Nous, sometimes equated to intellect or intelligence, is a term from classical philosophy for the faculty of the human mind necessary for understanding what is true or real. English words such as "understanding" are sometimes used, but three used philosophical terms come directly from classical languages: νοῦς or νόος, intellēctus and intellegentia. To describe the activity of this faculty, the word "intellection" is sometimes used in philosophical contexts, as well as the Greek words noēsis and noeîn; this activity is understood in a similar way to the modern concept of intuition. In philosophy, common English translations include "understanding" and "mind", it is often described as something equivalent to perception except that it works within the mind. It has been suggested that the basic meaning is something like "awareness". In colloquial British English, nous denotes "good sense", close to one everyday meaning it had in Ancient Greece. In Aristotle's influential works, the term was distinguished from sense perception and reason, although these terms are inter-related.
The term was already singled out by earlier philosophers such as Parmenides, whose works are lost. In post-Aristotelian discussions, the exact boundaries between perception, understanding of perception, reasoning have not always agreed with the definitions of Aristotle though his terminology remains influential. In the Aristotelian scheme, nous is the basic understanding or awareness that allows human beings to think rationally. For Aristotle, this was distinct from the processing of sensory perception, including the use of imagination and memory, which other animals can do; this therefore connects discussion of nous to discussion of how the human mind sets definitions in a consistent and communicable way, whether people must be born with some innate potential to understand the same universal categories in the same logical ways. Deriving from this it was sometimes argued in classical and medieval philosophy, that the individual nous must require help of a spiritual and divine type. By this type of account, it came to be argued that the human understanding somehow stems from this cosmic nous, however not just a recipient of order, but a creator of it.
Such explanations were influential in the development of medieval accounts of God, the immortality of the soul, the motions of the stars, in Europe, North Africa and the Middle East, amongst both eclectic philosophers and authors representing all the major faiths of their times. In early Greek uses, Homer used nous to signify mental activities of both mortals and immortals, for example what they have on their mind as opposed to what they say aloud, it was one of several words related to thought and perceiving with the mind. In pre-Socratic philosophy, it became distinguished as a source of knowledge and reasoning opposed to mere sense perception or thinking influenced by the body such as emotion. For example, Heraclitus complained that "much learning does not teach nous". Among some Greek authors, a faculty of intelligence known as a "higher mind" came to be considered as a property of the cosmos as a whole; the work of Parmenides set the scene for Greek philosophy to come and the concept of nous was central to his radical proposals.
He claimed that reality as the senses perceive it is not a world of truth at all, because sense perception is so unreliable, what is perceived is so uncertain and changeable. Instead he argued for a dualism wherein nous and related words describe a form of perception, not physical, but intellectual only, distinct from sense perception and the objects of sense perception. Anaxagoras, born about 500 BC, is the first person, known to have explained the concept of a nous, which arranged all other things in the cosmos in their proper order, started them in a rotating motion, continuing to control them to some extent, having an strong connection with living things. Amongst the pre-Socratic philosophers before Anaxagoras, other philosophers had proposed a similar ordering human-like principle causing life and the rotation of the heavens. For example, like Hesiod much earlier, described cosmic order and living things as caused by a cosmic version of love, Pythagoras and Heraclitus, attributed the cosmos with "reason".
According to Anaxagoras the cosmos is made of infinitely divisible matter, every bit of which can inherently become anything, except Mind, matter, but which can only be found separated from this general mixture, or else mixed into living things, or in other words in the Greek terminology of the time, things with a soul. Anaxagoras wrote: All other things partake in a portion of everything, while nous is infinite and self-ruled, is mixed with nothing, but is alone, itself by itself. For if it were not by itself, but were mixed with anything else, it would partake in all things if it were mixed with any. For it is the thinnest of all things and the purest, it has all know
The Iliad is an ancient Greek epic poem in dactylic hexameter, traditionally attributed to Homer. Set during the Trojan War, the ten-year siege of the city of Troy by a coalition of Greek states, it tells of the battles and events during the weeks of a quarrel between King Agamemnon and the warrior Achilles. Although the story covers only a few weeks in the final year of the war, the Iliad mentions or alludes to many of the Greek legends about the siege; the epic narrative takes up events prophesied for the future, such as Achilles' imminent death and the fall of Troy, although the narrative ends before these events take place. However, as these events are prefigured and alluded to more and more vividly, when it reaches an end the poem has told a more or less complete tale of the Trojan War; the Iliad is paired with something of a sequel, the Odyssey attributed to Homer. Along with the Odyssey, the Iliad is among the oldest extant works of Western literature, its written version is dated to around the 8th century BC.
In the modern vulgate, the Iliad contains 15,693 lines. According to Michael N. Nagler, the Iliad is a more complicated epic poem than the Odyssey. Note: Book numbers are in parentheses and come before the synopsis of the book. After an invocation to the Muses, the story launches in medias res towards the end of the Trojan War between the Trojans and the besieging Greeks. Chryses, a Trojan priest of Apollo, offers the Greeks wealth for the return of his daughter Chryseis, held captive of Agamemnon, the Greek leader. Although most of the Greek army is in favour of the offer, Agamemnon refuses. Chryses prays for Apollo's help, Apollo causes a plague to afflict the Greek army. After nine days of plague, the leader of the Myrmidon contingent, calls an assembly to deal with the problem. Under pressure, Agamemnon agrees to return Chryseis to her father, but decides to take Achilles' captive, Briseis, as compensation. Achilles furiously will go home. Odysseus takes a ship and returns Chryseis to her father, whereupon Apollo ends the plague.
In the meantime, Agamemnon's messengers take Briseis away. Achilles becomes upset, sits by the seashore, prays to his mother, Thetis. Achilles asks his mother to ask Zeus to bring the Greeks to the breaking point by the Trojans, so Agamemnon will realize how much the Greeks need Achilles. Thetis does so, Zeus agrees. Zeus sends a dream to Agamemnon. Agamemnon heeds the dream but first decides to test the Greek army's morale, by telling them to go home; the plan backfires, only the intervention of Odysseus, inspired by Athena, stops a rout. Odysseus confronts and beats Thersites, a common soldier who voices discontent about fighting Agamemnon's war. After a meal, the Greeks deploy in companies upon the Trojan plain; the poet takes the opportunity to describe the provenance of each Greek contingent. When news of the Greek deployment reaches King Priam, the Trojans respond in a sortie upon the plain. In a list similar to that for the Greeks, the poet describes their allies; the armies approach each other, but before they meet, Paris offers to end the war by fighting a duel with Menelaus, urged by his brother and head of the Trojan army, Hector.
While Helen tells Priam about the Greek commanders from the walls of Troy, both sides swear a truce and promise to abide by the outcome of the duel. Paris is beaten, but Aphrodite rescues him and leads him to bed with Helen before Menelaus can kill him. Pressured by Hera's hatred of Troy, Zeus arranges for the Trojan Pandaros to break the truce by wounding Menelaus with an arrow. Agamemnon rouses the Greeks, battle is joined. In the fighting, Diomedes kills many Trojans, including Pandaros, defeats Aeneas, whom Aphrodite rescues, but Diomedes attacks and wounds the goddess. Apollo warns him against warring with gods. Many heroes and commanders join in, including Hector, the gods supporting each side try to influence the battle. Emboldened by Athena, Diomedes wounds puts him out of action. Hector prevents a rout. Hector enters the city, urges prayers and sacrifices, incites Paris to battle, bids his wife Andromache and son Astyanax farewell on the city walls, rejoins the battle. Hector duels with Ajax, but nightfall interrupts the fight, both sides retire.
The Greeks agree to burn their dead, build a wall to protect their ships and camp, while the Trojans quarrel about returning Helen. Paris offers to return the treasure he took and give further wealth as compensation, but not Helen, the offer is refused. A day's truce is agreed for burning the dead, during which the Greeks build their wall and a trench; the next morning, Zeus prohibits the gods from interfering, fighting begins anew. The Trojans prevail and force the Greeks back to their wall, while Hera and Athena are forbidden to help. Night falls, they camp in the field to attack at first light, their watchfires light the plain like stars. Meanwhile, the Greeks are desperate. Agamemnon admits his error, sends an embassy composed of Odysseus, Ajax and two heralds to offer Briseis and extensive gifts to Achilles, who has be
Democritus was an Ancient Greek pre-Socratic philosopher remembered today for his formulation of an atomic theory of the universe. Democritus was born in Abdera, around 460 BC, although there are disagreements about the exact year, his exact contributions are difficult to disentangle from those of his mentor Leucippus, as they are mentioned together in texts. Their speculation on atoms, taken from Leucippus, bears a passing and partial resemblance to the 19th-century understanding of atomic structure that has led some to regard Democritus as more of a scientist than other Greek philosophers. Ignored in ancient Athens, Democritus is said to have been disliked so much by Plato that the latter wished all of his books burned, he was well known to his fellow northern-born philosopher Aristotle. Many consider Democritus to be the "father of modern science". None of his writings have survived. Democritus was said to be born in the city of Abdera in Thrace, an Ionian colony of Teos, although some called him a Milesian.
He was born in the 80th Olympiad according to Apollodorus of Athens, although Thrasyllus placed his birth in 470 BC, the date is more likely. John Burnet has argued that the date of 460 is "too early" since, according to Diogenes Laërtius ix.41, Democritus said that he was a "young man" during Anaxagoras's old age. It was said that Democritus's father was from a noble family and so wealthy that he received Xerxes on his march through Abdera. Democritus spent the inheritance which his father left him on travels into distant countries, to satisfy his thirst for knowledge, he traveled to Asia, was said to have reached India and Ethiopia. It is known that he wrote on Meroe, he himself declared that among his contemporaries none had made greater journeys, seen more countries, met more scholars than himself. He mentions the Egyptian mathematicians, whose knowledge he praises. Theophrastus, spoke of him as a man who had seen many countries. During his travels, according to Diogenes Laërtius, he became acquainted with the Chaldean magi.
"Ostanes", one of the magi accompanying Xerxes, was said to have taught him. After returning to his native land he occupied himself with natural philosophy, he traveled throughout Greece to acquire a better knowledge of its cultures. He mentions many Greek philosophers in his writings, his wealth enabled him to purchase their writings. Leucippus, the founder of atomism, was the greatest influence upon him, he praises Anaxagoras. Diogenes Laertius says, he may have been acquainted with Socrates, but Plato does not mention him and Democritus himself is quoted as saying, "I came to Athens and no one knew me." Aristotle placed him among the pre-Socratic natural philosophers. The many anecdotes about Democritus in Diogenes Laërtius, attest to his disinterest and simplicity, show that he lived for his studies. One story has him deliberately blinding himself, he was cheerful, was always ready to see the comical side of life, which writers took to mean that he always laughed at the foolishness of people.
He was esteemed by his fellow citizens, because as Diogenes Laërtius says, "he had foretold them some things which events proved to be true," which may refer to his knowledge of natural phenomena. According to Diodorus Siculus, Democritus died at the age of 90, which would put his death around 370 BC, but other writers have him living to 104, or 109. Popularly known as the Laughing Philosopher, the terms Abderitan laughter, which means scoffing, incessant laughter, Abderite, which means a scoffer, are derived from Democritus. To his fellow citizens he was known as "The Mocker". Most sources say that Democritus followed in the tradition of Leucippus and that they carried on the scientific rationalist philosophy associated with Miletus. Both were materialist, believing everything to be the result of natural laws. Unlike Aristotle or Plato, the atomists attempted to explain the world without reasoning as to purpose, prime mover, or final cause. For the atomists questions of physics should be answered with a mechanistic explanation, while their opponents search for explanations which, in addition to the material and mechanistic included the formal and teleological.
Greek historians consider Democritus to have established aesthetics as a subject of investigation and study, as he wrote theoretically on poetry and fine art long before authors such as Aristotle. Thrasyllus identified six works in the philosopher's oeuvre which had belonged to aesthetics as a discipline, but only fragments of the relevant works are extant; the theory of Democritus held that everything is composed of "atoms", which are physically, but not geometrically, indivisible. Of the mass of atoms, Democritus said, "The more any indivisible exceeds, the heavier it is". However, his exact position o
The Universe is all of space and time and their contents, including planets, stars and all other forms of matter and energy. While the spatial size of the entire Universe is unknown, it is possible to measure the size of the observable universe, estimated to be 93 billion light years in diameter. In various multiverse hypotheses, a universe is one of many causally disconnected constituent parts of a larger multiverse, which itself comprises all of space and time and its contents; the earliest scientific models of the Universe were developed by ancient Greek and Indian philosophers and were geocentric, placing Earth at the center of the Universe. Over the centuries, more precise astronomical observations led Nicolaus Copernicus to develop the heliocentric model with the Sun at the center of the Solar System. In developing the law of universal gravitation, Isaac Newton built upon Copernicus' work as well as observations by Tycho Brahe and Johannes Kepler's laws of planetary motion. Further observational improvements led to the realization that the Sun is one of hundreds of billions of stars in the Milky Way, one of at least hundreds of billions of galaxies in the Universe.
Many of the stars in our galaxy have planets. At the largest scale galaxies are distributed uniformly and the same in all directions, meaning that the Universe has neither an edge nor a center. At smaller scales, galaxies are distributed in clusters and superclusters which form immense filaments and voids in space, creating a vast foam-like structure. Discoveries in the early 20th century have suggested that the Universe had a beginning and that space has been expanding since and is still expanding at an increasing rate; the Big Bang theory is the prevailing cosmological description of the development of the Universe. Under this theory and time emerged together 13.799±0.021 billion years ago and the energy and matter present have become less dense as the Universe expanded. After an initial accelerated expansion called the inflationary epoch at around 10−32 seconds, the separation of the four known fundamental forces, the Universe cooled and continued to expand, allowing the first subatomic particles and simple atoms to form.
Dark matter gathered forming a foam-like structure of filaments and voids under the influence of gravity. Giant clouds of hydrogen and helium were drawn to the places where dark matter was most dense, forming the first galaxies and everything else seen today, it is possible to see objects that are now further away than 13.799 billion light-years because space itself has expanded, it is still expanding today. This means that objects which are now up to 46.5 billion light-years away can still be seen in their distant past, because in the past when their light was emitted, they were much closer to the Earth. From studying the movement of galaxies, it has been discovered that the universe contains much more matter than is accounted for by visible objects; this unseen matter is known as dark matter. The ΛCDM model is the most accepted model of our universe, it suggests that about 69.2%±1.2% of the mass and energy in the universe is a cosmological constant, responsible for the current expansion of space, about 25.8%±1.1% is dark matter.
Ordinary matter is therefore only 4.9% of the physical universe. Stars and visible gas clouds only form about 6% of ordinary matter, or about 0.3% of the entire universe. There are many competing hypotheses about the ultimate fate of the universe and about what, if anything, preceded the Big Bang, while other physicists and philosophers refuse to speculate, doubting that information about prior states will be accessible; some physicists have suggested various multiverse hypotheses, in which our universe might be one among many universes that exist. The physical Universe is defined as all of their contents; such contents comprise all of energy in its various forms, including electromagnetic radiation and matter, therefore planets, stars and the contents of intergalactic space. The Universe includes the physical laws that influence energy and matter, such as conservation laws, classical mechanics, relativity; the Universe is defined as "the totality of existence", or everything that exists, everything that has existed, everything that will exist.
In fact, some philosophers and scientists support the inclusion of ideas and abstract concepts – such as mathematics and logic – in the definition of the Universe. The word universe may refer to concepts such as the cosmos, the world, nature; the word universe derives from the Old French word univers, which in turn derives from the Latin word universum. The Latin word was used by Cicero and Latin authors in many of the same senses as the modern English word is used. A term for "universe" among the ancient Greek philosophers from Pythagoras onwards was τὸ πᾶν, tò pân, defined as all matter and all space, τὸ ὅλον, tò hólon, which did not include the void. Another synonym was ho kósmos. Synonyms are found in Latin authors and survive in modern languages, e.g. the German words Das All and Natur for Universe. The same synonyms are found in English, such as everything, the cosmos, the world (as in the many-worlds interpr
Metaphysics is one of the principal works of Aristotle and the first major work of the branch of philosophy with the same name. The principal subject is "being qua being," or being insofar, it examines what can be asserted about any being insofar as it is and not because of any special qualities it has. Covered are different kinds of causation and matter, the existence of mathematical objects, a prime-mover God; the Metaphysics is considered to be one of the greatest philosophical works. Its influence on the Greeks, the Muslim philosophers, the scholastic philosophers and writers such as Dante, was immense, it is a reconciliation of Plato's theory of Forms that Aristotle acquired at the Academy in Athens, with the view of the world given by common sense and the observations of the natural sciences. According to Plato, the real nature of things is unchangeable. However, the world we observe around us is and perpetually changing. Aristotle’s genius was to reconcile these two contradictory views of the world.
The result is a synthesis of the naturalism of empirical science, the rationalism of Plato, that informed the Western intellectual tradition for more than a thousand years. At the heart of the book lie three questions. What is existence, what sorts of things exist in the world? How can things continue to exist, yet undergo the change we see about us in the natural world? And how can this world be understood? By the time Aristotle was writing, the tradition of Greek philosophy was only two hundred years old, it had begun with the efforts of thinkers in the Greek world to theorize about the common structure that underlies the changes we observe in the natural world. Two contrasting theories, those of Heraclitus and Parmenides, were an important influence on both Plato and Aristotle. Heraclitus argued that things that appear to be permanent are in fact always changing. Therefore, though we believe we are surrounded by a world of things that remain identical through time, this world is in flux, with no underlying structure or identity.
By contrast, Parmenides argued that we can reach certain conclusions by means of reason alone, making no use of the senses. What we acquire through the process of reason is fixed and eternal; the world is not made up of a variety of things in constant flux, but of one single Truth or reality. Plato’s theory of forms is a synthesis of these two views. Given, any object; the form of each object we see in this world is an imperfect reflection of the perfect form of the object. For example, Plato claimed a chair may take many forms, but in the perfect world there is only one perfect form of chair. Aristotle encountered the theory of forms when he studied at the Academy, which he joined at the age of about 19 in the 360s B. C. Aristotle soon expanded on the concept of forms in his Metaphysics, he believed that in every change there is something which persists through the change, something else which did not exist before, but comes into existence as a result of the change. To explain how Socrates comes to be born Aristotle says that it is ‘matter’ that underlies the change.
The matter has the ‘form’ of Socrates imposed on it to become Socrates himself. Thus all the things around us, all substances, are composites of two radically different things: form and matter; this doctrine is sometimes known as Hylomorphism. Subsequent to the arrangement of Aristotle's works by scholars at Alexandria in the first century CE, a number of his treatises were referred to as τὰ μετὰ τὰ φυσικά; this is the origin of the title for collection of treatises now known as Aristotle's Metaphysics. Some have interpreted the expression "τὰ μετὰ τὰ φυσικά" to imply that the subject of the work goes "beyond" that of Aristotle's Physics or that it is metatheoretical in relation to the Physics, but others believe that "τὰ μετὰ τὰ φυσικά" referred to the work's place in the canonical arrangement of Aristotle's writings, at least as old as Andronicus of Rhodes or Hermippus of Smyrna. Within the Aristotelian corpus itself, the metaphysical treatises are referred to as τὰ περὶ τῆς πρώτης φιλοσοφίας.
It is notoriously difficult to specify the date at which Aristotle wrote these treatises as a whole or individually because the Metaphysics is, in Jonathan Barnes' words, "a farrago, a hotch-potch", more because of the difficulty of dating any of Aristotle's writings. In the manuscripts, books are referred to by Greek letters; the second book was given the title "little alpha," because it appears to have nothing to do with the other books or, although this is less because of its shortness. This disrupts the correspondence of letters to numbers, as book 2 is little alpha, book 3 is beta, so on. For many scholars, it is customary to refer to the books by their letter names, thus book 1 is called Alpha. It is possible that Aristotle did not write the books in the order in which they have come down to us
Earth's rotation is the rotation of Planet Earth around its own axis. Earth rotates eastward, in prograde motion; as viewed from the north pole star Polaris, Earth turns counter clockwise. The North Pole known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where Earth's axis of rotation meets its surface; this point is distinct from Earth's North Magnetic Pole. The South Pole is the other point where Earth's axis of rotation intersects its surface, in Antarctica. Earth rotates once in about 24 hours with respect to the Sun, but once every 23 hours, 56 minutes, 4 seconds with respect to other, stars. Earth's rotation is slowing with time; this is due to the tidal effects. Atomic clocks show that a modern day is longer by about 1.7 milliseconds than a century ago increasing the rate at which UTC is adjusted by leap seconds. Analysis of historical astronomical records shows a slowing trend of about 2.3 milliseconds per century since the 8th century BCE.
Among the ancient Greeks, several of the Pythagorean school believed in the rotation of Earth rather than the apparent diurnal rotation of the heavens. The first was Philolaus, though his system was complicated, including a counter-earth rotating daily about a central fire. A more conventional picture was that supported by Hicetas and Ecphantus in the fourth century BCE who assumed that Earth rotated but did not suggest that Earth revolved about the Sun. In the third century BCE, Aristarchus of Samos suggested the Sun's central place. However, Aristotle in the fourth century BCE criticized the ideas of Philolaus as being based on theory rather than observation, he established the idea of a sphere of fixed stars. This was accepted by most of those who came after, in particular Claudius Ptolemy, who thought Earth would be devastated by gales if it rotated. In 499 CE, the Indian astronomer Aryabhata wrote that the spherical Earth rotates about its axis daily, that the apparent movement of the stars is a relative motion caused by the rotation of Earth.
He provided the following analogy: "Just as a man in a boat going in one direction sees the stationary things on the bank as moving in the opposite direction, in the same way to a man at Lanka the fixed stars appear to be going westward."In the 10th century, some Muslim astronomers accepted that Earth rotates around its axis. According to al-Biruni, Abu Sa'id al-Sijzi invented an astrolabe called al-zūraqī based on the idea believed by some of his contemporaries "that the motion we see is due to the Earth's movement and not to that of the sky." The prevalence of this view is further confirmed by a reference from the 13th century which states: "According to the geometers, the Earth is in constant circular motion, what appears to be the motion of the heavens is due to the motion of the Earth and not the stars." Treatises were written to discuss its possibility, either as refutations or expressing doubts about Ptolemy's arguments against it. At the Maragha and Samarkand observatories, Earth's rotation was discussed by Qushji.
In medieval Europe, Thomas Aquinas accepted Aristotle's view and so, did John Buridan and Nicole Oresme in the fourteenth century. Not until Nicolaus Copernicus in 1543 adopted a heliocentric world system did the contemporary understanding of Earth's rotation begin to be established. Copernicus pointed out that if the movement of Earth is violent the movement of the stars must be much more so, he pointed to examples of relative motion. For Copernicus this was the first step in establishing the simpler pattern of planets circling a central Sun. Tycho Brahe, who produced accurate observations on which Kepler based his laws, used Copernicus's work as the basis of a system assuming a stationary Earth. In 1600, William Gilbert supported Earth's rotation in his treatise on Earth's magnetism and thereby influenced many of his contemporaries; those like Gilbert who did not support or reject the motion of Earth about the Sun are called "semi-Copernicans". A century after Copernicus, Riccioli disputed the model of a rotating Earth due to the lack of then-observable eastward deflections in falling bodies.
However, the contributions of Kepler and Newton gathered support for the theory of the rotation of Earth. Earth's rotation implies that the geographical poles are flattened. In his Principia, Newton predicted this flattening would occur in the ratio of 1:230, pointed to the pendulum measurements taken by Richer in 1673 as corroboration of the change in gravity, but initial measurements of meridian lengths by Picard and Cassini at the end of the 17th century suggested the opposite. However, measurements by Maupertuis and the French Geodesic Mission in the 1730s established the oblateness of Earth, thus confirming the positions of both Newton and Copernicus. In Earth's rotating frame of reference, a moving body follows an apparent path that deviates from the one it would follow in a fixed frame of reference; because of the Coriolis effect, falling bodies veer eastward from the vertical plumb line below their point of release, projectiles veer right in the Northern Hemisphere from the direction in which they are shot.
The Coriolis effect is observable at a meteorological scale, where it is responsible for the opposite directions of cyclone rotation in th
The Ancient Greek language includes the forms of Greek used in Ancient Greece and the ancient world from around the 9th century BCE to the 6th century CE. It is roughly divided into the Archaic period, Classical period, Hellenistic period, it is succeeded by medieval Greek. Koine is regarded as a separate historical stage of its own, although in its earliest form it resembled Attic Greek and in its latest form it approaches Medieval Greek. Prior to the Koine period, Greek of the classic and earlier periods included several regional dialects. Ancient Greek was the language of Homer and of fifth-century Athenian historians and philosophers, it has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article contains information about the Epic and Classical periods of the language. Ancient Greek was a pluricentric language, divided into many dialects; the main dialect groups are Attic and Ionic, Aeolic and Doric, many of them with several subdivisions.
Some dialects are found in standardized literary forms used in literature, while others are attested only in inscriptions. There are several historical forms. Homeric Greek is a literary form of Archaic Greek used in the epic poems, the "Iliad" and "Odyssey", in poems by other authors. Homeric Greek had significant differences in grammar and pronunciation from Classical Attic and other Classical-era dialects; the origins, early form and development of the Hellenic language family are not well understood because of a lack of contemporaneous evidence. Several theories exist about what Hellenic dialect groups may have existed between the divergence of early Greek-like speech from the common Proto-Indo-European language and the Classical period, they differ in some of the detail. The only attested dialect from this period is Mycenaean Greek, but its relationship to the historical dialects and the historical circumstances of the times imply that the overall groups existed in some form. Scholars assume that major Ancient Greek period dialect groups developed not than 1120 BCE, at the time of the Dorian invasion—and that their first appearances as precise alphabetic writing began in the 8th century BCE.
The invasion would not be "Dorian" unless the invaders had some cultural relationship to the historical Dorians. The invasion is known to have displaced population to the Attic-Ionic regions, who regarded themselves as descendants of the population displaced by or contending with the Dorians; the Greeks of this period believed there were three major divisions of all Greek people—Dorians and Ionians, each with their own defining and distinctive dialects. Allowing for their oversight of Arcadian, an obscure mountain dialect, Cypriot, far from the center of Greek scholarship, this division of people and language is quite similar to the results of modern archaeological-linguistic investigation. One standard formulation for the dialects is: West vs. non-west Greek is the strongest marked and earliest division, with non-west in subsets of Ionic-Attic and Aeolic vs. Arcadocypriot, or Aeolic and Arcado-Cypriot vs. Ionic-Attic. Non-west is called East Greek. Arcadocypriot descended more from the Mycenaean Greek of the Bronze Age.
Boeotian had come under a strong Northwest Greek influence, can in some respects be considered a transitional dialect. Thessalian had come under Northwest Greek influence, though to a lesser degree. Pamphylian Greek, spoken in a small area on the southwestern coast of Anatolia and little preserved in inscriptions, may be either a fifth major dialect group, or it is Mycenaean Greek overlaid by Doric, with a non-Greek native influence. Most of the dialect sub-groups listed above had further subdivisions equivalent to a city-state and its surrounding territory, or to an island. Doric notably had several intermediate divisions as well, into Island Doric, Southern Peloponnesus Doric, Northern Peloponnesus Doric; the Lesbian dialect was Aeolic Greek. All the groups were represented by colonies beyond Greece proper as well, these colonies developed local characteristics under the influence of settlers or neighbors speaking different Greek dialects; the dialects outside the Ionic group are known from inscriptions, notable exceptions being: fragments of the works of the poet Sappho from the island of Lesbos, in Aeolian, the poems of the Boeotian poet Pindar and other lyric poets in Doric.
After the conquests of Alexander the Great in the late 4th century BCE, a new international dialect known as Koine or Common Greek developed based on Attic Greek, but with influence from other dialects. This dialect replaced most of the older dialects, although Doric dialect has survived in the Tsakonian language, spoken in the region of modern Sparta. Doric has passed down its aorist terminations into most verbs of Demotic Greek. By about the 6th century CE, the Koine had metamorphosized into Medieval Greek. Ancient Macedonian was an Indo-European language at least related to Greek, but its exact relationship is unclear because of insufficient data: a dialect of Greek; the Macedonian dialect (or l