Aristotelianism

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The treatises that carry Aristotle’s name are not books in any ordinary sense. They are terse, elliptical, full of abrupt transitions and cross-references to lectures now lost; in places they read like the bones of a course with the flesh stripped away. For two thousand years readers have taken these working papers of a school and built cathedrals of argument on them — and the strangest fact of the whole tradition is that the polished works Aristotle published in his lifetime, the dialogues praised by Cicero for their “golden river” of prose, are the ones that vanished. What survived was the scaffolding. What perished was the building.

Bust of Aristotle, Roman marble copy after a lost bronze attributed to Lysippos (c. 330 BCE), Palazzo Altemps, Rome. — Photo by Jastrow, via Wikimedia Commons (public domain).

The walk, the school, the lost library

Aristotle was born at Stagira in 384 BCE and died at Chalcis in 322. He spent close to twenty years inside Plato’s Academy, long enough to absorb its questions and to turn against several of its answers (the outline of his life and thought is surveyed in the Stanford Encyclopedia), and after a decade of travel and a stint tutoring the young Alexander he returned to Athens in 335 BCE and founded his own school in a grove sacred to Apollo Lyceios — the Lyceum. The members came to be called Peripatetics, the “walkers,” from the covered walk, the peripatos, along which the master was said to teach on the move. The name fixed an image: philosophy as something done on one’s feet, in passing, between one observation and the next.

What set the Lyceum apart from the Academy was its appetite for the particular. Aristotle and his students collected constitutions, dissected animals, cataloged plants, recorded the opinions of earlier thinkers as data to be sifted. The school was, among other things, the first research institute in the Western record — a place where knowing meant gathering before it meant deducing. When Aristotle withdrew from Athens in 323, fleeing a charge of impiety so that the city, in his reported phrase, would not sin twice against philosophy, the leadership passed to Theophrastus, who held the school from 322 until his own death around 287 BCE. Under Theophrastus the Peripatetic project of empirical inquiry reached its height; his Enquiry into Plants founded botany, and his Characters sketched the moral types of Athens with a dry precision that has never quite gone out of print.

Then the corpus nearly disappeared. Theophrastus willed the library — Aristotle’s writings among it — to a certain Neleus of Scepsis, who carried the books home to a small town in the Troad. There, according to the story told by Strabo and Plutarch, they were hidden in a cellar to keep them from the book-hungry kings of Pergamon, and lay neglected for generations, gnawed by damp and worms. Only when the Roman general Sulla sacked Athens in 86 BCE and seized a copy made by the bibliophile Apellicon did the treatises return to circulation. The scholarly consensus treats the cellar legend with caution — the school could hardly have lost all access to its founder’s thought for two centuries — but it agrees on the outcome. In the first century BCE, Andronicus of Rhodes, counted as the eleventh head of the Peripatos, produced the edition that fixed the corpus into the order we still use: grouping the treatises by subject, prefixing tables, and giving the collection the shape that every later reader inherited. The Aristotle of history is, in a real sense, the Aristotle of Andronicus. (The textual transmission of the corpus is reconstructed in detail by the Stanford Encyclopedia; the career of Theophrastus is treated there as well.)

That edition enforced a distinction the school itself had drawn. The published dialogues, written for outsiders, were the exoteric works; the dense lecture treatises, meant for those already inside the walls, were the esoteric or akroamatic writings — the things “heard” within the school. The second-century satirist Lucian preserves the word esōterikos in just this technical sense. Only the inside texts survived. The tradition that bears Aristotle’s name is built entirely on what was never meant to be read alone.

What the treatises teach

Plato and Aristotle at the center of Raphael’s School of Athens (1509–11), Apostolic Palace, Vatican; Plato points upward to the Forms, Aristotle gestures level to the earth. — Via Wikimedia Commons (public domain).

At the root of the system lies a quarrel with Plato over where reality is located. Plato had set the truly real in a realm of Forms apart from the changing world. Aristotle brought it back down. For him the form of a thing is not elsewhere; it is in the thing, the principle that organizes its matter into what it is. A bronze sphere is matter (the bronze) given shape by form (the sphericity); a living body is matter informed by soul. This is hylomorphism — from hylē, matter, and morphē, form — and it governs everything below. Nothing in the natural world is bare stuff or naked structure; everything is the two fused, and to understand a thing is to grasp how its form actualizes its matter.

Change, on this account, is the passage from potency to act. The acorn is potentially an oak; the oak is the acorn’s potency made actual. Becoming is not the arrival of something from nowhere but the realization of a capacity already latent in the matter. To explain anything fully one must name its four causes: the material cause (what it is made of), the formal cause (what it is to be that thing), the efficient cause (what brought it about), and the final cause (the end, the telos, for the sake of which it exists). The fourth is the most Aristotelian. Nature does nothing in vain; each thing has a built-in tendency toward its proper completion, and the world is shot through with purpose that needs no purposer outside it.

The chain of motion, traced upward, cannot regress forever. It terminates in an unmoved mover — pure actuality with no admixture of potency, eternal, immaterial, moving the cosmos not by pushing but by being supremely desirable, as the object of love moves the lover without itself stirring. This being’s sole activity is thought, and since nothing is worthier of it than itself, it is noēsis noēseōs: thought thinking itself. Later monotheists would read this self-thinking actuality as a philosopher’s approach to God, and much of medieval theology is the long labor of bending it to that use.

The instrument for all such reasoning is logic. The six treatises later gathered as the Organon — the “tool,” a title the school’s editors supplied, since Aristotle held logic to be the instrument of every science rather than a science itself — run from the Categories (the basic kinds of being and predication) through On Interpretation, the two Analytics, the Topics, and the Sophistical Refutations. Their heart is the syllogism: an argument in which, certain things being posited, something else follows of necessity from them. From “all men are mortal” and “Socrates is a man” the conclusion “Socrates is mortal” is forced, not chosen. Aristotle sorted such inferences into figures and valid moods with a rigor that left formal logic essentially unchanged until the nineteenth century. Kant could still claim, fairly, that the discipline had neither advanced nor retreated since its founder closed it. (The structure of the syllogistic and its figures is laid out in the Internet Encyclopedia of Philosophy.)

In the De Anima, the soul is the first actuality of a living body — its form, not a ghost lodged inside it. A plant’s soul nourishes and grows; an animal’s also senses and moves; the human soul further reasons. Reason raised the hardest question in the whole corpus. In a single dense chapter Aristotle distinguishes a passive intellect from an active intellect that is “separable, unmixed, and impassive,” alone deathless and eternal. Whether this immortal mind belongs to each person or is one shared light shining into many would split the commentators for fifteen hundred years.

The ethics is of a piece with the physics. If every nature has a function, the good for any kind is the excellent performance of that function. The human function is rational activity, and so human flourishing — eudaimonia, often rendered “happiness” but closer to a whole life lived well — consists in the exercise of reason in accordance with virtue. Virtue itself is a settled disposition lying at a mean between two vices, one of excess and one of defect: courage between recklessness and cowardice, generosity between waste and stinginess. The mean is not a bland average but the right response, to the right degree, at the right time, found by the person of practical wisdom, phronēsis, who perceives in each situation what the rule cannot specify in advance. Character is built by habituation; one becomes just by doing just acts, as one becomes a builder by building. Ethics, for the Peripatetic, is not a code handed down but a craft of becoming the kind of person who acts well without having to deliberate at all.

The afterlife of a tool

Gustav Adolph Spangenberg, The School of Aristotle (1880s), a romantic vision of the Peripatos. — Via Wikimedia Commons (public domain).

The first great act of reception was commentary, and it began at home. Alexander of Aphrodisias, working around 200 CE, wrote line-by-line expositions so authoritative that the later Greek tradition called him simply “the Exegete,” the commentator without qualification. He read the active intellect as something divine entering from outside and concluded that the individual human mind, passive and material, perishes with the body — a reading of mortality that would echo down to the Renaissance. After him the Neoplatonist commentators of late antiquity, Porphyry and Simplicius and Philoponus among them, folded Aristotle into a curriculum that treated his logic as the gateway to Plato’s higher mysteries, harmonizing the two masters whom Raphael would later paint pointing in opposite directions. By way of Neoplatonism the Aristotle who reached the Middle Ages came already tinged with a metaphysics not entirely his own.

He reached it first in Arabic. Syriac-speaking Christian scholars rendered the logical works into their language, and from the eighth century the translators of Baghdad carried the corpus into Arabic, where it found readers who took it more seriously than any Greek had since Alexander. (The Arabic-to-Latin passage of the corpus is mapped by Dag Nikolaus Hasse.) Al-Farabi earned the title “the Second Teacher,” second only to Aristotle himself. Avicenna built from Aristotelian materials a metaphysics of being and essence so original that it became a tradition in its own right. And in twelfth-century Córdoba, Averroes — Ibn Rushd, 1126 to 1198 — devoted his life to recovering the genuine Aristotle from the Neoplatonic accretions, writing short, middle, and long commentaries on nearly the whole corpus. The Latin West would know him as nothing less than “the Commentator,” as it knew Aristotle as “the Philosopher”; Dante, who placed both among the virtuous pagans of Limbo, named him che ‘l gran comento feo, he who made the great commentary. Averroes revived in the West the doctrine he drew from Alexander and pressed further: that there is a single shared intellect for the whole human race, and personal immortality is an illusion of the imagination.

That doctrine was a bomb. When the full Aristotle — physics, metaphysics, De Anima, all of it — flooded into the Latin universities in the twelfth and thirteenth centuries through translations from Arabic and then from the Greek, it arrived with Averroes attached, and the package threatened the faith at three points: the eternity of the world against creation in time, the single intellect against the immortal individual soul, and a chain of necessary causes against divine freedom. Paris condemned the libri naturales as early as 1210. The conflict came to a head in the work of Thomas Aquinas, 1225 to 1274, whose vast synthesis took Aristotle as the natural framework of all knowledge and labored to show, point by point, that the Philosopher rightly understood was no enemy of Christian doctrine but its most powerful servant. Aquinas accepted hylomorphism, the four causes, the analysis of soul as form, and turned the unmoved mover into the first of his proofs for God — while insisting, against the Averroists in the Paris arts faculty, that each soul is the individual form of its own body and survives it.

Benozzo Gozzoli, Triumph of St Thomas Aquinas (c. 1471, Louvre): Aristotle and Plato flank the seated Aquinas while Averroes, turbaned, lies vanquished at his feet. — Via Wikimedia Commons (public domain).

The synthesis did not win unopposed. On the seventh of March 1277 — three years to the day after Aquinas died — Étienne Tempier, bishop of Paris, issued a sweeping condemnation of 219 propositions drawn from the radical Aristotelians of the arts faculty, with Siger of Brabant and the Averroist reading squarely in view. To teach, defend, or even listen without protest to the forbidden theses now carried automatic excommunication. Several of the condemned articles brushed against Aquinas himself. The deeper target was the claim that the world had to be as Aristotelian physics described it: Tempier asserted, against the necessitarian cosmos, that God in his absolute power could have made many worlds, or a void, or moved the heavens in a straight line, whatever the Philosopher’s principles allowed. Some historians have read 1277 as a liberation — by denying that nature was bound to Aristotle’s necessities, it loosened the grip of the system and cleared ground for later inquiry. Whether or not it lit a fuse, it marks the moment when the tradition’s authority first met an authority willing to overrule it. (The text and afterlife of the 1277 condemnation are examined by Hans Thijssen.)

For three centuries more, Aristotle remained the curriculum of Europe, his logic the discipline of every student, his physics the description of every falling stone. Then the framework broke. When Galileo dropped his weights and Newton wrote his laws, the four causes gave way to mathematical force, the final cause was banished from physics as an explanation that explained nothing, and the geocentric cosmos of nested spheres dissolved. To the makers of the new science, “Aristotelian” became a term of contempt for empty verbal subtlety. The Philosopher was not refuted so much as set aside; his questions were declared the wrong questions.

Beneath the official corpus a second, stranger Aristotle had been traveling the whole time. A tenth-century Arabic compilation of statecraft, medicine, astrology, and the secret virtues of stones circulated under his name as the Secret of Secrets, Sirr al-asrar; carried into Latin as the Secretum Secretorum by the thirteenth century, it became the most copied of all medieval works ascribed to him, surviving in hundreds of manuscripts, a handbook of arcane wisdom the Lyceum would not have recognized. Stranger still, a paraphrase of Plotinus — passages from the Enneads reworked in ninth-century Baghdad — circulated in Arabic as the Theology of Aristotle, and the misattribution did its quiet work: for centuries the most influential single source of Aristotle’s supposed mysticism was in fact the voice of his great rival’s heirs. The contested authorship is now settled; the text is Neoplatonic to its core. The occult Aristotle, like so much of the tradition, was largely the creature of his readers.

The framework that physics discarded did not die. In 1958 G. E. M. Anscombe argued in a brief, detonating essay that modern moral philosophy had lost its way by clinging to the language of moral law after dropping the lawgiver who alone made it intelligible, and that ethics should be rebuilt instead on the older ground of virtue and human flourishing. The challenge was taken up. Alasdair MacIntyre’s After Virtue in 1981, along with the work of Philippa Foot and Rosalind Hursthouse, made Aristotelian virtue ethics a living position in analytic philosophy once more — not a relic to be studied but a theory to be argued. Two and a half millennia after a man taught while walking in a grove sacred to Apollo, the question he asked — what is it for a human being to live well, given the kind of creature a human being is — is once again being asked in his terms.

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