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7 philosophy books that shaped Western thought

Dive into seven texts that continue to shape Western philosophy, from ancient Mesopotamia to Greece’s brightest minds.
An influential philosophy book featuring a bearded man on its portrait.
Pictured: title page of the oldest complete manuscript of Plato's 'The Republic,' Paris, Bibliothèque Nationale, Gr. 1807 (late 9th century). / Wikimedia Commons
Key Takeaways
  • These seven philosophical texts have shaped the contours of Western thought, delving into questions of justice, existence, and human nature.
  • While celebrated works such as Plato’s Republic offer insights into justice and reality, lesser-known pieces like the Mesopotamian Dialogue of Pessimism illuminate ancient perspectives on life’s absurdities.
  • Collectively, these writings underscore the rich tapestry of ideas that have laid the foundation for contemporary philosophical discourse.

Books possess a unique magic: With only ink and paper, they can communicate thoughts from a person who is separated from you by thousands of years and unfathomable cultural space. For some particularly original thinkers, this has allowed mere fragments of text to influence the course of human thought for thousands of years. The following seven influential philosophy books have helped shape the intellectual history of the Western world and, more recently, the entire planet.

Dialogue of Pessimism — Unknown author

Ancient Greece is the culture most associated with philosophy. However, it is wrong to think that nobody else studied it. Plato himself wrote about Egypt’s long philosophical history, for example. Unfortunately, however, there is precious little surviving philosophy that originated across the rest of the Mediterranean and Mesopotamian worlds. 

One of the surviving texts is the Dialogue of PessimismIt exists in two similar forms: one Assyrian and one Babylonian. While parts of both are fragmentary, it is the best-preserved example of Mesopotamian “wisdom texts.” Framed as a dialogue between two characters, an Aristocrat and his Slave, the text consists of the Aristocrat proposing ideas for things to do to the Slave, who provides good reasons for them. The Aristocrat then proposes opposing ideas, yet the Slave is just as easily able to defend those. The last few lines reflect on the absurdity of life. Many interpretations of this exist. Some suggest it is a precursor to modern existentialist thought, particularly that of Camus or Søren Kierkegaard. It is easy to see that from the final lines of the text: 

“Slave, listen to me!
Here I am, master, here I am! 
What then is good? To have my neck and yours broken, or to be thrown into the river, is that good? 
Who is so tall as to ascend to heaven? Who is so broad as to encompass the entire world? 
 O well, slave! I will kill you and send you first! 
 Yes, but my master would certainly not survive me for three days!”

Babylonian thought is so foundational that its influence is often overlooked. We still use Babylonian units to measure time. Their astronomers laid the foundations for both modern astronomy and science itself. And it is speculated that many Greek thinkers, such as Thales, were influenced by Babylonian thought. The Dialogue of Pessimism is thought to have influenced biblical texts, particularly Ecclesiastes, and can be viewed as a forerunner of Plato’s Socratic Dialogues

Poems — Xenophanes

The first pre-Socratic philosopher with a considerable amount of extant writing samples for us to review is Xenophanes. Unlike many of his contemporaries, he wrote many different books and poems. Enough fragments of his work survive to give us something beyond later commentary. While a full picture of his thoughts is impossible to form, what does exist demonstrates why he was one of the most influential pre-Socratic philosophers. 

Xenophanes is principally known for his theology. He argued that common conceptions about the gods in the Greek world were mistaken. His view of God was spherical: lacking human traits, and perhaps directly identifiable with the Universe. While there is some debate around his exact wording, he may have been the first Western monotheist, or arguably even pantheist. He mused that humans tended to give their gods familiar traits:

“Thracians that theirs are blue-eyed and red-haired. But if horses or oxen or lions had hands or could draw with their hands and accomplish such works as men, horses would draw the figures of the gods as similar to horses, and the oxen as similar to oxen, and they would make the bodies of the sort which each of them had.”

His principal philosophical legacy lies in his approach to epistemology and skepticism. While he argued for the existence of objective truths, he doubted the ability of humans to ascertain them. He noted that our beliefs were limited by our knowledge and used this as evidence for how little we can truly know:

 “If god had not made yellow honey [we] would think that figs were much sweeter.”

The skeptics of the ancient world would claim him as a critical influence. However, recent interpretations lean toward Xenophanes’ warning against dogmatic approaches or claims to certainty rather than a hard-line skeptic position. In either case, his writings are among the first to consider the problem of how we can claim to know anything — a problem people still grapple with today. 

On Nature — Parmenides

Parmenides is one of the most important ancient philosophers you’ve never heard about. Working in Elea, a Greek colony in what is now southern Italy, he wrote a single book that exists only in fragmented quotations and later authors’ commentaries. Through these, he has impacted virtually all subsequent Western philosophy. 

While the name was probably a later inventionOn Nature was a commonly applied name for works describing the Universe — Parmenides’ poem is one of the most important texts in Greek philosophy. In it, he invented metaphysics and contributed to logic by laying out his arguments with deductive rigor. Unlike his predecessors — famed for arguing that the world was made of a single, physical element — Parmenides argued that the world is a single, unchanging substance and that our notions of motion, change, creation, and destruction are all mistaken. The world we interact with is not the “true” reality but only a set of appearances. He also maintains that empty space is impossible since the idea of “nothing” is contradictory. 

 In his words:

 “…the only routes of inquiry that are for thinking: the one, that it is and that it is not possible for it not to be, is the path of Persuasion (for it attends upon Truth), the other, that it is not and that it is right that it not be, this indeed I declare to you to be a path entirely unable to be investigated: For neither can you know what is not (for it is not to be accomplished) nor can you declare it. For the same thing is for thinking and for being.”

Parmenides’ legacy is vast. His work directly influenced Plato, who argued that the world we engage with is a mere copy of the world of “forms.” Through Plato, Parmenides impacted nearly all of subsequent Western philosophy. His ideas on time and space continue to influence modern debates. 

Discourses of Epictetus — Flavius Arrian 

Epictetus was a Stoic philosopher in the Roman Empire during the second century. Born in what is now Turkey, he was enslaved and owned by Emperor Nero’s secretary at one point. While in servitude, he began receiving an education in Stoic philosophy from Musonius Rufus. After his freedom was restored, he was banished to Greece, where he founded a well-regarded school. Known for teaching Stoicism as a way of life rather than just a pure philosophy, he was well-known in his day — some sources suggest he was more famous than Plato was during his lifetime

Discourses is a series of polished notes from post-lecture discussions. It was likely written by his student, Flavius Arrian. While the exact length of the original text remains unknown, some sources suggest there were eight books in the complete set. Today we have four. These cover a wide range of topics relatable to anyone at any time and present Stoicism as a guide to life rather than a dry philosophy. One of the more famous quotes expresses why a person should bother to study at all:

 “For on these matters we should not trust the multitude who say that none ought to be educated but the free, but rather to philosophers, who say that the educated alone are free.”

Discourses is one of the earliest records we have of the thoughts of a Stoic thinker. Marcus Aurelius held it in high regard and quoted it in Meditations. It was also the source for The Handbook, an introduction to Stoic philosophy aimed at popular audiences, also likely penned by Arrian. This book has proven popular, especially during increases in the popularity of Stoic thought.

Republic — Plato

Plato’s Republic is arguably one of the most famous works in philosophy. Framed as a discussion between Socrates and several others about the nature of justice, it provides us with some of the most enduring philosophical arguments and images. 

Socrates addresses the idea of justice by analogy, using the concept of a “just city” to understand how justice impacts the soul. His perfect city has attracted a great deal of attention over the millennia. Along the way, he considers how acquiring knowledge is like leaving a dark cave, what exactly love is, the differences between reality and the world we engage with, and what would happen if you gave a man a magic ring that turned him invisible. 

Many lines from Republic have become widely known. One particularly famous example is:

“The punishment which the wise suffer who refuse to take part in the government, is to live under the government of worse men.”

The influence of Republic cannot be overstated. It has influenced thinkers from Plato’s student Aristotle to those working in the field today. It remains the most widely read book at American Universities. The “utopia” it describes has been used as a framework for the eponymous book. It has also been argued, but not proven, that Plato’s Ring of Gyges may have influenced Tolkien’s One Ring. 

The Nicomachean Ethics Aristotle

One of the most important books on ethics ever written — The Nicomachean Ethics — is Aristotle’s attempt to determine what the good life is and how to live it. 

His answer is a system of virtue ethics. His notion of virtue is that of a median point between two vices. For example, courage is seen as the midpoint between the vices of rashness and cowardice. Exactly what these things look like at the moment will vary, meaning that virtue requires serious study, practice, and work. He admits this and goes so far as to suggest that a good life requires making habits of the virtues so they can be practiced regularly. This is entirely needed, because, as he puts it:

“…one swallow does not make a summer, nor does one day; and so too one day, or a short time, does not make a man blessed and happy.”

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While other systems eclipsed Aristotelian Ethics in popularity, virtue ethics is currently enjoying a major resurgence in popularity. Philosophers are reconsidering virtue ethics to avoid the problems in utilitarian and deontological ethical systems. 

Lives and Opinions of the Eminent Philosophers — Diogenes Laërtius

The last inclusion on this list is the strangest. The Lives and Opinions of the Eminent Philosophers is a text by Diogenes Laërtius, written in the 3rd century C.E. The book covers many famous Greek philosophers’ personal lives and ideas. Modern scholars tend to agree that it is not the most reliable source, that its author tends to focus on minor details to the detriment of telling us what his subjects thought, and that the contradictions in it make it clear that parts of it must be wrong.

While on its own merits, the book might be considered of limited value, it’s crucial when considering the loss of many primary ancient texts. Diogenes Laërtius documented the lives and thoughts of Greek philosophers without much critique, offering a likely unbiased glimpse into their worlds. Our modern understanding of many Greek philosophers owes much to this text, making it indispensable in the study of ancient thought.

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