Exploring Immortality
Plato's Phaedo

Table of Contents

Picture of <b>Athanasia Giasoumi</b><br><small>PhD in Philosophy, University of Patras</small>
Athanasia Giasoumi
PhD in Philosophy, University of Patras

Warm-Up: So, What Happens After Death?

We all wonder what happens when we die. Do we simply cease to exist when our bodies perish, or does our existence continue through our souls’ survival in a realm beyond the physical? If there is indeed an afterlife, how can we determine whether we will find happiness or sorrow there? Different religions offer diverse perspectives on this profound topic, but today we delve into philosophical reflections on these questions. We will focus on Plato’s insights, presented in his dialogue Phaedo.

Introduction

Plato (428/427–348/347 BC), a towering figure in ancient Greek philosophy, laid the foundations of Western thought and continues to influence contemporary debates. Born in Athens, Plato was a disciple of Socrates, the central character in most of his dialogues. In 387 BCE, Plato founded the Academy, a prestigious center of learning that attracted diverse scholars and thinkers, including Aristotle, a philosopher who would also become highly influential. Plato’s works, written in the form of dialogues, explore fundamental questions about ethics, politics, epistemology, aesthetics, and metaphysics. Plato’s profound impact on Western thought is exemplified by what the British philosopher A.N. Whitehead said about him: “The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato.”

In Plato’s dialogue, the Phaedo, we are privy to the final hours of Socrates before his death by hemlock. Narrated by Phaedo, a close friend and devoted disciple of Socrates, the dialogue recounts the philosophical discussions that unfolded, delving into profound metaphysical and ethical questions about the nature of the soul, life, and death. The central theme of these discussions—and the focus of our exploration here—is the concept of the soul’s immortality. We will concentrate on key passages from the dialogue that showcase Socrates’ engagement with his friends and followers, most notably Simmias and Cebes, as they grapple with the profound implications of mortality and the potential for an afterlife. For those intrigued, the complete Phaedo can be accessed here.

Key Concepts

Death – Plato understands this as the soul’s separation from the body.

Immortality of the Soul – Unlike the body, the soul is not subject to physical death, because it is immortal and indestructible.

Recollection – The soul existed prior to birth; during this time it learned everything, and hence all learning is only recalling what we already know.

Philosophy – The practice of preparing the soul for death by training it to think and exist independently of the body.

Forms – The perfect, divine, and intelligible entities that exist independently of the physical world. They are comprehensible only through reason, not through our senses, and their existence explains the properties of objects in the physical world. For example, consider the concept of beauty. We recognize beauty in various objects and experiences – a sunset, a painting, a person – but what is beauty itself? Plato would argue that there exists a Form of Beauty, an eternal and unchanging essence that all beautiful things participate in. Similarly, the concept of justice is not tied to any particular law or action but exists as a Form of Justice, an ideal standard against which we can measure the justness of our laws and actions.

The Circle of Life?

In 4th-century-BCE Athens, opinions on the soul varied: some believed in its mortality, others in its immortality. Consequently, Socrates’ pupils were perplexed about what transpired after death. However, Plato’s Socrates, facing death, is convinced of the soul’s immortality and is confident that after he dies his soul will join the gods because of his virtuous life, dedicated to philosophy. He maintains that people should only fear death if they have lived immorally. To prove the immortality of the soul, he presents four arguments, which posit that the soul not only predates birth but also endures beyond an individual’s demise, due to its eternal nature and indestructibility. We’ll call the first argument The Argument from Opposites.

70c–72e

“Now,” said he, “if you wish to find this out easily, do not consider the question with regard to men only, but with regard to all animals and plants, and, in short, to all things which may be said to have birth. Let us see with regard to all these, whether it is true that they are all born or generated only from their opposites, in case they have opposites, as for instance, the noble is the opposite of the disgraceful, the just of the unjust, and there are countless other similar pairs. Let us consider the question whether it is inevitable that everything which has an opposite be generated from its opposite and from it only. For instance, when anything becomes greater it must inevitably have been smaller and then have become greater.”

[…]

“Now,” said Socrates, “I will tell about one of the two pairs of which I just spoke to you and its intermediate processes; and do you tell me about the other. I say one term is sleeping and the other is being awake, and being awake is generated from sleeping, and sleeping from being awake, and the processes of generation are, in the latter case, falling asleep, and in the former, waking up. Do you agree, or not?”

“Certainly.”

“Now do you,” said he, “tell me in this way about life and death. Do you not say that living is the opposite of being dead?”

“I do.”

“And that they are generated one from the other?”

“Yes.”

“Now what is it which is generated from the living?”

“The dead,” said he.

“And what,” said Socrates, “from the dead?”

“I can say only one thing—the living.”

“From the dead, then, Cebes, the living, both things and persons, are generated?”

This passage discusses the concept of opposites and the process of generation. Socrates claims that everything with an opposite is generated from that opposite. He uses examples to illustrate this concept: sleeping versus being awake and living versus being dead. Just as wakefulness arises from sleep and vice versa, Socrates contends that the living emerge from the dead, and the dead from the living. This cyclical interplay suggests that the souls of the deceased must exist in some realm before being reborn into the world of the living. This implies the pre-existence of the soul, supporting the idea of its immortality.

Do It Yourself!

The Opposites Game

Life is a stage for a ceaseless interplay of opposites. But how often do we observe this in our own lives? For one day, become a detective of duality. Identify at least three pairs of opposites you encounter. Does the idea that opposites create each other always hold true? Can you think of any exceptions? Bonus points if you can explain why!

We Can Only Learn What We Already Know

In further support of his claim that the soul is immortal, Socrates presents the Argument from Recollection.

72e–77a

[…] Cebes rejoined, “if it is true, Socrates, as you are fond of saying, that our learning is nothing else than recollection, then this would be an additional argument that we must necessarily have learned in some previous time what we now remember. But this is impossible if our soul did not exist somewhere before being born in this human form; and so by this argument also it appears that the soul is immortal.”

[…]

“Now if we had acquired that knowledge before we were born, and were born with it, we knew before we were born and at the moment of birth not only the equal and the greater and the less, but all such abstractions? For our present argument is no more concerned with the equal than with absolute beauty and the absolute good and the just and the holy, and, in short, with all those things which we stamp with the seal of absolute in our dialectic process of questions and answers; so that we must necessarily have acquired knowledge of all these before our birth.”

“That is true.”

“But, I suppose, if we acquired knowledge before we were born and lost it at birth, but afterwards by the use of our senses regained the knowledge which we had previously possessed, would not the process which we call learning really be recovering knowledge which is our own? And should we be right in calling this recollection?”

“Assuredly.” […]

Argument

The Argument From Recollection

Plato’s Theory of Recollection was first introduced in his dialogue Meno in the form of a myth. In the Phaedo, Socrates presents the Theory of Recollection as an argument for the immortality of the soul. The theory suggests that learning is actually the recollection of knowledge that the soul acquired before birth. Socrates argues that our ability to understand abstract concepts or the Forms, such as equality and beauty, implies that we must have known about these entities before birth, as we cannot gain such knowledge from our experiences of the physical world. Therefore, the theory leads to the conclusion that the soul existed before birth and is immortal, as it must have acquired this knowledge in its previous existence.

Premise 1: All that we recollect was acquired during a previous period.

Premise 2: We perceive something with our senses (e.g., equal sensible objects) and conceive something different with our reason (e.g., the Equal itself, the Form of Equal).

Premise 3: We first know the abstract concepts (such as the Form of Equal) and then perceive the sensible objects that share the same name (like two equal pieces of wood).

Premise 4: We have senses and bodies at birth, and we perceive sensible objects after our birth.

Conclusion 1: Therefore, knowledge of the Forms precedes our birth.

Premise 5: If we knew the Forms before our birth, then we would have acquired this knowledge through our souls and not our bodies.

Conclusion 2: So, our souls precede our birth.

However, the pre-existence of the soul is insufficient to prove its immortality; it must also be argued that the soul persists after the body’s death. Socrates intends to establish this with the next two arguments he presents.

Okay, But What Happens After The Body’s Demise?

Despite their acceptance of the soul’s pre-existence, Simmias and Cebes still question whether the soul survives the death of the body. In response to their challenge, Socrates combines the preceding two arguments.

77c–77d

“It has been shown, Simmias and Cebes, already,” said Socrates, “if you will combine this conclusion with the one we reached before, that every living being is born from the dead. For if the soul exists before birth, and, when it comes into life and is born, cannot be born from anything else than death and a state of death, must it not also exist after dying, since it must be born again? So the proof you call for has already been given.”

Main Idea

The Souls Immortal Nature

Socrates interweaves the Argument from Opposites and the Recollection Argument to illuminate the enduring essence of the soul. The cyclical nature of opposites, as exemplified by the transition between life and death, hints at the soul’s continuous existence. The Recollection Argument, which posits that the soul possesses innate knowledge of the Forms, further supports this idea by implying the soul’s pre-existence. By synthesizing these arguments, Socrates constructs a compelling philosophical case for the soul as an eternal entity, transcending the physical world and intimately connected to the divine. The concept of the soul’s immortality, thus established, serves as a foundation for Socrates’ subsequent exploration in the Argument from Affinity.

The Dualism in Us

Socrates proceeds by employing the Argument from Affinity to elucidate the soul’s immortal and divine essence, in contrast to the body’s mortal and material attributes.

78b–80e

[…] “Now is not that which is compounded and composite naturally liable to be decomposed, in the same way in which it was compounded? And if anything is uncompounded is not that, if anything, naturally unlikely to be decomposed? […]

“Then it is most probable that things which are always the same and unchanging are the uncompounded things and the things that are changing and never the same are the composite things?”

“Yes, I think so.”

“Let us then,” said he, “turn to what we were discussing before. Is the absolute essence, which we in our dialectic process of question and answer call true being, always the same or is it liable to change? Absolute equality, absolute beauty, any absolute existence, true being—do they ever admit of any change whatsoever? Or does each absolute essence, since it is uniform and exists by itself, remain the same and never in any way admit of any change?”

“It must,” said Cebes, “necessarily remain the same, Socrates.”

“But how about the many things, for example, men, or horses, or cloaks, or any other such things, which bear the same names as the absolute essences and are called beautiful or equal or the like? Are they always the same? Or are they, in direct opposition to the essences, constantly changing in themselves, unlike each other, and, so to speak, never the same?”

“The latter,” said Cebes; “they are never the same.”

[…]

“And you can see these and touch them and perceive them by the other senses, whereas the things which are always the same can be grasped only by the reason, and are invisible and not to be seen?”

“Certainly,” said he, “that is true.”

“Now,” said he, “shall we assume two kinds of existences, one visible, the other invisible?”

“Let us assume them,” said Cebes.

“And that the invisible is always the same and the visible constantly changing?”

“Let us assume that also,” said he. 

“Well then,” said Socrates, “are we not made up of two parts, body and soul?”

“Yes,” he replied.

“Now to which class should we say the body is more similar and more closely akin?”

“To the visible,” said he; “that is clear to everyone.”

“And the soul? Is it visible or invisible?”

“Invisible, to man, at least, Socrates.”

[…]

“And the body?”

“Is more like the other.”

[…]

“Then see, Cebes, if this is not the conclusion from all that we have said, that the soul is most like the divine and immortal and intellectual and uniform and indissoluble and ever unchanging, and the body, on the contrary, most like the human and mortal and multiform and unintellectual and dissoluble and ever changing.”

The Argument from Affinity establishes a fundamental distinction between two realms: the visible, transient world of physical bodies and the invisible, eternal realm of the soul. The soul, being invisible and unchanging, shares a greater affinity with the divine and immortal Forms than with the perishable body. This suggests that while our bodies are subject to decay and dissolution, the soul, mirroring the eternal nature of the Forms, persists as an indestructible entity.

Connection

Dualism and Virtue

The Affinity Argument introduces a fundamental dualism between the immortal, unchanging soul and the mortal, changing body. This argument serves as a cornerstone of Plato’s philosophy, intricately linked to his theories of knowledge and ethics. The Affinity Argument establishes the soul’s unique capacity to grasp eternal truths, known as the Forms, through reason and philosophical inquiry. For Plato, this pursuit of knowledge transcends mere intellectual curiosity; it represents a moral imperative that guides the soul toward virtue. In contrast, the body, bound to the material world and its fleeting pleasures, can obstruct this pursuit. Thus, philosophical life is framed as a process of liberating the soul from the constraints of the body, enabling it to ascend to the realm of the Forms. 

Furthermore, the dualism presented in the Affinity Argument has influenced Western philosophy for centuries. This influence extends to the mind-body dualism articulated later by René Descartes, the 17th-century founder of modern philosophy.

Dissonance in Harmony

Once the Argument From Affinity has been presented, Simmias challenges Socrates by introducing a famous analogy that compares the soul–body relation to the harmony and strings of a lyre.

85c–86d

“[…] For, Socrates, when I examine what has been said, either alone or with Cebes, it does not seem quite satisfactory.”

[…]

“In this,” said he, “that one might use the same argument about harmony and a lyre with its strings. Once might say that the harmony is invisible and incorporeal, and very beautiful and divine in the well attuned lyre, but the lyre itself and its strings are bodies, and corporeal and composite and earthy and akin to that which is mortal. Now if someone shatters the lyre or cuts and breaks the strings, what if he should maintain by the same argument you employed, that the harmony could not have perished and must still exist? For there would be no possibility that the lyre and its strings, which are of mortal nature, still exist after the strings are broken, and the harmony, which is related and akin to the divine and the immortal, perish before that which is mortal. He would say that the harmony must still exist somewhere, and that the wood and the strings must rot away before anything could happen to it. And I fancy, Socrates, that it must have occurred to your own mind that we believe the soul to be something after this fashion; that our body is strung and held together by heat, cold, moisture, dryness, and the like, and the soul is a mixture and a harmony of these same elements, when they are well and properly mixed. Now if the soul is a harmony, it is clear that when the body is too much relaxed or is too tightly strung by diseases or other ills, the soul must of necessity perish, no matter how divine it is, like other harmonies in sounds and in all the works of artists, and the remains of each body will endure a long time until they are burnt or decayed. Now what shall we say to this argument, if anyone claims that the soul, being a mixture of the elements of the body, is the first to perish in what is called death?”

Objection

Simmias’ Objection: The Theory of Harmony

Simmias comes up with an intriguing analogy. He compares the soul-body relationship to the harmony produced by a well-tuned lyre. The harmony is beautiful and seemingly intangible, while the lyre and its strings are physical and subject to decay. Simmias argues that if the soul is like the harmony of a lyre, it cannot exist without the body, just as the harmony vanishes when the lyre is destroyed. This challenges the notion of the soul’s independent existence and immortality, suggesting that it might be inextricably linked to the physical body and perish along with it.

Socrates responds to Simmias’ objection (92a–94e) by presenting several key points to differentiate the soul from the attunement of an instrument. Firstly, Socrates argues that the soul—as they have already agreed following the previous arguments—exists before the body is formed, unlike the attunement of an instrument. Secondly, he highlights that there are degrees of attunement but no degrees of the soul. Thirdly, Socrates points out that if the analogy with attunement were correct, it would imply that no soul was better or worse than any other soul. This contradicts our understanding that an immoral soul is out of tune and in disharmony, whereas a virtuous soul is in tune and in harmony. Lastly, Socrates emphasizes that the soul is the master of the body, and this is unlike the relationship between an instrument and its attunement. These distinctions aim to illustrate the soul’s unique nature and refute Simmias’ analogy between the soul and the attunement of an instrument.

Challenge to Challenge!

Cebes raises a counterpoint to Simmias’ objection, which in turn challenges Socrates.

86e–88b

“I do not agree with Simmias’ objection, that the soul is not stronger and more lasting than the body, for I think it is far superior in all such respects. […] It seems to me that it is much as if one should say about an old weaver who had died, that the man had not perished but was safe and sound somewhere, and should offer as a proof of this the fact that the cloak which the man had woven and used to wear was still whole and had not perished. Then if anyone did not believe him, he would ask which lasts longer, a man or a cloak that is in use and wear, and when the answer was given that a man lasts much longer, he would think it had been proved beyond a doubt that the man was safe, because that which was less lasting had not perished.

“But I do not think he is right, Simmias, and I ask you especially to notice what I say. Anyone can understand that a man who says this is talking nonsense. For the weaver in question wove and wore out many such cloaks and lasted longer than they, though they were many, but perished, I suppose, before the last one. Yet a man is not feebler or weaker than a cloak on that account at all. And I think the same figure would apply to the soul and the body and it would be quite appropriate to say in like manner about them, that the soul lasts a long time, but the body lasts a shorter time and is weaker. And, one might go on to say that each soul wears out many bodies, especially if the man lives many years. For if the body is constantly changing and being destroyed while the man still lives, and the soul is always weaving anew that which wears out, then when the soul perishes it must necessarily have on its last garment, and this only will survive it, and when the soul has perished, then the body will at once show its natural weakness and will quickly disappear in decay. And so we are not yet justified in feeling sure, on the strength of this argument, that our souls will still exist somewhere after we are dead. For if one were to grant even more to a man who uses your argument, Socrates, and allow not only that our souls existed before we were born, but also that there is nothing to prevent some of them from continuing to exist and from being born and dying again many times after we are dead, because the soul is naturally so strong that it can endure repeated births,—even allowing this, one might not grant that it does not suffer by its many births and does not finally perish altogether in one of its deaths.” 

Objection

Cebes’ Objection: The Weaver-and-Cloak Analogy

Cebes disagrees with Simmias’ analogy and proposes his own. He compares the soul to a weaver and the body to the cloaks the weaver creates. Just as a weaver outlives many cloaks, the soul might outlive many bodies. However, Cebes points out that this doesn’t necessarily mean the soul is immortal. The weaver eventually dies, and so might the soul, even if it endures longer than any single body. This analogy adds a new dimension to the debate, highlighting the possibility that the soul, while resilient, might not be eternally indestructible.

The Final Argument: Sealing The Case For Immortality

While Simmias’ objection was simple to discuss and answer, Socrates is well aware that Cebes’ is significantly more challenging. This prompts him to make a final argument that renegotiates the relationship between the opposites. 

105b–107d: 

“[…] now that I see another safe reply deduced from what has just been said. If you ask me what causes anything in which it is to be hot, I will not give you that safe but stupid answer and say that it is heat, but I can now give a more refined answer, that it is fire; and if you ask, what causes the body in which it is to be ill, I shall not say illness, but fever; and if you ask what causes a number in which it is to be odd, I shall not say oddness, but the number one, and so forth. Do you understand sufficiently what I mean?”

“Quite sufficiently,” he replied. 

“Now answer,” said he. “What causes the body in which it is to be alive?”

“The soul,” he replied. “Is this always the case?”

“Yes,” said he, “of course.”

“Then if the soul takes possession of anything it always brings life to it?”

“Certainly,” he said.

“Is there anything that is the opposite of life?”

“Yes,” said he.

“What?”

“Death.”

“Now the soul, as we have agreed before, will never admit the opposite of that which it brings with it.”

“Decidedly not,” said Cebes.

[…]

“Well then what do we call that which does not admit death?”

“Deathless or immortal,” he said.

“And the soul does not admit death?”

“No.”

“Then the soul is immortal.”

[…]

“Necessarily,” he said. “And must not the same be said of that which is immortal? If the immortal is also imperishable, it is impossible for the soul to perish when death comes against it. For, as our argument has shown, it will not admit death and will not be dead, just as the number three, we said, will not be even, and the odd will not be even, and as fire, and the heat in the fire, will not be cold.”

In his first argument, the Argument from Opposites, Socrates posits that one opposite arises from its corresponding opposite in a perpetual cycle of generation and destruction. However, his Final Argument introduces a subtle shift in focus. He moves beyond a general discussion of opposites and emphasizes that certain things possess an essential characteristic that defines their nature. Fire, for example, is inherently hot; it cannot be cold without violating its essence.

Applying this principle to the soul, Socrates asserts that its defining characteristic is to enliven or bring life. Since death is the antithesis of life, the soul cannot experience death—just as fire cannot be cold. This intrinsic quality of the soul establishes its immortality. Furthermore, anything immortal is inherently indestructible. Thus, even when the body perishes, the immortal soul persists.

Connection

Transcending Mortality: Philosophical and Theological Perspectives

The Final Argument’s assertion of the soul’s immortality resonates with various theological and religious beliefs. The idea of a soul transcending the physical body and continuing after death is common in many spiritual practices. Christianity, Hinduism, and Buddhism, despite their differences, all embrace the concept of a transcendent aspect of human existence that persists beyond physical death. The Phaedo offers a philosophical perspective on this enduring human quest for meaning and transcendence, inviting contemplation on the connections between philosophical reasoning and spiritual beliefs.

The Final Hours: Finding Comfort in a Myth

Despite Socrates’ four arguments, his companions still doubt the soul’s immortality and life after death. To reassure them, he shares a comforting myth (107a-115a) that vividly depicts the afterlife, where souls are judged and assigned destinations based on their moral character during earthly life. Philosophical souls, embodying wisdom and virtue, ascend to a blissful realm where they live with the gods, while those corrupted by vice are condemned to Tartarus. Even souls that are not entirely virtuous can seek redemption through punishment and reincarnation. In narrating this myth, Plato’s Socrates reaffirms his belief in the immortality of the soul and implies that, since he has led a virtuous life, he has nothing to fear. His death will only be the beginning of another, happier life next to the gods.

117b–c: 

[…]

without trembling or changing color or expression, but looking up at the man with wide open eyes, as was his custom, said: “What do you say about pouring a libation to some deity from this cup? May I, or not?” 

“Socrates,” said he, “we prepare only as much as we think is enough.” 

“I understand,” said Socrates; “but I may and must pray to the gods that my departure hence be a fortunate one; so I offer this prayer, and may it be granted.” With these words he raised the cup to his lips and very cheerfully and quietly drained it. 

The Phaedo concludes with the poignant scene of Socrates’ death, where his serene acceptance exemplifies his philosophical beliefs. Rather than ending with abstract arguments, the dialogue culminates in a vivid demonstration of Socrates’ principles. This powerful conclusion emphasizes that, for Socrates, philosophy is not merely theoretical but a lived reality, allowing one to confront death with equanimity.

Summary

In Plato’s Phaedo, Socrates’ final hours spark a profound exploration of the soul’s immortality. Through philosophical debate and a captivating myth, the dialogue explores the nature of the soul and its potential afterlife, leaving a lasting impact on our understanding of life, death, and the human spirit.

Video

Plato’s Phaedo

For an overview of Plato’s arguments regarding the immortality of the soul in the Phaedo and a general idea of his philosophical views on the subject, check out this video:

Want to Learn More?

To learn more about Plato’s perspective on the immortality of the soul, and how, based on its philosophical or non-philosophical previous life, a soul can experience happiness and rewards or sadness and punishments in the afterlife, keep on reading the Phaedo. For further information on the dialogue, check out this article on Plato’s Phaedo from the Internet Encyclopedia of Philosophy.

Acknowledgements

This work has been adapted from Plato, Phaedo, a title from Perseus Digital Library. This work is in the public domain. All images were created using Midjourney.

Citation

Giasoumi, Athanasia. 2025. “Exploring Immortality: Plato’s Phaedo.”  The Philosophy Teaching Library. Edited by Robert Weston Siscoe, <https://philolibrary.crc.nd.edu/article/exploring-immortality>

Key Concept

Unconditioned: an ultimate explanation of reality. For example, if I explain why it is raining today by appealing to some atmospheric conditions, I can always ask for the cause of those conditions, and so on. Only a cause that is not caused by anything else (something unconditioned) would give us an ultimate explanation.

Key Concept

Transcendental Idealism: Kant’s mature philosophical position. It holds that appearances are not things in themselves, but representations of our mind. It is opposed to transcendental realism, which identifies appearances with things in themselves.

Key Concept

Appearances (vs. things in themselves): things as they are experienced by us (also known as phenomena). They should be distinguished from things as they are independently of our experience (things in themselves or noumena).

Key Concept

Metaphysics: the study of what there is. Traditionally, metaphysics is divided into general metaphysics and special metaphysics. The former investigates the general features of reality and asks questions such as ‘What is possible?’. The latter studies particular kinds of being and asks questions such as ‘Does God exist?’ or ‘Is the soul immortal?’.

Key Concept

Reason: the faculty that knows a priori. Kant uses this term in a general sense (the knowing faculty as such) and in a specific sense (the faculty that demands ultimate explanations).

Key Concept

A priori: term denoting propositions that can be known independently from experience. For example, propositions such as ‘All bachelors are unmarried’ or ‘The whole is greater than its parts’ can be known without recourse to any experience.

Key Concept

Make sure not to think that ‘unjustified’ means ‘false.’ Even if they are true, the point is just that this would not be something that had been shown.

Key Concept

‘Absolute’ might be a confusing word, here. Socrates means that the geometers are not reasoning about their drawing of the square, for example, but of the square itself. They do not conclude that, for the square they drew, the area is equal to the square of a side – they conclude that this is true for squares as an intelligible object, or, as Plato would say, the Form of the square.

Key Concept

By ‘science’, Plato means to be talking about all rational disciplines, including mathematics.

Key Concept

The form of the beautiful has to be perfectly beautiful because all instances of beautiful things are explained by it, so it has to be responsible for the highest possible degrees of beauty possessed by anything. Moreover, it has no trace of ugliness in it.

Key Concept

The form of the beautiful has to be immaterial because all the many beautiful things do not share any material – that is, they are all made of different stuff.

Key Concept

Form (εἶδος / ἰδέα) – Intelligible, immaterial, perfect entities that explain the unity among the many things which share the feature named by the entity (e.g., Beauty, Squareness, Oddness). For example, think of a square. There might be many different squares, but they all share features like having four sides of equal length. So, the Form of Squareness would include all of those features that make something a square.

Key Concept

Guardian – This is the name Plato gives to the ruling class in his ideal city. Think of them as philosopher kings – they have complete control over the organization of the state. The Republic is partially about why Plato thinks they would be needed for an ideal system of government and what they would need to learn to do the job well.

Key Concept

Plato has previously argued that we are made up of different parts. The first part is the appetitive which is responsible for our desires for food, sex, and other bodily needs. Then there is the spirited part, which longs for fame and honor. Finally, he identifies the rational part, which discerns what is good and bad for us through reason. The parts can all come into conflict with one another, and managing their relations is what Plato thinks justice is all about.

Key Concept

Soul (ψῡχή) – What Greeks meant by this word is controversial. For now, think of it as the thing that makes you different from a rock or other objects, the thinking and experiencing part of you as well as the part of you that acts and makes decision. You might use the word ‘mind’ or ‘self’ to talk about this.

Key Concept

Virtue – Virtues are the character traits that make a person good. For example, most people consider courage and generosity to be virtues. English-speakers usually reserve the word ‘virtue’ for human beings, but in ancient Greek the word can be more comfortably applied to other beings as well.

Key Concept

Was it his burly physique, his wide breadth of wisdom, or his remarkable forehead which earned him this nickname?

Key Concept

Aporia – A Greek term for “being at a loss” or “clueless.” Socrates often questions people until they have no idea how to define something that they thought they understood.

Key Concept

You might be confused by the word ‘attention’ below. In Greek the word is therapeia, from which we get the English word ‘therapy.’ It primarily means the same as ‘service’ as in ‘to serve,’ but shades into ‘worship,’ ‘take care of,’ and ‘attend to.’

Key Concept

Meletus – A poet and citizen of Athens and one of Socrates’ accusers. Amongst other things, Meletus accused Socrates of impiety and corrupting the youth.

Key Concept

Divine Voluntarism – The idea that God is free to determine even the most basic truths. If divine voluntarism is true, then God could have made it so that 2+2=5 or so that cruelty and blasphemy are holy and good.

Key Concept

Euthyphro Dilemma – The question, “Is a thing holy because the gods love it, or do the gods love it because it is holy?” The general idea of a forced choice (or “dilemma”) about the true order of explanation occurs often in philosophy and gets referred to by this term.

Key Concept

Essence – What a thing fundamentally is. A square might be red or blue without changing the fact that it’s a square, but a square must have four sides, so having four sides is part of a square’s essence.

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Definition – The perfect description of a thing. A definition should pick out all and only examples of a thing. For example, ‘bachelor’ might be defined as ‘unmarried man,’ because all unmarried men are bachelors, and only unmarried men are bachelors.

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In Disney’s retelling of the Hunchback of Notre Dame, the clergyman Claude Frollo orders the death of many Roma on religious grounds. It is clear, however, that he is really motivated by spite and his unrequited lust for the Romani woman Esmerelda.

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Spanish conquistadors were shocked by the scope of ritual human sacrifice among the Aztecs, as hundreds or even thousands of people were sacrificed each year. The Aztecs thought that the sacrifices could repay the sacrifices the gods had made in creating the sun and earth.

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Zeus – The god of sky and thunder in ancient Greek mythology, Zeus was depicted as chief among the gods and called the father of the gods and men.