Heraclitus

Heraclitus by Johannes Moreelse. The image depicts him as "the weeping philosopher" wringing his hands over the world, and as "the obscure" dressed in dark clothing--both traditional motifs.
Born	c. 535 BCE Ephesus
Died	c. 475 BCE (aged around 60)
Era	Ancient philosophy
Region	Western Philosophy
School	Not considered to belong to any school of thought, but later subscribers to the philosophy were "Heracliteans".
Main interests	Metaphysics, Epistemology, Ethics, Politics
Notable ideas	Logos, flow
Influenced Parmenides, Plato, Aristotle, Hegel, Engels, Nietzsche, Heidegger, Whitehead, Karl Popper, Terence McKenna

Heraclitus of Ephesus (Ancient Greek: Ἡράκλειτος ὁ Ἐφέσιος—Hērákleitos ho Ephésios; c. 535 – c. 475 BCE) was a pre-Socratic Greek philosopher, a native of the Greek city Ephesus, Ionia, on the coast of Asia Minor. He was of distinguished parentage. Little is known about his early life and education, but he regarded himself as self-taught and a pioneer of wisdom. From the lonely life he led, and still more from the riddling nature of his philosophy and his contempt for humankind in general, he was called "The Obscure" and the "Weeping Philosopher".

Heraclitus is famous for his insistence on ever-present change in the universe, as stated in the famous saying, "No man ever steps in the same river twice"^[1] (see panta rhei, below). He believed in the unity of opposites, stating that "the path up and down are one and the same", all existing entities being characterized by pairs of contrary properties. His cryptic utterance that "all entities come to be in accordance with this Logos" (literally, "word", "reason", or "account") has been the subject of numerous interpretations.

Life[link]

The main source for the life of Heraclitus is Diogenes Laërtius, although some have questioned the validity of his account as "a tissue of Hellenistic anecdotes, most of them obviously fabricated on the basis of statements in the preserved fragments."^[2] Diogenes said that Heraclitus flourished in the 69th Olympiad,^[3] 504-501 BCE. All the rest of the evidence – the people Heraclitus is said to have known, or the people who were familiar with his work – confirms the floruit. His dates of birth and death are based on a life span of 60 years, the age at which Diogenes says he died,^[4] with the floruit in the middle.

Ephesus on the coast of Asia Minor, birthplace of Heraclitus

Heraclitus was born to an aristocratic family in Ephesus, present-day Efes, Turkey. His father was named either Blosôn or Herakôn.^[3] Diogenes says that he abdicated the kingship (basileia) in favor of his brother^[5] and Strabo confirms that there was a ruling family in Ephesus descended from the Ionian founder, Androclus, which still kept the title and could sit in the chief seat at the games, as well as a few other privileges.^[6] How much power the king had is another question. Ephesus had been part of the Persian Empire since 547 and was ruled by a satrap, a more distant figure, as the Great King allowed the Ionians considerable autonomy. Diogenes says that Heraclitus used to play knucklebones with the youths in the temple of Artemis and when asked to start making laws he refused saying that the constitution (politeia) was ponêra,^[7] which can mean either that it was fundamentally wrong or that he considered it toilsome.

With regard to education, Diogenes says that Heraclitus was "wondrous" (thaumasios, which, as Plato explains in the Theaetetus and elsewhere, is the beginning of philosophy) from childhood. Diogenes relates that Sotion said he was a "hearer" of Xenophanes, which contradicts Heraclitus' statement (so says Diogenes) that he had taught himself by questioning himself. Burnet states in any case that "... Xenophanes left Ionia before Herakleitos was born."^[8] Diogenes relates that as a boy Heraclitus had said he "knew nothing" but later claimed to "know everything."^[9] His statement that he "heard no one" but "questioned himself," can be placed alongside his statement that "the things that can be seen, heard and learned are what I prize the most."^[10]

Diogenes relates that Heraclitus had a poor opinion of human affairs.^[3] He believed that Hesiod and Pythagoras lacked understanding though learned^[11] and that Homer and Archilochus deserved to be beaten.^[12] Laws needed to be defended as though they were city walls.^[13] Timon is said to have called him a "mob-reviler." Heraclitus hated the Athenians and his fellow Ephesians, wishing the latter wealth in punishment for their wicked ways.^[14] Says Diogenes: "Finally, he became a hater of his kind (misanthrope) and wandered the mountains ... making his diet of grass and herbs."

Heraclitus' life as a philosopher was interrupted by dropsy. The physicians he consulted were unable to prescribe a cure. He treated himself with a liniment of cow manure and baking in the sun, believing that this method would remove the fluid. After a day of treatment he died and was interred in the marketplace.^[15]

Works[link]

Diogenes states that Heraclitus' work was "a continuous treatise On Nature, but was divided into three discourses, one on the universe, another on politics, and a third on theology." Theophrastus says (in Diogenes) "...some parts of his work are half-finished, while other parts make a strange medley."^[5]

Diogenes also tells us that Heraclitus deposited his book as a dedication in the great temple of Artemis, the Artemisium, one of the largest temples of the 6th century BCE and one of the Seven Wonders of the Ancient World. Ancient temples were regularly used for storing treasures, and were open to private individuals under exceptional circumstances; furthermore, many subsequent philosophers in this period refer to the work. Says Kahn:^[2] "Down to the time of Plutarch and Clement, if not later, the little book of Heraclitus was available in its original form to any reader who chose to seek it out." Diogenes says:^[5] "the book acquired such fame that it produced partisans of his philosophy who were called Heracliteans."

As with other pre-Socratics, his writings only survive in fragments quoted by other authors.

Heraclitus (figured by Michelangelo) sits apart from the other philosophers in Raphael's School of Athens

Ancient characterizations[link]

The obscure[link]

At some time in antiquity he acquired this epithet denoting that his major sayings were difficult to understand. Timon of Phlius calls him "the riddler" (ainiktēs) according to Diogenes Laërtius,^[5] who had just explained that Heraclitus wrote his book "rather unclearly" (asaphesteron) so that only the "capable" should attempt it. By the time of Cicero he had become "the dark" (Ancient Greek ὁ Σκοτεινός — ho Skoteinós)^[16] because he had spoken nimis obscurē, "too obscurely", concerning nature and had done so deliberately in order to be misunderstood. The customary English translation of ὁ Σκοτεινός follows the Latin, "the obscure."

The weeping philosopher[link]

Diogenes Laërtius ascribes to Theophrastus the theory that Heraclitus did not complete some of his works because of melancholia.^[5] Later he was referred to as the "weeping philosopher," as opposed to Democritus, who is known as the "laughing philosopher."^[17] If Stobaeus^[18] writes correctly, Sotion in the early 1st century CE was already combining the two in the imaginative duo of weeping and laughing philosophers: "Among the wise, instead of anger, Heraclitus was overtaken by tears, Democritus by laughter." The view is expressed by the satirist Juvenal:^[19]

The first of prayers, best known at all the temples, is mostly for riches... Seeing this then do you not commend the one sage Democritus for laughing... and the master of the other school Heraclitus for his tears?

The motif was also adopted by Lucian of Samosata in his "Sale of Creeds," in which the duo is sold together as a complementary product in the satirical auction of philosophers. Subsequently they were considered an indispensable feature of philosophic landscapes. Montaigne proposed two archetypical views of human affairs based on them, selecting Democritus' for himself.^[20] The weeping philosopher makes an appearance in William Shakespeare's The Merchant of Venice.^[21] Donato Bramante painted a fresco, "Democritus and Heraclitus," in Casa Panigarola in Milan.^[22]

Philosophy[link]

[edit] Logos

Bust of Heraclitus at the Villa of the Papyri

"The idea that all things come to pass in accordance with this Logos"^[23] and "the Logos is common,"^[24] is expressed in two famous but obscure fragments:

This Logos holds always but humans always prove unable to understand it, both before hearing it and when they have first heard it. For though all things come to be in accordance with this Logos, humans are like the inexperienced when they experience such words and deeds as I set out, distinguishing each in accordance with its nature and saying how it is. But other people fail to notice what they do when awake, just as they forget what they do while asleep. (DK 22B1)

For this reason it is necessary to follow what is common. But although the Logos is common, most people live as if they had their own private understanding. (DK 22B2)

The meaning of Logos also is subject to interpretation: "word", "account", "plan", "formula", "measure", "proportion", "reckoning."^[25] Though Heraclitus "quite deliberately plays on the various meanings of logos",^[26] there is no compelling reason to suppose that he used it in a special technical sense, significantly different from the way it was used in ordinary Greek of his time.^[27]

The later Stoics understood it as "the account which governs everything,"^[28] and Hippolytus, in the 3rd century AD, identified it as meaning the Christian Word of God.^[29] Compare the contemporary Chinese concept of Tao.

[edit] Panta rhei, "everything flows"

Πάντα ῥεῖ (panta rhei) "everything flows" either was not spoken by Heraclitus or did not survive as a quotation of his. This famous aphorism used to characterize Heraclitus' thought comes from Simplicius,^[30] a neoplatonist, and from Plato's Cratylus. The word rhei (cf. rheology) is the Greek word for "to stream, and to the etymology of Rhea according to Plato's Cratylus."^[31]

Heraclitus by Hendrick ter Brugghen

The philosophy of Heraclitus is summed up in his cryptic utterance:^[32]

ποταμοῖσι τοῖσιν αὐτοῖσιν ἐμϐαίνουσιν, ἕτερα καὶ ἕτερα ὕδατα ἐπιρρεῖ.
Potamoisi toisin autoisin embainousin, hetera kai hetera hudata epirrei
"Ever-newer waters flow on those who step into the same rivers ."

The quote from Heraclitus appears in Plato's Cratylus twice; in 401,d as:^[33]

τὰ ὄντα ἰέναι τε πάντα καὶ μένειν οὐδέν”
Ta onta ienai te panta kai menein ouden
"All entities move and nothing remains still"

and in 402,a^[34]

πάντα χωρεῖ καὶ οὐδὲν μένει” καὶ "δὶς ἐς τὸν αὐτὸν ποταμὸν οὐκ ἂν ἐμβαίης"
Panta chōrei kai ouden menei... kai... dis es ton auton potamon ouk an embaies
"Everything changes and nothing remains still... and... you cannot step twice into the same stream"

Instead of "flow" Plato uses chōrei, to change chōros.

The assertions of flow are coupled in many fragments with the enigmatic river image:^[35]

"Ποταμοῖς τοῖς αὐτοῖς ἐμβαίνομέν τε καὶ οὐκ ἐμβαίνομεν, εἶμέν τε καὶ οὐκ εἶμεν."
"We both step and do not step in the same rivers. We are and are not."

Compare with the Latin adages Omnia mutantur and Tempora mutantur (8 CE) and the Japanese tale Hōjōki, (1200 CE) which contains the same image of the changing river, and the central Buddhist doctrine of impermanence.

[edit] Hodos ano kato, "the way up and the way down"

In ὁδὸς ἄνω κάτω^[36] the structure anō katō is more accurately translated as a hyphenated word: "the upward-downward path." They go on simultaneously and instantaneously and result in "hidden harmony".^[37] A way is a series of transformations: the πυρὸς τροπαὶ, "turnings of fire,"^[38] first into sea, then half of sea to earth and half to rarefied air.

The transformation is a replacement of one element by another: "The death of fire is the birth of air, and the death of air is the birth of water."^[39]

This world, which is the same for all, no one of gods or men has made. But it always was and will be: an ever-living fire, with measures of it kindling, and measures going out.^[40]

This latter phraseology is further elucidated:

All things are an interchange for fire, and fire for all things, just like goods for gold and gold for goods.^[41]

Heraclitus considered fire as the most fundamental element. He believed fire gave rise to the other elements and thus to all things. He regarded the soul as being a mixture of fire and water, with fire being the noble part of the soul, and water the ignoble part. A soul should therefore aim toward becoming more full of fire and less full of water: a "dry" soul was best. According to Heraclitus, worldly pleasures made the soul "moist", and he considered mastering one's worldly desires to be a noble pursuit which purified the soul's fire.^[42] Norman Melchert interpreted Heraclitus as using "fire" metaphorically, in lieu of Logos, as the origin of all things.^[43]

[edit] Dike eris, "strife is justice"

If objects are new from moment to moment so that one can never touch the same object twice, then each object must dissolve and be generated continually momentarily and an object is a harmony between a building up and a tearing down. Heraclitus calls the oppositional processes eris, "strife", and hypothesizes that the apparently stable state, dikê, or "justice," is a harmony of it:^[44]

We must know that war (polemos) is common to all and strife is justice, and that all things come into being through strife necessarily.

As Diogenes explains:^[45]

All things come into being by conflict of opposites, and the sum of things (ta hola, "the whole") flows like a stream.

In the bow metaphor Heraclitus compares the resultant to a strung bow held in shape by an equilibrium of the string tension and spring action of the bow:^[46]

There is a harmony in the bending back (palintropos) as in the case of the bow and the lyre.

[edit] Hepesthai to koino, "follow the common"

People must "follow the common (hepesthai tō ksunō)"^[47] and not live having "their own judgement (phronēsis)". He distinguishes between human laws and divine law (tou theiou "of God").^[48]

He removes the human sense of justice from his concept of God; i.e., humanity is not the image of God: "To God all things are fair and good and just, but people hold some things wrong and some right."^[49] God's custom has wisdom but human custom does not,^[50] and yet both humans and God are childish (inexperienced): "human opinions are children's toys"^[51] and "Eternity is a child moving counters in a game; the kingly power is a child's."^[52]

Wisdom is "to know the thought by which all things are steered through all things",^[53] which must not imply that people are or can be wise. Only Zeus is wise.^[54] To some degree then Heraclitus seems to be in the mystic's position of urging people to follow God's plan without much of an idea what that may be. In fact there is a note of despair: "The fairest universe (kallistos kosmos) is but a heap of rubbish (sarma, sweepings) piled up (kechumenon, poured out) at random (eikê)."^[55]

Influence[link]

Plato[link]

In Heraclitus a perceived object is a harmony between two fundamental units of change, a waxing and a waning. He typically uses the ordinary word "to become" (gignesthai or ginesthai, root sense of being born), which led to his being characterized as the philosopher of becoming rather than of being. He recognizes the changing of objects with the flow of time.

Plato argues against Heraclitus as follows:^[56]

How can that be a real thing which is never in the same state? ... for at the moment that the observer approaches, then they become other ... so that you cannot get any further in knowing their nature or state .... but if that which knows and that which is known exist ever ... then I do not think they can resemble a process or flux ....

In Plato one experienced unit is a state, or object existing, which can be observed. The time parameter is set at "ever"; that is, the state is to be presumed present between observations. Change is to be deduced by comparing observations, but no matter how many of those you are able to make, you cannot get through the mysterious gap between them to account for the change that must be occurring there.

Stoics[link]

Stoicism was a philosophical school which flourished between the 3rd century BCE and about the 3rd century CE. It began among the Greeks and became the major philosophy of the Roman Empire before declining with the rise of Christianity in the 3rd century.

Throughout their long tenure the Stoics believed that the major tenets of their philosophy derived from the thought of Heraclitus.^[57] According to Long, "the importance of Heraclitus to later Stoics is evident most plainly in Marcus Aurelius."^[58] Explicit connections of the earliest Stoics to Heraclitus showing how they arrived at their interpretation are missing but they can be inferred from the Stoic fragments. Long concludes to "modifications of Heraclitus."^[59]

The Stoics were interested in Heraclitus' treatment of fire. In addition to seeing it as the most fundamental of the four elements and the one that is quantified and determines the quantity (logos) of the other three, he presents fire as the cosmos, which was not made by any of the gods or men, but "was and is and ever shall be ever-living fire."^[60] Fire is both a substance and a motivator of change, it is active in altering other things quantitatively and performing an activity Heraclitus describes as "the judging and convicting of all things."^[61] It is "the thunderbolt that steers the course of all things."^[62] There is no reason to interpret the judgement, which is actually "to separate" (krinein), as outside of the context of "strife is justice" (see subsection above).

The earliest surviving Stoic work, the Hymn to Zeus of Cleanthes,^[63] though not explicitly referencing Heraclitus, adopts what appears to be the Heraclitean logos modified. Zeus rules the universe with law (nomos) wielding on its behalf the "forked servant", the "fire" of the "ever-living lightning." So far nothing has been said that differs from the Zeus of Homer. But then, says Cleanthes, Zeus uses the fire to "straighten out the common logos" that travels about (phoitan, "to frequent") mixing with the greater and lesser lights (heavenly bodies). This is Heraclitus' logos, but now it is confused with the "common nomos", which Zeus uses to "make the wrong (perissa, left or odd) right (artia, right or even)" and "order (kosmein) the disordered (akosma)."^[64]

The Stoic modification of Heraclitus' idea of the Logos was also influential on Jewish philosophers such as Philo of Alexandria, who connected it to "Wisdom personified" as God's creative principle. Philo uses the term Logos throughout his treatises on Hebrew Scripture in a manner clearly influenced by the Stoics.

Church fathers[link]

Democriet (laughing) & Herakliet (crying) by Cornelis van Haarlem

The church fathers were the leaders of the early Christian Church during its first five centuries of existence, roughly contemporaneous to Stoicism under the Roman Empire. The works of dozens of writers in hundreds of pages have survived.

All of them had something to say about the Christian form of the Logos. The Catholic Church found it necessary to discriminate between the Christian logos and that of Heraclitus as part of its ideological distancing from paganism. The necessity to convert by defeating paganism was of paramount importance. Hippolytus of Rome therefore identifies Heraclitus along with the other Pre-Socratics (and Academics) as sources of heresy. Church use of the methods and conclusions of ancient philosophy as such was as yet far in the future, even though many were converted philosophers.

In Refutation of All Heresies^[65] Hippolytus says: "What the blasphemous folly is of Noetus, and that he devoted himself to the tenets of Heraclitus the Obscure, not to those of Christ." Hippolytus then goes on to present the inscrutable DK B67: "God (theos) is day and night, winter and summer, ... but he takes various shapes, just as fire, when it is mingled with spices, is named according to the savor of each." The fragment seems to support pantheism if taken literally.

Hippolytus condemns the obscurity of it. He cannot accuse Heraclitus of being a heretic so he says instead: "Did not (Heraclitus) the Obscure anticipate Noetus in framing a system ...?" The apparent pantheist deity of Heraclitus (if that is what DK B67 means) must be equal to the union of opposites and therefore must be corporeal and incorporeal, divine and not-divine, dead and alive, etc., and the Trinity can only be reached by some sort of illusory shape-shifting.^[66]

The Apologist Justin Martyr, however, took a much more positive view of him. In his First Apology, he said both Socrates and Heraclitus were Christians before Christ: "those who lived reasonably are Christians, even though they have been thought atheists; as, among the Greeks, Socrates and Heraclitus, and men like them" ^[67]

See also[link]

The following articles on other topics contain non-trivial information that relates to Heraclitus in some way.

Notes[link]

Further reading[link]

• Bakalis, Nikolaos (2005). Handbook of Greek Philosophy: From Thales to the Stoics: Analysis and Fragments. Trafford Publishing. pp. 26–45 under Heraclitus. ISBN 1-4120-4843-5. 
• Barnes, Jonathan (1982). The Presocratic Philosophers [Revised Edition]. London & New York: Routledge Taylor & Francis Group. ISBN 0-415-05079-0. 
• Botten, Mick. (2011) Herakleitos - Logos Made Manifest Fastprint Publishing. ISBN 978-1-78035-064-6 All fragments, in Greek and English, with commentary and useful appendices. View as pdf at www.Herakleitos.org.uk
• Burnet, John (2003). Early Greek Philosophy. Kessinger Publishing. ISBN 0-7661-2826-1. http://books.google.com/books?id=LQYrAAAAMAAJ&dq=Early+Greek+philosophy.  First published in 1892, this book has had dozens of editions and has been used as a textbook for decades. The first edition is downloadable from Google Books.
• Davenport, Guy (translator) (1979). Herakleitos and Diogenes. Bolinas: Grey Fox Press. ISBN 0-912516-36-4.  Complete fragments of Heraclitus in English.
• Dilcher, Roman (1995). Studies in Heraclitus. Hildesheim: Olms. ISBN 3-487-09986-1. 
• Fairbanks, Arthur (1898). The First Philosophers of Greece. New York: Scribner. http://www.archive.org/details/firstphilosopher00fairiala. 
• Graham, D. W. "Heraclitus and Parmenides". In Caston, V.; Graham, D. W. Presocratic Philosophy: Essays in Honour of Alexander Mourelatos. Aldershot: Ashgate. pp. 27–44. ISBN 0-7546-0502-7. 
• Graham, D. W. (2008). "Heraclitus: Flux, Order, and Knowledge". In Curd, P.; Graham, D. W.. The Oxford Handbook of Presocratic Philosophy. New York: Oxford University Press. pp. 169–188. ISBN 978-0-19-514687-5. 
• Guthrie, W.K.C. (1962). A History of Greek Philosophy: The Earlier Presocratics and the Pythagoreans. 1. Cambridge: Cambridge University Press. 
• Heidegger, Martin; Fink, Eugen; Seibert (translator), Charles H. (1993). Heraclitus Seminar. Evanston: Northwestern University Press. ISBN 0-8101-1067-9. . Transcript of seminar in which two German philosophers analyze and discuss Heraclitus' texts.
• Heraclitus; Haxton (translator), Brooks; Hillman (Forward), James (2001). Fragments: The Collected Wisdom of Heraclitus. New York: Viking (The Penguin Group, Penguin Putnam, Inc.). ISBN 0-670-89195-9. . Parallel Greek & English.
• Kahn, Charles H. (1979). The art and thought of Heraclitus : an edition of the fragments with translation and commentary. Cambridge: Cambridge University Press. ISBN 0-521-21883-7. 
• Kirk, G.S. (1954). Heraclitus, the Cosmic Fragments. Cambridge: Cambridge University Press. 
• Kirk, G.S.; J.E. Raven (1957). The Pre-Socratic Philosophers: A Critical History with a Selection of Texts (2nd ed.). Cambridge: Cambridge University Press. 
• Laertius, Diogenes. Lives of the Eminent Philosophers. . Life of Heraclitus, translated by Robert Drew Hicks (1925)..
• Lavine, T.Z. (1984). From Socrates to Sartre: The Philosophic Quest. New York, New York: Bantam Doubleday Dell Publishing Group, Inc. (Bantam Books). Chapter 2: Shadow and Substance; Section: Plato's Sources: The Pre-SocraticPhilosophers: Heraclitus and Parmenides. ISBN 0-553-25161-9. 
• Magnus, Magus; Fuchs (introduction), Wolfgang (2010). Heraclitean Pride. Towson: Furniture Press Books. ISBN 978-0-9826299-2-5.  Creative re-creation of Heraclitus' lost book, from the fragments.
• McKirahan, R. D. (2011). Philosophy before Socrates, An Introduction With Text and Commentary. Indianapolis: Hackett. ISBN 978-1-60384-183-2. 
• Mourelatos, Alexander, ed. (1993). The Pre-Socratics : a collection of critical essays (Rev. ed.). Princeton, NJ: Princeton University Press. ISBN 0-691-02088-4. 
• Patrick, G.T.W. (1889,2010). Heraclitus of Ephesus: The Fragments. 
• Pyle, C. M. (1997). 'Democritus and Heracleitus: An Excursus on the Cover of this Book,' Milan and Lombardy in the Renaissance. Essays in Cultural History. Rome, La Fenice. (Istituto di Filologia Moderna, Università di Parma: Testi e Studi, Nuova Serie: Studi 1.) (Fortuna of the Laughing and Weeping Philosophers topos)
• Robinson, T.M. (1987). Heraclitus: Fragments: A Text and Translation with a Commentary. Toronto: University of Toronto Press. ISBN 0-8020-6913-4. 
• Sallis, John; Maly, Kenneth, eds. (1980). Heraclitean fragments. University: University of Alabama Press. ISBN 0-8173-0027-9. 
• Schofield, Malcolm; Nussbaum, Martha Craven, eds. (1982). Language and logos : studies in ancient Greek philosophy presented to G.E.L. Owen. Cambridge: Cambridge U.P.. ISBN 0-521-23640-1. 
• Taylor, C. C. W (ed.), Routledge History of Philosophy: From the Beginning to Plato, Vol. I, pp. 80 – 117. ISBN 0-203-02721-3 Master e-book ISBN, ISBN 0-203-05752-X (Adobe eReader Format) and ISBN 0-415-06272-1 (Print Edition).
• Tarán, L. (1999). "337–378". Elenchos 20: 9–52. 
• Vlastos, G. (1955). "On Heraclitus". American Journal of Philology 76 (4): 337–378. DOI:10.2307/292270. 
• Wheelwright, Philip (1959). Heraclitus. Princeton, NJ: Princeton University Press. 
• Wright, M.R. (1985). The Presocratics: The main Fragments in Greek with Introduction, Commentary and Appendix Containing Text and Translation of Aristotle on the Presocratics. Bristol: Bristol Classical Press. ISBN 0-86292-079-5.