and perfect good; therefore to know the good is to know reality.In the whole of Plato's philosophy, as in Pythagoreanism, there is the same mixture of intellect and mysticism, but at the final peak it is mysticism which clearly prevails. Plato's doctrine of ideas contains many obvious errors.But despite these errors, it marks a very important advance in philosophy, because it is the first theory to address the problem of universals, which has since survived in various forms to the present day.All beginnings are rough, but we should not ignore their creativity.Even with all the necessary corrections, something in Plato's words remains to be preserved.The absolute minimum that is to be preserved (even from the most hostile to Plato point of view) is that we cannot express ourselves in a language composed entirely of proper nouns, but must use some General words such as "person", "dog" and "cat"; or if these words are not used, some relative words should be used, such as "similar to", "before" and so on.These words are not meaningless sounds; but it is difficult to see how they could be meaningful if the world were all composed of the individual things to which those proper nouns refer.Although there are ways around this argument, it nonetheless presents an ostensible case in favor of universals.I'll tentatively admit that it works to some extent.But even if it is admitted in this way, the rest of what Plato said still cannot be derived.The first is Plato's total ignorance of the grammar of philosophy.I can say "Socrates is human", "Plato is human", etc.The word "human" may be held to have exactly the same meaning in these statements.But whatever its meaning is, its meaning always refers to something different from Socrates, Plato, or any other individual who constitutes a human being. "Human" is an adjective; it would be meaningless to say "human is human."The mistake Plato makes is akin to saying "what is human is human".He thinks that beauty is beautiful; he thinks that the universal of "man" is the name of the type of man created by God, and that actual man is an imperfect and more or less unreal copy of this type of man.He completely fails to realize how great a gulf there is between the universal and the individual; his "ideas" are really just other individuals who are ethically and aesthetically superior to the ordinary.Later on he himself began to see this difficulty, as he did in the Parmenides, which contains the most self-criticism of a philosopher in history. Notable precedent. The "Parmenides" is said to be narrated by Antiphon (Plato's half-brother), only Antiphon remembers this conversation, but he only likes horses at this time.They found him carrying a harness, and with great difficulty persuaded him to relate the famous discussion of Parmenides, Zeno, and Socrates.It is said that when this happened, Parmenides was old (about sixty-five), Zeno was middle-aged (about forty), and Socrates was very young.Socrates elucidated the theory of ideas, and he affirmed that there were ideas of resemblance, justice, beauty, and goodness; he was not sure whether there was an idea of ​​man; That statement,-- However, he also said that sometimes he thinks that nothing is without ideas.He shied away from this view for fear of being drawn into the abyss of a never-ending idle debate. "Yes, Socrates," said Parmenides; it is because you are young. If I am not wrong, one day philosophy will take hold of you more firmly, and then you will not despise even the most lowly things." Socrates agreed that, in his opinion, "there are certain ideas which are shared by all other things, and from which things get their names; for example the like are like because they share similarity; great things are great because they share greatness; just and beautiful things are just and beautiful because they share justice and beauty.” Parmenides goes on to list many difficulties. (1) Does the individual share the whole idea, or only a part of it?Either way, there can be arguments against it.If the former, a thing must exist in many places at once; This is ridiculous. (2) When an individual shares an idea, the individual and the idea are the same; so there must be another idea which contains both the individual and the original idea.Then there must be another Idea that includes this individual and these two Ideas, and so on to infinity.Thus each Idea becomes not just one, but an infinite series of Ideas. (This is the same as Aristotle's argument about the "third man.") (3) Socrates suggests that ideas may be just thoughts; but Parmenides points out that thoughts must be about. of something. (4) For the reasons given in (2) above, ideas cannot resemble the individuals who share them. (5) If there is any idea, it must not be known to us, because our knowledge is not absolute. (6) If God's knowledge is absolute, he cannot know us, and therefore cannot rule over us. Idealism was not completely abandoned, however.Without ideas, Socrates said, the mind has nothing to base itself on, thus destroying the reasoning process.Parmenides told him that his difficulties arose from lack of previous training; but never came to any definite conclusions. I don't think Plato's logical objections to the reality of sensible individuals stand up to scrutiny; for example, he says that everything beautiful is also ugly in some respects, that everything that is multiplied is half, etc.Yet when we say that a work of art is beautiful in some respects and ugly in others, analysis always enables us to say (at least in theory): "This part or aspect is beautiful." , and which part or aspect is ugly".As for "double" and "half," these are only relative terms; there is no contradiction in the fact that 2 is double of 1 and half of 4.Plato was often in trouble because he did not understand relative terms.He thinks that if A is greater than B and smaller than C, then A is both large and small at the same time, which in his view is a kind of contradiction.This trouble is a philosophical infantilism. The distinction between reality and appearance would not have the conclusions assigned to it by Parmenides and Plato and Hegel.If appearance really has representation, it is not nothing, and for that reason it is part of reality; this is a correct Parmenidean argument.Why should we bother with phenomena if they really have no expression?But someone may say: "Phenomenon really does not appear, but it appears to appear."This is of no use either, because we can still ask: "Does it really appear to appear? Or does it only appear to appear to appear?" Even if the phenomenon appears to appear, sooner or later we always have It will reach something real. There is something to express, so it is a part of reality.Plato would never have dreamed of denying that there are many beds represented before us, though there can be only one real bed, the one created by God.But he does not seem to face up to the implications of the fact that we have many manifestations before us, and this "many" is part of reality.Any attempt to divide the world into parts so that some parts are more "real" than others is doomed to failure. Connected with this is another curious insight of Plato's, that knowledge and opinion must concern different subjects.We should say: If I thought it was going to snow, that was opinion; if afterwards I saw that it was snowing, that was knowledge; but in both cases the subject matter is just the same.But Plato thought that as long as it can become an opinion at any time, it can never become the material of knowledge.Knowledge is infallible and infallible; opinion is not only infallible but necessarily infallible, since it assumes the reality of that which is mere appearance.All this repeats what Parmenides has already said. There is one aspect in which Plato's metaphysics clearly differs from that of Parmenides.For Parmenides, there is only one; but for Plato, there are many ideas.Not only beauty, truth, and goodness; but, as we have seen, God's creation of the heavenly bed, the heavenly man, the heavenly dog, the heavenly cat, etc., and everything that was in Noah's ark have.However, all this seems to have not been well thought out in "The Nation".Plato's Idea or Form is not thought, although it may be the object of thought.However, since the existence of ideas is timeless, when God decides to create, unless he already has in his mind the Platonic bed itself which is said to have been created by him as an object, he will not can decide to create a bed; so it is difficult for us to understand how God could create ideas.Anything without time must not have been created.Here we encounter the difficulty that has vexed many philosophically minded theologians.Only this accidental world, this world within time and space, can be created; but again it is the everyday world that has been dismissed as unreal and bad.So the Creator seems to have created nothing but illusion and evil.Certain thoroughgoing Gnostics simply adopted this view; but in Plato the difficulty has not come to the surface, and in the States he seems never to have been aware of it. To be a defender of the country, the philosopher must, according to Plato, go back to the cave and live among those who have never seen the light of truth.It seems that God Himself, if he wanted to transform His own creation, had to do so; a Christian Platonist could explain the incarnation of Christ in this way.But it is still quite impossible to explain why God should not be satisfied with the world of ideas.When the philosopher discovers the existence of caves, he is driven by kindness to return to them; but one would think that if the Creator had really created all things, he could have avoided caves at all. Perhaps this difficulty arises only from the Christian idea of ​​a Creator, and Plato cannot be blamed; Plato said that God did not create everything, but only good things.According to this point of view, the multiplicity of the sensory world should have other sources besides God.Perhaps ideas were not created by God. created, but only part of God's essence.Thus the pluralism evidently implied by the multiplicity of ideas is not fundamental.The most fundamental thing is God, or goodness, and the idea is to describe God.At any rate, this is one possible interpretation of Plato.Plato then proceeds with an interesting description of the specialized education necessary for a young man who would become a defender of the country.We have seen that the young man is selected for this honor according to a combination of intellectual and moral qualities: he must be upright, refined and studious, with a good memory and a harmonious mind.Young men selected for these merits were to study from twenty to thirty years the four Pythagorean sciences: mathematics (one-sided and three-dimensional), geometry, astronomy, and harmony .These studies must not be pursued in any utilitarian spirit, but merely to prepare his mind for insights into eternal things.For example, in astronomy, he should not pay too much attention to actual celestial bodies, but should be concerned with the mathematics of the motion of ideal celestial bodies.This may sound absurd to modern ears; yet, strange to say, it has proved to be a very useful point of view in experimental astronomy.The way in which this situation has arisen is very strange and deserves our deep thinking. The motions exhibited by the planets, until they have been deeply analyzed, have always appeared irregular and complex, and never of the kind chosen by a Pythagorean creator. look.Apparently, every Greek felt that the celestial bodies were supposed to embody mathematical beauty, and that the planets could only do so when they moved in circles.This will be especially evident to Plato because of his emphasis on the good.The question thus arises: is there any hypothesis capable of translating the apparent disorder of planetary motion into order, beauty, and simplicity?If anything, the idea of ​​the good would justify our assertion of this hypothesis.Aristotle of Samos found such a hypothesis: all the planets, including the earth, revolve around the sun in circles.This view has been rejected for two thousand years, partly on the authority of Aristotle, who attributed a rather similar hypothesis to the "Pythagorean school" ( 《论天》293a）。这种学说又被哥白尼所复活了，而它的成功似乎证明了柏拉图在天文学上的审美偏见是正当的。然而不幸开普勒发见了行星是以椭圆形而不是以圆形在运动着的，太阳位于一个焦点而不是位于圆心；后来牛顿又发现了它们甚至于不是以严格的椭圆形在运动着的。于是柏拉图所追求的，而且显然是被撒摩的亚里士达克所发现的，那种几何学的单纯性就终于证明是虚妄的了。 这一段科学史就说明了一条普遍的准则：任何假说不论是多么荒谬，都可.以.是有用的，假如它能使发现家以一种新的方式去思想事物的话；但是当它幸运地已经尽了这种责任之后，它就很容易成为继续前进的一种障碍了。把对于善的信仰当作科学地理解世界的一把钥匙，这在一定的阶段上对天文学曾经是有用的，但是在以后的每一个时期它都成为有害的了。柏拉图的——尤其是亚里士多德的——伦理的与审美的偏见曾大大地扼杀了希腊的科学。 值得注意的是，尽管柏拉图对于算学和几何学赋予了极大的重要性，而且算学和几何学对于他的哲学也有着极大的影响；但是近代的柏拉图主义者却几乎毫无例外地全都不懂数学。这就是专业化的罪过的一个例子：一个人要写柏拉图，就一定得把自己的青春都消磨在希腊文上面，以致于竟完全没有时间去弄柏拉图所认为是非常重要的东西了。