Primary Sources – Ancient & Medieval Philosophy


Fragments of Anaxagoras

Anaxagoras of Clazomenae (500 BC-428 BC) was reportedly the first Presocratic philosopher to settle in Athens. He was a friend of Pericles and his ideas are reflected in the works of Sophocles and Aristophanes. Anaxagoras asserted that Mind is the ordering principle of the cosmos, he explained solar eclipses, and he wrote on a myriad of astronomical, meteorological, and biological phenomena. His metaphysical claim that everything is in everything and his rejection of the possibility of coming to be or passing away are fundamental to all his other views. Because of his philosophical doctrines, Anaxagoras was condemned for impiety and exiled from Athens.


Summa Contra Gentiles by Thomas Aquinas

The Summa Contra Gentiles is not merely the only complete summary of Christian doctrine that St. Thomas has written, but also a creative and even revolutionary work of Christian apologetics composed at the precise moment when Christian thought needed to be intellectually creative in order to master and assimilate the intelligence and wisdom of the Greeks and the Arabs. In the Summa Aquinas works to save and purify the thought of the Greeks and the Arabs in the higher light of Christian Revelation, confident that all that had been rational in the ancient philosophers and their followers would become more rational within Christianity. This exposition and defense of divine truth has two main parts: the consideration of that truth that faith professes and reason investigates, and the consideration of the truth that faith professes and reason is not competent to investigate.


The Complete Works of Aristotle

Aristotle was an ancient Greek philosopher and scientist born in the city of Stagira, Chalkidiki, in the north of Classical Greece. Along with Plato, he is considered the “Father of Western Philosophy”. Aristotle provided a complex and harmonious synthesis of the various existing philosophies prior to him, including those of Socrates and Plato, and it was above all from his teachings that the West inherited its fundamental intellectual lexicon, as well as problems and methods of inquiry. As a result, his philosophy has exerted a unique influence on almost every form of knowledge in the West and it continues to be central to the contemporary philosophical discussion.


City of God by Augustine

St Augustine, bishop of Hippo, was one of the central figures in the history of Christianity, and City of God is one of his greatest theological works. Written as an eloquent defence of the faith at a time when the Roman Empire was on the brink of collapse, it examines the ancient pagan religions of Rome, the arguments of the Greek philosophers and the revelations of the Bible. Pointing the way forward to a citizenship that transcends the best political experiences of the world and offers citizenship that will last for eternity, City of God is one of the most influential documents in the development of Christianity.


Confessions by Augustine

The son of a pagan father and a Christian mother, Saint Augustine spent his early years torn between conflicting faiths and world views. His Confessions, written when he was in his forties, recount how, slowly and painfully, he came to turn away from his youthful ideas and licentious lifestyle, to become instead a staunch advocate of Christianity and one of its most influential thinkers. A remarkably honest and revealing spiritual autobiography, the Confessions also address fundamental issues of Christian doctrine, and many of the prayers and meditations it includes are still an integral part of the practice of Christianity today.


The Meditations by Marcus Aurelius

Few ancient works have been as influential as the Meditations of Marcus Aurelius, philosopher and emperor of Rome (A.D. 161–180). A series of spiritual exercises filled with wisdom, practical guidance, and profound understanding of human behavior, it remains one of the greatest works of spiritual and ethical reflection ever written. Marcus’s insights and advice—on everything from living in the world to coping with adversity and interacting with others—have made the Meditations required reading for statesmen and philosophers alike, while generations of ordinary readers have responded to the straightforward intimacy of his style. For anyone who struggles to reconcile the demands of leadership with a concern for personal integrity and spiritual well-being, the Meditations remains as relevant now as it was two thousand years ago.


The Consolation of Philosophy by Boethius

Boethius was an eminent public figure under the Gothic emperor Theodoric, and an exceptional Greek scholar. When he became involved in a conspiracy and was imprisoned in Pavia, it was to the Greek philosophers that he turned. The Consolation was written in the period leading up to his brutal execution. It is a dialogue of alternating prose and verse between the ailing prisoner and his ‘nurse’ Philosophy. Her instruction on the nature of fortune and happiness, good and evil, fate and free will, restore his health and bring him to enlightenment. The Consolation was extremely popular throughout medieval Europe and his ideas were influential on the thought of Chaucer and Dante.


The Dhammapada by Buddha

The Dhammapada is a collection of sayings of the Buddha in verse form and one of the most widely read and best known Buddhist scriptures. The original version of the Dhammapada is in the Khuddaka Nikaya, a division of the Pali Canon of Theravada Buddhism.

The Buddhist scholar and commentator Buddhaghosa explains that each saying recorded in the collection was made on a different occasion in response to a unique situation that had arisen in the life of the Buddha and his monastic community. His commentary, the Dhammapada Atthakatha, presents the details of these events and is a rich source of legend for the life and times of the Buddha.


The Vagrakkhedikâ Or Diamond-Cutter by Buddha

The Diamond Sūtra is a Mahāyāna (Buddhist) sūtra from the Prajñāpāramitā sutras or ‘Perfection of Wisdom’ genre. Translated into a variety of languages over a broad geographic range, the Diamond Sutra is one of the most influential Mahayana sutras in East Asia, and is particularly prominent within the Chan (or Zen) tradition, along with the Heart Sutra.

A copy of the Tang-dynasty Chinese version of the Diamond Sūtra was found among the Dunhuang manuscripts in 1907 by Daoist monk Wang Yuanlu on June 25, 1900, and sold to Aurel Stein. They are dated back to May 11, 868. It is, in the words of the British Library, “the earliest complete survival of a dated printed book.”

It is also the first creative work with an explicit public domain dedication, as its colophon at the end claims it was created “for universal free distribution.”


Discourses by Epictetus

The Enchiridion, or Manual by Epictetus

Epictetus was a crippled Greek slave of Phrygia during Nero’s reign (54-68 CE) who heard lectures by the Stoic Musonius before he was freed. Expelled with other philosophers by the emperor Domitian in 89 or 92 he settled permanently in Nicopolis in Epirus. There, in a school which he called ‘healing place for sick souls’, he taught a practical philosophy, details of which were recorded by Arrian, a student of his, and survive in four books of Discourses and a smaller Enchiridion, a handbook which gives briefly the chief doctrines of the Discourses. He apparently lived into the reign of Hadrian (117-138 CE).


Letter to Menoeceus by Epicurus

Principal Doctrines by Epicurus

Epicurus was an ancient Greek philosopher who founded a highly influential school of philosophy now called Epicureanism. He was born on the Greek island of Samos to Athenian parents. Influenced by Democritus, Aristotle, and possibly the Cynics, he turned against the Platonism of his day and established his own school, known as “the Garden”, in Athens. He and his followers were known for eating simple meals and discussing a wide range of philosophical subjects, and he openly allowed women to join the school as a matter of policy. An extremely prolific writer, he is said to have originally written over 300 works on various subjects, but the vast majority of these writings have been lost. Only three letters written by him—the Letters to Menoeceus, Pythocles, and Herodotus—and two collections of quotes—the Principle Doctrines and the Vatican Sayings—have survived intact, along with a few fragments and quotations of his other writings. His teachings are better recorded in the writings of later authors, including the Roman poet Lucretius, the philosopher Philodemus, the philosopher Sextus Empiricus, and the biographer Diogenes Laërtius.


In Praise of Folly by Desiderius Erasmus

Erasmus of Rotterdam (c. 1466-1536) is one of the greatest figures of the Renaissance humanist movement, which abandoned medieval pieties in favour of a rich new vision of the individual’s potential. Praise of Folly, written to amuse his friend Sir Thomas More, is Erasmus’s best-known work. Its dazzling mixture of fantasy and satire is narrated by a personification of Folly, dressed as a jester, who celebrates youth, pleasure, drunkenness and sexual desire, and goes on to lambast human pretensions, foibles and frailties, to mock theologians and monks and to praise the ‘folly’ of simple Christian piety. Erasmus’s wit, wordplay and wisdom made the book an instant success.


Fragments of Heraclitus

Heraclitus (535 – 475 BC) was a pre-Socratic Greek philosopher, and a native of the city of Ephesus, then part of the Persian Empire. He was famous for his insistence on ever-present change as being the fundamental essence of the universe, as stated in the famous saying, “No man ever steps in the same river twice”. This is commonly considered to be one of the first digressions into the philosophical concept of becoming, and has been contrasted with Parmenides statement that “what-is is” as one of the first digressions into the philosophical concept of being. As such, Parmenides and Heraclitus are commonly considered to be two of the founders of ontology.


On Aristotle’s Categories by Ammonius Hermiae

Ammonius Hermiae (AD 440 – 520) was a Greek philosopher, and the son of the Neoplatonist philosophers Hermias and Aedesia. He was a pupil of Proclus in Athens, and taught at Alexandria for most of his life, writing commentaries on Plato, Aristotle, and other philosophers.


Tao Te Ching by Lao-Tzu

The Tao Te Ching is a Chinese classic text traditionally credited to the 6th-century BC sage Lao-Tzu. The Tao Te Ching, along with the Zhuangzi, is a fundamental text for both philosophical and religious Taoism. It also strongly influenced other schools of Chinese philosophy and religion, including Legalism, Confucianism, and Buddhism, which was largely interpreted through the use of Taoist words and concepts when it was originally introduced to China. Many Chinese artists, including poets, painters, calligraphers, and gardeners, have used the Tao Te Ching as a source of inspiration. Its influence has spread widely outside East Asia and it is among the most translated works in world literature.


Essays of Michel de Montaigne

With the goal of describing man with complete frankness and using himself as his most frequent example, Michel de Montaigne first published his “Essays” in 1580. This collection of essays encompasses a wide variety of subjects, originally inspired by his study of Latin classics, and later by the lives of the leading figures of his time. Michel de Montaigne saw the most basic elements of man as variety and unpredictability, and this idea permeates the entire work, even as he explores a myriad of topics, including theology, philosophy, law, fame, memory, death, and his own daily schedule. The longest essay, entitled ‘Apology for Raymond Sebond,’ contains his most famous quote: “What do I know?” This perhaps embodies the spirit of the entire volume, for it reflects both the inquisitory search for intellectual knowledge as well as the more personal anecdotal quality of a work that has had an enduring impact on both French and English literature for hundreds of years.


Fragments and Commentary of Parmenides

Parmenides (late sixth or early fifth century BC) was a pre-Socratic Greek philosopher from Elea in Magna Graecia (Greater Greece, which included Southern Italy). He was the founder of the Eleatic school of philosophy. The single known work by Parmenides is a poem, On Nature, only fragments of which survive. In it, Parmenides prescribes two views of reality. In “the way of truth” (a part of the poem), he explains how reality (coined as “what-is is”) is one, change is impossible, and existence is timeless, uniform, necessary, and unchanging. This is generally considered one of the first digressions into the philosophical concept of being, and has been contrasted with Heraclitus’s statement that “No man ever steps into the same river twice” as one of the first digressions into the philosophical concept of becoming.


The Complete Works of Plato

Plato (424 – 348 BC) was a philosopher in Classical Greece and the founder of the Academy in Athens, the first institution of higher learning in the Western world. He is widely considered the pivotal figure in the development of Western philosophy. Unlike nearly all of his philosophical contemporaries, Plato’s entire work is believed to have survived intact for over 2,400 years.

Along with his teacher, Socrates, and his most famous student, Aristotle, Plato laid the foundations of Western philosophy and science. Alfred North Whitehead once noted: “the safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato.” In addition to being a foundational figure for Western science, philosophy, and mathematics, Plato has also often been cited as one of the founders of Western religion and spirituality.


Enneads by Plotinus

The Enneads is the collection of writings of Plotinus, edited and compiled by his student Porphyry (270 AD). Plotinus was a student of Ammonius Saccas and they were founders of Neoplatonism. His work, through Augustine of Hippo, the Cappadocian Fathers, Pseudo-Dionysius the Areopagite and several subsequent Christian and Muslim thinkers, has greatly influenced Western and Near-Eastern thought. In his philosophy, described in the Enneads, there are three principles: the One, the Intellect, and the Soul.


The Morals of Plutarch

Plutarch (46-120 CE) was something like a celebrity in Ancient Rome. Born in Boetia, a place thought to produce dim-witted men, Plutarch truly defied the regional superstition. He was a celebrated historian, essayist, biographer, and mayor. He travelled all over the Mediterranean, but lived most of his life in Chaeronea. Just twenty miles from his home, he held the position of senior priest at the storied Oracle of Delphi, and translated the prophecies of Pythia. He wrote many biographies, as well as philosophical and moral essays that have hugely impacted English and French literature. His influence is seen in the works of Shakespeare, Emerson, and Montaigne, among so many others. Contained here are a collection of his essays on morality.


A Presocratics Reader: Selected Fragments and Testimonia

Ideal for a two-to-three week introduction to the Presocratics and Sophists, this volume offers a selection of the extant remains of early Greek philosophical thought on cosmology, metaphysics, epistemology, and ethics, together with unobtrusive, minimally interpretive editorial material: an introduction, brief headnotes, maps, and a concordance.


Fragments and Commentary by Pythagoras

Pythagoras of Samos (570 – 495 BC) was an ancient Ionian Greek philosopher and the eponymous founder of Pythagoreanism. His political and religious teachings were well known in Magna Graecia and influenced the philosophies of Plato, Aristotle, and, through them, Western philosophy. The teaching most securely identified with Pythagoras is metempsychosis, or the “transmigration of souls”, which holds that every soul is immortal and, upon death, enters into a new body. He may have also devised the doctrine of musica universalis, which holds that the planets move according to mathematical equations and thus resonate to produce an inaudible symphony of music.


Ethics by Baruch Spinoza

Published shortly after his death, the Ethics is undoubtedly Spinoza’s greatest work – an elegant, fully cohesive cosmology derived from first principles, providing a coherent picture of reality, and a guide to the meaning of an ethical life. Following a logical step-by-step format, it defines in turn the nature of God, the mind, the emotions, human bondage to the emotions, and the power of understanding – moving from a consideration of the eternal, to speculate upon humanity’s place in the natural order, the nature of freedom and the path to attainable happiness. A powerful work of elegant simplicity, the Ethics is a brilliantly insightful consideration of the possibility of redemption through intense thought and philosophical reflection.


On the Improvement of Understanding by Baruch Spinoza

Spinoza commenced this treatise with the intention of examining the problem of knowledge, but the work was never completed. In his other works, epistemological discussions are intimately linked with the rest of his philosophy. Indeed, even in On the Improvement of Understanding epistemological views are almost inseparably connected with ethical ones. That is the consequence of his characteristic conception of knowledge. For Spinoza “knowledge” is “life”, not in the sense that contemplation is the highest life, but in the sense that knowledge is the means of holding together the threads of life in a systematic unity that can fill its proper place in the cosmic system.


Fragments and Commentary of Thales of Miletus

Thales of Miletus (624 – c. 546 BC) was a pre-Socratic Greek philosopher, mathematician, and astronomer from Miletus in Asia Minor (present-day Milet in Turkey). Many, most notably Aristotle, regarded him as the first philosopher in the Greek tradition, and he is otherwise historically recognized as the first individual in Western civilization known to have entertained and engaged in scientific philosophy. Thales is recognized for breaking from the use of mythology to explain the world and the universe, and instead explaining natural objects and phenomena by theories and hypotheses, in a precursor to modern science. Almost all the other pre-Socratic philosophers followed him in explaining nature as deriving from a unity of everything based on the existence of a single ultimate substance, instead of using mythological explanations.


On Moral Characters by Theophrastus

Theophrastus (371 – 287 BC), a Greek native of Eresos in Lesbos, was the successor to Aristotle in the Peripatetic school. He came to Athens at a young age and initially studied in Plato’s school. After Plato’s death, he attached himself to Aristotle who took to Theophrastus his writings. When Aristotle fled Athens, Theophrastus took over as head of the Lyceum. Theophrastus presided over the Peripatetic school for thirty-six years, during which time the school flourished greatly. He is often considered the father of botany for his works on plants. After his death, the Athenians honored him with a public funeral. His successor as head of the school was Strato of Lampsacus.

The interests of Theophrastus were wide-ranging, extending from biology and physics to ethics and metaphysics. His two surviving botanical works, Enquiry into Plants (Historia Plantarum) and On the Causes of Plants, were an important influence on Renaissance science. There are also surviving works On Moral Characters, On Sense Perception, On Stones, and fragments on Physics and Metaphysics. In philosophy, he studied grammar and language and continued Aristotle’s work on logic. He also regarded space as the mere arrangement and position of bodies, time as an accident of motion, and motion as a necessary consequence of all activity. In ethics, he regarded happiness as depending on external influences as well as on virtue.


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