5 Classical Greek thought
Ancient Greek Philosophy
Classical philosophy emerged in ancient Greece, following a procession from what are known as the Presocratics; to the three great philosophers, Socrates (470–399 BCE), Plato (c. 428–347 BCE), and Aristotle (384–322 BCE); and then to later schools of thought, including the Epicureans and Stoics. As is the case with all ancient societies, knowledge of these thinkers is limited by the documentation that has survived. Socrates, for example, wrote down nothing. Rather, Plato wrote dialogues featuring his mentor Socrates engaged in philosophical debate with various individuals in Athens, some of them his fellow citizens and other prominent visitors to the city. Aristotle also wrote dialogues, like Plato, but none of those have survived: what we have are books that seem to have been based around lectures that he gave to students at the school he founded. Many other classical Greek philosophers survive only in fragments, sometimes quoted in letters or by later authors, brief snatches out of thousands of works that have been lost forever.
The material that has survived from ancient Greece has fueled philosophical discourse for two millennia. Indeed, this material survived when almost everything else from that time period is lost precisely because its authors were so admired. Generation after generation of later thinkers recopied, quoted and commented on these works up until the present day.
Plato and Aristotle, in particular, are often considered to be the originators of the Western intellectual tradition. While they themselves were influenced by earlier thinkers and were not seen as peerless visionaries by other Greeks at the time, the impact of their writings on later thought is extraordinary. If we trace the ideas, methods, assumptions, and questions addressed by later Western intellectuals back to their origins, we generally find Plato, Aristotle or both standing prominently right near the beginning. Insofar as Western civilisation is an shared intellectual lineage, Plato and Aristotle have the best claim to be its fathers. The twentieth century philosopher A.N. Whitehead claimed that the European philosophical tradition “consists of a series of footnotes to Plato”, and Aristotle was Plato’s first and most influential commentator. Aristotle also was the central, authoritative author on natural philosophy, his works forming the core of the ‘science’ curriculum until at least the 17th century and setting the stage for the European ‘Scientific Revolution’.
The Presocratics
The term Presocratics is a bit of a problem. At least a few of the thinkers considered part of this school were contemporaries of Socrates and are mentioned in Plato’s dialogues. It hardly seems to fair therefore to call them ‘Presocratic’, since they may have known the man and some outlived him. Foremost among these are the Sophists, traveling teachers of rhetoric who serve as foils for Plato’s philosophers. Plato sought to distinguish philosophers, seekers of truth, from Sophists, whom he regarded as seeking wealth and fame and peddling in fallacious arguments. Indeed, one of the most prominent Sophists, Protagoras, is a main character in the dialogue that bears his name.
Researching the Presocratics is difficult because so little of their work has survived. What we have is fragmentary and often based on the testimony of later philosophers, often Plato or Aristotle. Still, based on the work that is available, we can characterize the Presocratics as interested in questions of metaphysics and natural philosophy, with many of them proposing that nature consisted of one or more basic substances.
The fragments of the works of these early philosophers that have come down to us focus on metaphysical questions. One of the central debates among the Presocratics is between monism and pluralism. Those who think nature consisted of a single substance are called monists, in contrast to pluralists, who see it as consisting of multiple substances. For example, the monist Thales of Miletus thought that the basic element that comprised everything was water, while Empedocles the pluralist sought to show that there were four basic elements (earth, air, fire, and water) that were resolved and dissolved by the competing forces of love and strife.
Prominent Monists
Presocratic philosophers who sought to present a unified conception of nature held that nature ultimately consists of a single substance. This proposition can be interpreted in various ways. The claim proposed by Thales of Miletus (620–546 BCE) that the basic substance of the universe was water is somewhat ambiguous. It might mean that everything is ultimately made of water, or it might mean that water is the origin of all things. Thales and two of his students, Anaximander and Anaximenes, made up the monist Milesian school. Anaximander thought that water was too specific to be the basis for everything that exists. Instead, he thought the basic stuff of the universe was the apeiron, the indefinite or boundless. Anaximenes held that air was the basic substance of the universe.
Parmenides, one of the most influential Presocratic monists, went so far as to deny the reality of change. He presented his metaphysical ideas in a poem that portrays himself being taken on a chariot to visit a goddess who claims she will reveal the truths of the universe to him. The poem has two parts, “the Way of the Truth”, which explains that what exists is unified, complete, and unchanging, and “the Way of Opinion”, which argues that the perception of change in the physical world is mistaken. Our senses mislead us. Although Parmenides’s claim that change is not real might seem absurd to us, he and his student Zeno advanced strong arguments. Parmenides was the first person to propose that the light from the moon came from the sun and to explain the moon’s phases. In this way, he showed that although we see the moon as a crescent, a semicircle, or a complete circle, the moon itself does not change (Graham 2013). The perception that the moon is changing is an illusion.
Zeno proposed paradoxes, now known as Zeno’s paradoxes, that demonstrate that what we think of as plurality and motion are simply not possible. Say, for example, that you wish to walk from the library to the park. To get there, you first must walk halfway there. To finish your trip, you must walk half of the remaining distance (one quarter). To travel that final quarter of the distance, you must first walk half of that (an eighth of the total distance). This process can continue forever—creating an infinite number of discrete distances that you must travel. It is therefore impossible that you arrive at the park. A more common way to present this paradox today is as a mathematical asymptote or limit (such as this diagram depicts). From this point of view, you can never reach point a from point b because no matter where you are along the path, there will always be a distance between wherever you are and where you want to be. That is just one of several different paradoxes Zeno developed, including the paradox of the arrow and the parable of Achilles and the Tortoise.
Prominent Pluralists
Parmenides and Heraclitus (525–475 BCE) held diametrically opposed views concerning the nature of the universe. Where Parmenides saw unity, Heraclitus saw diversity. Heraclitus held that nothing remains the same and that all is in flux. One of his most well-known sayings illustrates this well: “[It is not possible to step twice into the same river]. . . . It scatters and again comes together, and approaches and recedes” (quoted in Curd 2011, 45).
Anaxagoras (500–428 BCE) and Empedocles (494–434 BCE) were substance pluralists who believed that the universe consisted of more than one basic kind of “stuff.” Anaxagoras believed that it is mind, or nous, that controls the universe by mixing and unmixing things into a variety of different combinations. Empedocles held that there were four basic substances (the four elements of air, earth, fire, and water) that were combined and recombined by the opposing forces of love and strife.
Finally, there are the schools of the atomists, who held the view that the basic substance of the universe was tiny, indivisible atoms. For the atomists, all was either atoms or void. Everything we experience is a result of atoms combining with one another. We will discuss atomism in Chapter 7, as those ideas were developed further in Hellenistic times.
Presocratic Theology
The Presocratic philosopher Pythagoras (570–490 BCE) and his followers, known as the Pythagoreans, comprised a rational yet mystical sect of learned men and women. Like Socrates, Pythagoras wrote nothing, so scholars continue to debate which ideas originated with Pythagoras and which were devised by his disciples. Among the Pythagoreans’ key beliefs was the idea that the orderly nature of universe was based on numerical ratios that structure it. For example, the Pythagoreans had learned that musical intervals were based on mathematical ratios, such as those created by vibrating strings of different lengths. A vibrating string of half the length of another creates a musical note one octave higher, which sounds to our ears like somehow the ‘same’ note. Other intervals are created from lengths of 2/3 and 3/4, and the entire musical system of scales used in ‘classical’ music traces back to these Pythagorean ratios. A reminder of their mathematical legacy can be found in the Pythagorean theorem, which students continue to learn in school. Pythagoreans also believed in the transmigration of souls, an idea that Plato would adopt. According to this doctrine, the soul outlives the body, and individuals are reborn after death in another human body or even in the body of a nonhuman animal.
Another important Presocratic philosopher who produced novel theological ideas is Xenophanes (c. 570–478 BCE). Xenophanes, who was fascinated by religion, rejected the traditional accounts of the Olympian gods. He sought a rational basis of religion and was among the first to claim that the gods are actually projections of the human mind. He argued that the Greeks anthropomorphized divinity, and like many later theologians, he held that there is a God whose nature we cannot grasp. Using rational arguments to try to understand the nature of the divine rather than relying purely on myths, priests, or written authority became important both for Plato and for many, many subsequent Western philosophers.
Plato
Socrates and the love of wisdom
The Socrates that we know today is mostly a creation of Plato. The man wrote nothing himself, and the view we get of him in other contemporaries such as Aristophanes and Xenophon is a pale shadow of the vivid, funny, fiercely intelligent, sincere and courageous philosopher we find in Plato’s writings. The character of Socrates in the dialogues is no doubt an idealized version of the man as he lived, but the more significant question is how we distinguish the philosophical views of Socrates from his disciple who wrote in his voice. Suffice to say that the question is complex, but we have at least some idea of which ideas are Socrates and which are original to Plato.
The Socrates we meet in the early Platonic dialogues is a memorable and unusual person. He claims not to know very much, and asks people to explain various concepts to him, such as piety or virtue. But the shrewd questions he asks soon undermine the explanations he is given by whoever he is talking with. They begin to realize that it is harder than they thought to explain these ideas which seemed, on the surface, clear and obvious. The more we read Socrates words, the more we realize he is always three steps ahead of his companions, politely encouraging them to try again before he easily refutes their latest idea. One starts to wonder if we know anything at all that Socrates could not call into question, making our definitions and explanations seem a little silly as he shows why they cannot be right.
This questioning attitude towards accepted knowledge and commonly held views was the centre of Socrates’ appeal both in his own time and today. That we should seek after the truth by asking questions, even if everyone already thinks we know the answers, is both a powerful and a dangerous idea. It is dangerous because it threatens accepted governments, religion, morality, and even society itself, all of which are based on shared agreement about important beliefs. But it is powerful because it allows us to understand the world better, and perhaps to improve the societies in which we live. Plato would also say that we naturally love the truth, that we cannot help preferring truth to falsehood any more than we can help preferring beauty to ugliness or pleasure to pain. So we are driven by our nature to love and seek truth, no matter how much society might prefer we didn’t. Perhaps the most important idea that Plato and Socrates shared is that the pursuit of truth and wisdom is good in itself, and that the pursuit is essential. We do not have all the answers, and the beginning of wisdom is to accept that we are ignorant of many things — we are even ignorant of the extent of our ignorance. But we have to keep looking for truth. The unexamined life is not worth living.
This willingness to question accepted beliefs is also the basis of one of the most basic kinds of human freedom: freedom of thought. Every society demands a great deal of conformity of behaviour from its members, and for most of us most of the time, the social rules we live by are almost invisible because we accept them without question. But demanding conformity of belief is quite different from conformity of behaviour, and in every society there are some people, often many, who reject commonly held views. Socrates is one of the most famous historical examples of a nonconformist thinker who defied the pressure of society to accept what everyone else does, and died for it. As Plato tells it, Socrates was more than merely a nonconformist: he was a man tried to live righteously and would rather die than do wrong, an ethical thinker who lived his own ethics.
In 399 BCE, Socrates was accused of impiety and corrupting the youth, put on trial, sentenced to death, and executed. Our main source for this is Plato’s philosophical dialogues, but other contemporary authors such as Xenophon confirm the outlines of the story. In Plato’s dialogues, Socrates is accused because of the enmity aroused by his questioning, alienating powerful men and raising fears that he might be causing the youth to doubt morality and the existence of the gods. At his trial, Socrates argues that, on the contrary, Athens owes him a debt of gratitude for acting as a gadfly, afflicting the comfortable and startling people out of their ignorance. His only wisdom is that he knows he doesn’t know the answer to important questions like ‘what is justice’. When he shows people that are equally ignorant, he is doing them a service. It is better to know you are ignorant than mistakenly think you have all the answers.
The prospect of being executed does not frighten Socrates, since he doesn’t know whether death is a good or bad thing. One of the few things he is sure of is that it is better to do right than wrong, which makes him an unlikely candidate to corrupt the youth. In Plato’s dialogue Crito, set after he is convicted and sentenced to death, Socrates refuses the opportunity to escape from prison before his execution. He tells Crito, who wants to rescue him, that he will agree to escape only if Crito can persuade him it is the right thing to do. Socrates argues that even if his conviction was unjust he still has a moral obligation to obey Athens’ laws, and Crito fails to make a convincing counterargument. Socrates therefore accepts his death penalty, spending his last hours discussing whether the soul is immortal and there might be life after death.
Socrates, in both life and death, seems to have made a powerful impression on the people around him, not least the young wrestler Aristocles, who went on to immortalize him as the main character in his brilliant writings. ‘Plato’ was Aristocles nickname, a word meaning ‘broad’, perhaps referring to his wrestling physique. Like many of the young men who hung around Socrates, Plato came from a wealthy background and viewed Athenian democracy with a skeptical eye. But his main commitment seems to have been living and thinking in emulation of his teacher Socrates: fearlessly questioning beliefs to search after the truth. To do this, he developed a writing style that modelled itself after the free-flowing discussions that Socrates had held in Athens’ streets and dining rooms: the philosophical dialogue. These writings present characters speaking to one another and responding to each other’s questions. Socrates is often but not always the main character, and usually he comes across best in the discussion, but often there is no final decision about what view is correct. Instead, the dialogues model a process for seeking after the truth: dialectic, a reasoned discourse where the participants may have differing opinions but share the goal of finding the answer to an important question. The participants use logical arguments, propose definitions, and critique each other’s suggestions in order to weed out false ideas. Plato’s dialogues therefore do not merely set out some philosophical ideas and argue for them: they offer a vivid model of how to do philosophy and how to live as a philosopher. Living as a philosopher does not mean working in a university or teaching students: for Plato and the culture he inspired, anyone can be a philosopher. You just have to accept that you might be wrong in many of your opinions and spend some time and effort seeking the truth with like-minded people.
Plato’s Forms
In Plato’s later dialogues the character Socrates moves away from the actual person and becomes the speaker for Plato’s developing views. These include what comes to be known as the theory of the forms, a metaphysical doctrine that holds that every particular thing that exists participates in an immaterial form or essence that gives this thing its identity. So what beautiful things have in common is that they participate in the immaterial form of beauty, which is realized in diverse ways in concrete visible objects. Similarity between objects indicates that they each instantiate the same form, and the identity of the form explains the similarity of the objects.
The invisible realm of the forms differs fundamentally from the changing realm we experience in this world. The invisible realm is eternal, unchanging, and perfect. The material things themselves change, but the immaterial forms remain the same. Consider, for example, the form of a rectangle: four adjacent straight sides that meet at 90-degree angles. You can draw a rectangle, but it is an imperfect representation. The desk or table you are sitting at might be rectangular, but are its edges perfectly straight? How perfect was the instrument that cut the sides? If you nick the edge of a table, then it changes and becomes less like the form of a rectangle. With the doctrine of forms, Plato may be said to combine the metaphysics of Parmenides with that of Heraclitus into a metaphysical dualism, offering a solution to the problem of how both change and knowledge are possible.
When we observe the world, we see appearances, and make judgments about the objects that are behind the appearances. But for Plato, this is not real knowledge: it is like a shadow play, where the puppets casting the shadows, the objects of the ‘real’ world, are just copies of the really real world, the eternal world of forms. Plato develops this idea in a very famous story, the ‘myth of the cave’, where he compares our life to prisoners, chained so they can only stare at the wall where the shadows move about. Most people are content looking at the shadows, and that is the only world they know, although they infer the existence of the puppets casting the shadows. They cannot look behind and see the puppets, let alone the real things that the puppets are made in imitation of. Real knowledge is of the forms, because they are permanent and unchangeable, and unify and explain the nature of the physical world. Physical knowledge and knowledge based on our senses is, for Plato, mere belief and opinion, not real knowledge. Only some philosophers manage to free themselves from the chains and go up out of the cave to the real world. There the light of the sun (which Plato says is the form of Good in the allegory) dazzles their eyes and it is hard for them to see the real objects (the forms), but still, by doing so they gain some real knowledge. Unsurprisingly when a philosopher tries to tell other people about this, they are skeptical and prefer to believe in their shadows.
Plato on ethics and politics
The most important form is the form of Good. Plato argues that humans naturally love the good and are drawn to it — after all, who wants something that they think is bad? So anything we desire, we think is good. Therefore if we want bad things or do bad things it must be out of ignorance, because we mistakenly think something is good which is really bad. Human nature is good, and evil comes from ignorance — which is why philosophy is so important!
Since evil comes from ignorance, rulers should be philosophers — that is, they should be people who seek after wisdom and are the least ignorant about what is really good. Why would we expect someone to be a good ruler who doesn’t know what goodness, fairness or justice is? Yet philosopher-kings never have perfect knowledge because our understanding is based on a material realm that is always changing. True knowledge is only possible of the forms themselves, and even then philosophers are seekers of such knowledge, not necessarily in firm possession of it.
In Plato’s telling, the people who are least happy of all are tyrants and other wicked people who oppress others. We might foolishly envy their ability to fulfil their every whim and destroy their enemies. But really, such people are harming themselves worse than any of their victims: they harm their own souls by mistaking their immediate pleasure for the highest good and allowing their passions to rule over their reason. Tyrants live in fear of their many enemies, have no real friends, and soon learn the hollowness of a life built on luxury and fulfilling one’s passing whims. They are pitiable. The best life is the life lived in pursuit of the good and the true.
This is a theme that Plato returns to many times in his writings, having Socrates debate people who argue that humans are selfish, that fulfilling your desires is the only thing that matters, or that there is nothing to justice other than the strongest setting the rules. In the Greece of Plato’s day, many cities were ruled by tyrants who had seized power, and the expansion of Athens’ maritime empire had opened opportunities for unscrupulous men to make a profit at others’ expense. The moral relativists or nihilists Socrates confronts in Plato’s dialogues advocate views that were as relevant and troubling in his own time as they remain today. Is there any reason to be ethical at all? Are moral rules invented by societies, or by powerful people such as kings? How should we live if we want to be happy? Plato responds to all these questions by asserting that the Good is real, is objective, had always existed and will always exist, and is unchangeable. If we want to be happy, we have to seek the good, and only by living an objectively good life can we have a subjectively good life.
In the case of both individuals and states, for this to happen we have to be guided by our intellect, which must rule over our desires and emotions. Only our intellect can apprehend the Good. Only our intellect can control our tendency to sabotage ourselves by preferring short-sighted and selfish pleasure-seeking over the actions that benefit both us and society in the long run. If our intellect drives the chariot and keeps the horses of desire and emotion reined in, our soul or our state is well ordered and good.
This view has its appeal, but politically expressed quite elitist ideas. Plato associated the poor and uneducated population with the desires of the soul, and thought that a properly ordered city needed to be divided into distinct social classes with distinct roles. The ordinary people should not have any say in government, since they were not really good at philosophical investigation. The ruling class for Plato were not hereditary and should not be the wealthy: the vision was of a meritocracy, where tests could separate out the philosophically promising from the rest of the population and give them special education. This educated elite could be given the ruling power that, as philosophers, they would not really want but could be trusted with. Plato presents this state more as an imaginary vision than a concrete plan, but the idea that a just and philosophical ruler could be a philosopher king and form the ideal type of government would become part of the ideology of kingship in the Western world.
Aristotle
During the Middle Ages, people referred to Plato’s most famous pupil Aristotle as simply “the Philosopher.” This nickname is a testament to his enduring fame, as well as to the fact that he was driven by philosophical curiosity to try to understand everything under the sun. The first sentence of his famous work Metaphysics states, “Philosophy begins in wonder.” He exemplified this claim in his writing. His works ranged widely across all the main areas of philosophy, including logic, metaphysics, and ethics. In addition, he investigated natural philosophy, the fields of study that eventually gave rise to science. Aristotle also researched topics that would today be classified as biology and physics. Stylistically, his work was very different from that of his teacher. While Plato’s work was literary and even dramatic, Aristotle’s surviving writings are presented as lectures and may even have been his lecture notes for classes he taught. We are told that he wrote polished philosophical dialogues like Plato, but they have not survived.
One reason for Aristotle’s lasting influence is that he offered an extremely complete and self-consistent set of views, which are both supported by argument and, in many cases, intuitively appealing. A student of Aristotle learns answers to many questions, and also learns methods to address almost any other question that may arise. Many later authors are recognizably ‘Aristotelian’, in that even where they disagree with or elaborate on Aristotle’s views, they accept his central concepts, use his logic, and explain things in the same ways he did.
Explanations
At the centre of Aristotle’s work was his doctrine of the four causes. He believed that the nature of any single thing could be understood by answering four basic questions: “What’s it made of?” (material cause), “What shape does it have?” (formal cause), “What agent gave it this form?” (efficient cause), and, finally, “What is its end goal?” (final cause). Answering these questions gives us natural knowledge about the world we live in. Aristotle rejects Plato’s forms, believing that concepts have only a psychological reality and that they correspond to properties that exist in objects and not in any non-physical sense.
Aristotle’s Ethics
For any living thing, its good is relative to its nature and defined by what it is — what is good for a pig is not good for a fish, after all. And for every living thing, its natural goals (its final causes) are good for it to pursue, and by achieving those goals it lives the best life that a thing of that kind can live. An indication that something is living its best life is that it has fully realized its potential. This is true for humans as much as for any living thing, and so we should expect that the best life for humans, that which is good for them, happens when humans successfully pursue their natural goals and fully realize their potential.
Aristotle says that happiness is the final goal of human life, since it is the one thing that we pursue for its own sake, and not for the sake of something else. A happy life is one where we are living as well as possible, and to do this we must both develop and use our reason. We are often faced with difficult choices and urged by our emotions into poor decisions, and only by properly using our reason can we find the right course and pursue our goals well. This a distinctive capacity of humans, and making these practical moral judgments well is necessary to live a good human life. Aristotle calls this goal of reason the “golden mean”, where we find the correct balance between two extremes of thoughtless action.
For example, we are often afraid of dangerous situations. Disregarding this fear entirely is foolhardy, even suicidal, but if we are ruled entirely by our fear we will make cowardly choices that often turn out to be mistakes. In Aristotle’s own time male citizens were expected to serve as soldiers and fight when needed, and cowardly refusal would lead to mockery, hatred, and punishment. But even in everyday modern life, fear of flying, or needles, or unpleasant confrontations, can lead us into unwise choices that ultimately make us unhappy. Finding the golden mean through the use of reason results in a life of virtue, where we cultivate our ability to control our desires and emotions and take those actions which we know to be correct. The life of virtue is not sufficient to be happy, since a virtuous person stricken by suffering or misfortune beyond their control is hardly happy, but virtue is necessary for happiness. By using their reason properly to achieve their goals and finding the golden mean, virtuous people fulfill their human, rational natures and live as well as humans can.
Politics
Part of human nature for Aristotle is our sociability, and he argued that we can only live virtuously and happily in a social, political context. Groups of people form communities, and these communities have goals like everything else in Aristotle’s thought. The goal of a community is the common good of its members. A state is the largest kind of community, to which all the smaller communities that make it up are subordinated. Insofar as a state is well constituted, that is, had good laws and customs, it will serve the interests of its members and allow them to flourish. Many states, of course, fall short of this goal, diverging from this proper purpose. Aristotle examines the specific constitutions of laws of a variety of different states, and also develops a general scheme for categorizing states into types.
| Constitution promotes common good | Constitution promotes good of rulers | |
| Single Ruler | Monarchy | Tyranny |
| Few Rulers | Aristocracy | Oligarchy |
| Many Rulers | Polity | Democracy |
The types of state are defined by the size of the ruling body of the state, and by whether the state is organized in such a way as to promote the common good of the citizens or to promote the more narrow good of the ruler(s). Surprisingly to modern readers, Aristotle is not much more sympathetic to democracy than Plato was, although he thinks it is the least bad of the bad types of government. That is because in a democracy, the poor majority use their voting power to serve their own interests, which while not ideal at least helps most of the people in the state. Tyranny is the worst sort of government, since not only is it serving the selfish desires of a single person, the ruler has to resort to vicious acts to maintain power.
The Cosmos
This chapter contains material from
Introduction to Philosophy: Chapter 4 by Nathan Smith et. al, OpenStax and is used under a CC BY 4.0 license.
Media Attributions
5.1 Presocratics Had Different Views About the Arche by Rice University, OpenStax is licensed under CC BY 4.0
5.2 Plato’s Allegory of the Cave by 4edges is licensed under CC BY-SA 4.0
5.3 Three Main Types of Living Souls for Aristotle by Rice University, OpenStax is licensed under CC BY 4.0
5.4 The Aristotelian Cosmos by Fastfission, in the public domain
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- An_Illustration_of_The_Allegory_of_the_Cave,_from_Plato’s_Republic © 4edges is licensed under a CC BY-SA (Attribution ShareAlike) license
- Ptolemaicsystem-small © Fastfission
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