Meteorology

Summary

Aristotle's Meteorology, in four books, studies 'things on high' (meteora) and much else besides: everything that happens in the region between the moon's sphere and the earth, together with the sea, rivers, earthquakes and, in Book IV, the way heat and cold work on matter. It begins by placing itself in a sequence. The Physics has treated motion and causes, On the Heavens the stars, On Generation and Corruption the elements and their changes; the Meteorology takes up events that are natural but 'less perfect' in order than the heavens, and it looks ahead to the books on animals and plants. The explanatory key of Books I to III is a theory of two exhalations rising from the earth under the sun's heat: a moist one, vapour, and a dry, smoky one. Vapour rising and cooling makes cloud, rain, dew, hoar frost, snow and hail. The dry exhalation, carried to the upper region and set alight by the heavens' motion, produces shooting stars and comets; Aristotle explains the Milky Way the same way. Moving horizontally it is wind; trapped inside the earth it causes earthquakes; forced out of cloud it makes thunder and lightning. Rivers, he argues, are not fed by one underground reservoir, as the myth in Plato's Phaedo claims, but by mountains that hold water like a saturated sponge. The sea's saltness comes from an earthy admixture, as urine and sweat carry the salty residue of undigested food, and he reports that evaporated salt water condenses fresh: 'This I know by experiment.' Book I closes with one of the work's most memorable arguments. Land and sea change places over immense spans of time, as rivers silt up and dry; Egypt, he argues, was built up by the Nile, and the shallowing of Lake Maeotis is measurable within sixty years. These changes follow cycles and do not mean the world is coming to be or passing away. Book III turns to optics, explaining halos, rainbows, mock suns and 'rods' as reflections of sight, and notes that the moon rainbow is so rare that he has seen only two in more than fifty years. Book IV, whose place in the work is debated, is an early chemistry: the hot and cold are active, the dry and moist passive, and processes such as ripening, boiling and putrefaction are defined by how a thing's own heat masters its moisture. Much of the physics is wrong, and the work's value for students lies elsewhere: in watching a careful mind gather reports, test rival theories, admit what puzzles him, and insist that a poetic phrase is not an explanation. For a classical Christian school it shows natural philosophy as patient attention to the created order, carried on by a pagan observer before the experimental method. The library attaches E. W. Webster's public-domain Oxford translation, divided into Books and Parts that follow the traditional chapters.

Plot or Argument

• Book I, Parts 1–3: the program and the regions

  Aristotle situates meteorology after the Physics, On the Heavens and On Generation and Corruption. He describes the cosmos below the moon as layered: fire (or a hot, dry exhalation) above, then air, water and earth. Against Anaxagoras he argues that the upper region is not filled with fire in the ordinary sense, and he introduces the two exhalations, moist vapour and dry smoke.

• Book I, Parts 4–8: shooting stars, comets and the Milky Way

  Shooting stars, 'chasms' and blood-red glows in the night sky are kindlings of the dry exhalation. Aristotle reviews the comet theories of Anaxagoras and Democritus, the Pythagoreans, and Hippocrates of Chios with his pupil Aeschylus, then argues that comets are fiery exhalations moved with the revolution of the heavens. He explains the Milky Way as a similar phenomenon on the largest scale, rejecting older accounts.

• Book I, Parts 9–13: the cycle of water, and rivers

  The sun draws up vapour, which cools and falls as rain, mist, dew, hoar frost, snow or hail, in a cycle Aristotle compares to a river flowing up and down. Rivers and springs come chiefly from mountains, which gather water like a saturated sponge; Aristotle catalogues rivers from Parnassus to the Caucasus to show their mountain sources.

• Book I, Part 14: land and sea exchange places

  Over long periods the sea retreats and advances as rivers silt up and dry. Egypt was formed by the Nile; Sesostris and later Darius abandoned a canal because the sea lay higher than the land; Lake Maeotis has visibly shallowed. Floods such as Deucalion's are local 'great winters' of a great year, and the universe as a whole does not come to be or perish.

• Book II, Parts 1–3: the sea

  Aristotle rejects the Phaedo's picture of a central reservoir, Tartarus, as the source of all waters, rejects Democritus' view that the sea is drying up, and dismisses Empedocles' 'sweat of the earth' as poetry. Saltness comes from an earthy, burnt-like admixture carried down in rain; evaporated salt water condenses fresh.

• Book II, Parts 4–9: winds, earthquakes, thunder and lightning

  Wind is the dry exhalation moving around the earth; Aristotle describes the wind-rose and the seasonal Etesian winds. Earthquakes occur when exhalation trapped underground is forced to move, as wind in the body produces tremors and spasms. Thunder is exhalation striking cloud, and lightning its kindling, seen before the thunder is heard though produced after it.

• Book III: hurricanes, halos, rainbows and minerals

  Hurricanes, whirlwinds and thunderbolts are denser outbursts of exhalation. Halos, the rainbow, mock suns and rods are explained as reflections of sight from cloud and droplets, with geometrical arguments about the rainbow's shape and the order of its colours. The book ends by deriving 'fossiles' (minerals) from the dry exhalation and metals from the vaporous one, trapped within the earth.

• Book IV: the active and passive qualities

  Hot and cold act; dry and moist are acted upon. Concoction, by a thing's proper heat, has the species ripening, boiling and broiling; inconcoction, from deficient heat, the species rawness, imperfect boiling and imperfect broiling. Aristotle treats putrefaction, solidifying and melting, and the properties of 'homogeneous' bodies such as flesh, bone, metals and wood, concluding that what a thing is depends on its function.

Characters

• Anaxagoras of Clazomenae, predecessor examined

  Criticised for calling the upper region fire, and for his theories of comets, the Milky Way, hail and earthquakes.

• Democritus of Abdera, predecessor examined

  Atomist whose views on comets, the Milky Way, earthquakes and a shrinking sea Aristotle reports and rejects.

• Hippocrates of Chios and Aeschylus, predecessors examined

  The mathematician Hippocrates (not the physician of Cos) and his pupil, who explained a comet's tail as a reflection of sight toward the sun.

• Empedocles, predecessor examined

  Poet-philosopher who called the sea 'the sweat of the earth', a phrase Aristotle allows to poetry but not to science.

• Plato (the Phaedo), predecessor examined

  The myth of Tartarus as the central source of all waters, from the Phaedo, is analysed and rejected in Book II, Part 2.

Lessons

• A metaphor is not an explanation

  When Empedocles called the sea 'the sweat of the earth', Aristotle granted that the phrase may satisfy a poem but said it fails as a scientific theory. The distinction runs through the Meteorology: Aristotle reports myths, poets and earlier philosophers with respect, then asks what each account actually explains and whether the facts agree. Students learn to love poetic language and still to ask, of any vivid phrase offered as an answer, what it claims and how one would know.

  • Why does Aristotle reject 'the sweat of the earth' as a theory while allowing it as poetry?
  • What does he propose instead to explain the saltness of the sea?
  • Find a modern phrase used as if it were an explanation. What would Aristotle ask of it?

• Deep time and the patience of observation

  In Book I, Part 14, Aristotle argues that land and sea exchange places over spans too long for any human memory, so that whole peoples forget how their country began. He builds the case from evidence he can gather: the Nile's silt, a failed canal to the Red Sea, ships that can no longer sail into Lake Maeotis as they did sixty years before. Whatever one thinks of his conclusions, the method shows how small, measured changes can support large inferences, and how limited one lifetime is as a vantage on nature.

  • What evidence does Aristotle give that Egypt was formed by the Nile?
  • Why does he deny that these changes show the world as a whole coming into being?
  • How do the limits of human memory shape what we can know about the past?

• Testing theories against the facts

  Aristotle's habit is to set out rival theories, then test each against what is observed. Against the Phaedo's single reservoir he objects that rivers would then flow up as much as down, and that every river is seen to end in the sea; he likens Democritus' prediction that the sea will dry up to one of Aesop's tales; on salt water he reports a small trial of his own. His conclusions are often mistaken, but students can see the shape of rational inquiry: state the view fairly, draw out its consequences, compare them with experience, and admit what remains obscure.

  • What objections does Aristotle raise to the theory of rivers in the Phaedo?
  • What does he claim to know 'by experiment' in Book II, Part 3, and how might he have tested it?
  • Which of Aristotle's explanations in this book do you think fails, and how would you show it?

• A thing is what it can do

  Book IV ends with a principle Aristotle applies far beyond chemistry: what a thing is depends on its function. A dead man's hand is a hand only in name, like a stone flute or a wooden saw; an eye is an eye when it can see. The claim links the study of matter to the study of living things and prepares for the biological works. It also invites reflection on the purposes of human faculties and on why we speak of a body after death as no longer quite the person.

  • What examples does Aristotle use in Book IV, Part 12, to show that a thing is defined by its function?
  • Why does he say function is hardest to see in fire and water and easiest in a hand or face?
  • Does the principle apply to a human being as a whole? What would a person's function be?

Context

The Meteorology belongs to Aristotle's sequence of works on nature and draws on a long Greek tradition of speculation about sky, sea and earth, from the Milesians through Anaxagoras and Democritus. It became the standard account of weather and the sublunary world for nearly two thousand years, transmitted in Greek commentaries by Alexander of Aphrodisias and Olympiodorus, adapted in Arabic, and translated into Latin in the twelfth and thirteenth centuries.

Composition

Books I to III are usually dated to Aristotle's mature period, around the 340s or 330s BC; references to a comet and to recent changes in Lake Maeotis are sometimes used to anchor the date, but no firm year can be fixed, and 'c. 340 BC' is conventional. Book IV differs in subject and style, and scholars debate whether it belongs to the Meteorology, follows On Generation and Corruption, or was written by a pupil. The library's text is E. W. Webster's translation for the Oxford Works of Aristotle (1923), transcribed by the MIT Internet Classics Archive.

Reception

Aristotle's pupil Theophrastus extended the study of weather signs and winds, and Seneca's Natural Questions engaged closely with the Aristotelian tradition. Medieval scholars, including Albertus Magnus, wrote commentaries on it, and Theodoric of Freiberg in the fourteenth century advanced the theory of the rainbow beyond Aristotle's. In 1637 Descartes published Les Météores as a deliberate replacement for the Aristotelian account. The modern word meteorology derives from this treatise's title. It was included in the Great Books of the Western World (2nd ed., 1990), volume 7.

Comparisons

• On the Heavens

  On the Heavens treats the eternal, perfectly circular motions above the moon; the Meteorology treats the irregular events below it. Reading them together shows Aristotle's two-tier cosmos, in which comets are not heavenly bodies at all but fires in the upper air, a view that held until Tycho Brahe's comet observations of 1577.

• On Generation and Corruption

  On Generation and Corruption derives the four elements from pairings of hot, cold, dry and moist; the Meteorology applies that theory to weather, and its Book IV develops the active and passive qualities into an account of concoction and solidification that some scholars think was written to follow the earlier treatise directly.

• The Last Days of Socrates

  The Phaedo, included in this collection, ends with Socrates' myth of Tartarus, a vast central mass of water feeding all rivers. Aristotle takes the myth as a physical theory and refutes it in Book II, Part 2, an instructive case of reading a mythic image literally and testing it as science.

• Natural History: A Selection

  Pliny the Elder's Book II gathers Roman-era reports on comets, winds, earthquakes and portents, often from Aristotelian sources but with far less concern for causes. The contrast shows the difference between a natural philosopher seeking explanations and an encyclopedist collecting marvels.

Quotes

Medical Lens

The Meteorology repeatedly reasons by analogy between the earth and the animal body, which makes it a useful source for Greek physiological assumptions. Sweat and urine are said to carry the salty residue of undigested food; tremors, throbbing, tetanus and spasms are described as movements of wind (pneuma) in the body and used to explain earthquakes; and Book IV's doctrine of concoction, the perfecting of moisture by a thing's proper heat, is applied to boils and phlegm as well as to fruit and cooking, echoing the Hippocratic language of coction. These passages are analogies within a theory of nature, not clinical descriptions, and the physiology they presuppose is that of Aristotle's time.

• Book II, Part 3

  Undigested residue of liquid food is salt and bitter; it is excreted in urine, which leaves a salt deposit in chamber-pots, and in sweat. Aristotle uses this to explain the saltness of the sea.

  Ancient Medicine
• Book II, Part 8

  Earthquakes compared to the tremors and throbbings caused by wind in the body, including the shudder after passing water; tetanus and spasms described as motions of wind too strong for many men to restrain.

  Ancient Medicine Epilepsy Seizures
• Book IV, Parts 2–3

  Concoction as the perfecting of moisture by natural heat; ripening extended to boils and phlegm, and rawness defined as imperfect concoction.

  Ancient Medicine Humoral Medicine
• Book IV, Part 12

  A dead man is a man only in name, and his hand a hand only in name; a thing is itself when it can perform its function.

  Death Dying

Creative Prompts

• Classroom

  Keep a two-week weather journal. For each day, record what you observe, then write Aristotle's explanation from Books I and II alongside a modern one, and note where his account fits your observations and where it fails.

• Essay

  Aristotle says a metaphor may satisfy a poem but not a scientific theory. Write an essay on when figurative language helps science and when it misleads, using Empedocles' 'sweat of the earth' as your starting point.

• Dialogue

  Write a conversation between Aristotle and Descartes about the rainbow, each defending his own explanation with the evidence he had.

• Poetry

  Write a short poem on the moon rainbow Aristotle saw only twice in fifty years, keeping to what he actually reports about its rarity and conditions.

Further Reading

• Natural Questions, Seneca

  A Roman Stoic treatment of meteorological phenomena that engages the Aristotelian tradition.

• On the Nature of Things, Lucretius

  Book VI offers an Epicurean rival account of thunder, earthquakes, the Nile flood and magnetism.

• The Rainbow: From Myth to Mathematics, Carl B. Boyer

  Traces rainbow theory from Aristotle through Theodoric of Freiberg and Descartes to Newton.

• Aristotle: A Very Short Introduction, Jonathan Barnes

  A concise account of Aristotle's life and the range of his inquiries.