BELIEFS AND PHYSICS:

SOME LESSONS FROM THE ANCIENT GREEKS

 

 

 

 

 

Robert C. Newman

Interdisciplinary Biblical ResearchInstitute

Biblical Theological Seminary

www.ibri.org

 

 

 

 

 

ABSTRACT

 

Abrief sketch of ancient Greek physics from Thales to Aristotle reveals a stronginteraction between metaphysical belief and the practice of physics.  This interaction worked in bothdirections, as metaphysical views suggested (and inhibited) questions and approachesto the physical realm, and physical observations and experiments favored ordisfav­ored various metaphysical views.  Some lessons are suggested concerning how we should viewcurrent theories in modern physics.


Howdo metaphysical beliefs and physics interact?  To formulate some answers to this question, we need to lookat actual examples.  Here weconsider some of the earliest informa­tion we have on mankind seekingsystemat­ic under­stand­ing of our physi­cal environment.  Work of this sort may have been done inprevious civiliza­tions, but the first records we have come from theGreeks, beginning with Thales of Miletus shortly after 600 BC.  We will carry our survey down toAristotle in the fourth century BC, the first to attempt a comprehensivephysics.

 

Fromour perspective at the end of the twentieth centu­ry, the physics of theseearly scientist-philosophers seems crude, rash, and often absurd.  Yet scientists only 200 years from nowmay well think the same of our physics. Let us, then, try to give each ancient thinker a sympa­thet­ic reading,seeking to under­stand what forces led to each propos­al, and howphysical observa­tion and research affected metaphysical views and viceversa. 

 

Thereare some advantages in picking examples from so long ago, in spite ofdifficulties with historical sources. These early re­searchers first proposed a number of fundamen­talproblems which have not been solved to this day.  Yet we have advanced enough to see a good deal further alongthe road than they could.  We can,perhaps, assess the fruit of their labors better than we can those of morerecent physi­cists.

 

ThePhysical Substratum

 

Howdo we explain the nature of the material world which we observe?  This question was apparently first an­sweredin physical rather than supernatural terms by Thales of Miletus, a practicalthinker reputed to have made contri­butions to law, politics, civilengineering, mathematics, and astronomy; he was even credit­ed with successfullypre­dicting an eclipse of the sun in 585 BC (Nahm, 1964, pp. 32-33;Farrington, 1949, p. 31).[1]Thales proposed that there was a single basic sub­stance behind all thediverse phenom­ena we experience.[2]  His rath­er tangible choice forthis substance was water.  Thalesnot only thought water was the substance on which the earth actually floated(Aristotle, 325BCb, 2.13 [294a]),[3]but also that it was the basis of all other mate­rials.  Aristot­le (325BCa, 1.3 [983b]) sug­gestshe made this proposal because of the obvious neces­sity of moisture forlife.  Nahm (1964, p. 33) thinksperhaps it was be­cause Thales knew that water could assume the three formsC solid, liquid and vapor. 

 

ThalesÕpreference for natural causation, Farrington (1949, pp. 29-31) sug­gests,came from obser­ving various agricultural and indus­trialtechniques.  He felt free toadvocate this openly because of the relative intellectual freedom in Melitus, acity ruled at that time by mer­chants rather than a military or priestlycaste.  Though preferring nat­uralcauses, Thales does not appear to have been an athe­ist.  Arisotle (325BCc, 1.5 [411a]) says hethought Ôthat all things are full of gods.Õ  Perhaps he realized that technological processes depend onthe natural attributes of the substanc­es they manipu­late, and thisled him to extend the idea to process­es operat­ing in nature.  The proposal turned out to be afruitful one.

 

Anaximander(fl 555 BC)[4] followedThales at Miletus, and was considered his student and successor (Theophrastus,320BCb, 476).  He also followedThalesÕ belief in a single natural universal sub­stance, but rejected hischoice, water.  Aristotle (325BCd,3.5 [204b]; see also Lloyd [1970], p. 20) suggests he did this because he couldnot see water as the source of fire, since their character­istics (cold andwet vs. hot and dry) were mutually destructive.  Anax­im­ander proposed an abstract substance unlikeanything observed, which he called apeiron, meaning something like Ôunlimited,Õ Ôboundless,Õ or Ôinfinite.Õ  This basic sub­stance contained allthe opposites, and formed such secondary substances as fire and water by separa­tion(Aristotle, 325BCd, 3.5 [204b]; Simplicius, 530ADb, 32r).  These secondary substances had theirorigin in the apeironand returned to it when they were de­stroyed.

 

Anaximenes(fl 535) was a third Milesian to investigate the basic constitution ofmatter.  He too favored a singleultimate substance, but turned to an observable material, air, for hischoice.  Perhaps he felt his predecessor'sapeiron was too farremoved from observation.[5]  Anaxi­menes explained the diverseobserved materials as various mani­festations of air.  When rarefied, air becomes fire; con­densed,it forms succes­sively wind, cloud, water, earth, and stone as the degreeof conden­sation increas­es (Hippolytus, 236AD, 1.6).

 

Thecosmologies the Milesians proposed were based on their physics.  Thales had his earth floating onwater.  Anaxi­mander formed thecold earth and fiery heavens by separation from the apeiron (Plutarch, 100ADb, 2).  Anaxime­nes floated his earth onair, and employed the wind to push his stars around (Hippolytus, 236AD, 1.6).

 

The history of Milesian views about theprimary sub­stance is chiefly remarkable for the way in which the awarenessof the problems grew from one philosopher to the next. . . .  As is usual in the history of science,their actual theories strike a later age as child­ish Cthey already appeared so to Aristotle. But the mea­sure of their achievement is the advance they made ingrasp­ing the problems.  Theyrejected supernatural causation and appreciated that naturalistic explanationscan and should be given of a wide range of phenomena:  and they took the first tentative steps towards anunderstanding of the problem of change (Lloyd, 1970, pp 22-23).

 

AMathematical Substratum

 

Adifferent approach to the question of what underlies the physical world wasproposed by Pythagoras (fl 525), or possibly by one of his followers, thePythagoreans.  Having observed thatharmo­nious sounds are produced by vibrating strings whose lengths havesimple ratios, he proposed that reality consists of num­bers (Aristotle,325BCa, 13.6 [1080b], 14.3 [1090a]). Though the Pythagoreans apparently understood this in a rather crudelyliteral sense, their suggestion led to increasing inter­est in the formrather than the substance of matter. This suggestion also proved fruit­ful for research from antiq­uityonward, turning the atten­tion of physi­cists and astronomers tonumerical mea­surement and mathemat­ical modeling.  It led to substantial advances inknowledge among the Pythagorean astrono­mers.  Unfortunately, it also produced a great deal of Ômumbo-jumboand crude number-mysticismÕ (Lloyd, 1970, p. 27).

 

Plato(428-347) was influenced by the Pythagoreans, and counted knowledge of geometrya necessity for admission to his Academy. He observed that geometric drawings are at best only a roughapproximation to the ideas that lie behind them.  For example, a true tangent meets its circle at one pointonly, but it is impossible to draw this. Plato appar­ently extrapolated this observation to reality ingeneral, coming to the conclusion that ultimate reality consists of eternal,unchanging ideas, which are only imperfectly repre­sented in the changingworld of objects observable by our senses.  True knowledge is knowledge of these eternal ideas ratherthan of unreliable sensory data. The results are described by Clagett (1963, p. 84):

 

We do not have to wait until medieval orearly modern times for the application of geometry to the investiga­tion ofnature, for it began in both physics and as­tronomy in the fourth century[BC] and matured in the Hellenistic and Greco-Roman periods.  We have already suggested the basicimportance of the Pythagorean mathe­matical point of view of nature; butwhen the mathematical view was coupled with something close to scorn of theworld of the senses, as it was in some of the Platonic dialogues, little soundphysics could arise.  Even the mostapologetic Platonist will not stand behind Plato's Timaeus as a work of high scien­tific cali­ber,although it is true that some of the ideas suggest­ed therein were notwithout their influ­ence on Aristotle and later authors.

 

Motionand Vacuum

 

Meanwhile,the question of how motion could be recon­ciled with the idea of a single,universal substance was being consid­ered by Parmenides (fl 480).  He came to the rather startlingconclusion that it couldnÕt. Parmenides believed the single universal substance to be being itself. A vacuum was thus non-being, which by definition could not exist.  Therefore all space was filled with thesingle, ultimate sub­stance which could not change without beingnon-ultimate and which had no room to move (Parmenides, 480BCb).  Rather than accept­ing thetestimony of human senses as indica­ting some­thing must be wrong withhis argument, Par­men­ides chose instead to believe that our senses arein error! (Parmenides, 480BCa). Parmen­idesÕ follower Zeno (fl 445) constructed several exceedinglyclever arguments to prove that motion did not exist.  These arguments were frequently ignored but not success­fullyrefuted until the invention of calculus some 2000 years later.

 

Onesolution to the quandary posed by Parmenides was to adopt a pluralisticworldview rather than his monistic one C that there are several basic substancesrather than only one.  In thiscase, motion could take place as the different substances slipped by or mixedwith one another, even if there was no vacuum to provide extra room to moveabout in.  Empedo­cles (fl 445)adopted this approach, pro­posing that there were four elements instead ofonly one, namely earth, water, air and fire.  All material things were a mixture of these, and change tookplace when the composi­tion of various mixtures changed.  The cause of such change Empedoclestook to be two forces, which he called Love and Strife (we would call themattraction and repulsion).  Thismodel, as devel­oped further by Plato and Aristotle, was to be the dominantview in physics through the rest of antiqui­ty until modern times (Clagett,1963, p. 84).

 

Anaxagoras(fl 445) carried the pluralistic idea to an extreme by postulating theexistence of an infinite number of different sorts of things CÔseeds,Õ or Ôgerms,Õ he called them C which are infinitely small and eter­nal.  Every exist­ing thing is a mixtureof these, so that when a human eats fruit (say), the body does not make fleshand bone out of some other substance, but it extracts the flesh and bone parti­clesfrom the food (Anaxagoras, 445BC; Aristotle, 325BCd, 1.4 [187a-b]).  AnaxagorasÕ influence does not appearto have been great, as he was going against the preferred tendency to explainthe diver­sity of phenomena by as few items as possible.  OccamÕs razor was already in use longbefore Occam was born!

 

Theresponse to Parmenides which most neatly solved the problem he raised was theatomic theory, proposed by Leu­cippus (fl 435), developed by Democritus (fl410) (Sim­pli­cius, 530ADb, 28.15; Hippolytus, 236AD, 1.10-11), andstill fur­ther by Epicurus (341-270) (A‘tius, 100AD, 1.3.18; Cic­ero,43BCa, 1.26.73).  Reali­ty,said the Atom­ists, con­sists of an eternal­ly-existing, universalsubstance, but this occurs as an infinite number of un­change­able,invisibly small particles, called ÔatomsÕ (indi­visi­ble) because theycould not be cut into smaller pieces. The atoms were sepa­rated from one another by a void or vacuum, sothat motion was possible, and in fact, contin­ual (Aristotle, 325BCd, 8.9[265b]; Cicero, 43BCb, 1.6.17).

 

UnlikeAnaxagorasÕ seeds, atoms were all of the same sub­stance, but dif­feredin size and shape.  They formed thevarious objects of our experience by collision and entangle­ment Cthe origin of a particu­lar material occur­ring when the atoms cametogether, its destruc­tion when the atoms separated.  Thus change was real and didnÕt need tobe explained away as an illusion. On the other hand, sensory characteristics themselves were due to theshapes and combi­nations of the atoms, not to real colors and tastes in theatoms.  Democritus speculatedelaborately on the nature of sensory experience, and on how suchcharacteristics as hardness and softness, lightness and heaviness, were pro­ducedin various objects (Simplicius, 530ADa, 293.33; Plu­tarch, 100ADa, 8;Theophrastus, 320BCa, 6.1.6; Theophrastus, 320BCc, 49-82).  Surpris­ingly, Democritus, too,felt ratio­nal thought was more reliable than observation (SextusEmpiricus, 200BC, 7.138). 

Theancient atomic theory never achieved dominance in antiquity like the modernatomic theory has.  It ascribed theorigin of the world to chance rather than intelligence, and it had nothingbeyond necessity to explain large-scale organization within the world(Aristotle, 325BCd, 2.4 [196a-b]; Eusebius, 340AD, 14.27.4-5).[6]

 

ThePhysics of Aristotle

 

Bythe time of Aristotle (382-322), Greek astronomy had progressed to the pointthat astronomical objects were obviously much larger and further away thanmeteorological phenomena (Lloyd, 1970, p. 110; Farrington, 1949, pp.99-100).  Heraclides of PontusÕ (fl330) proposal, that the daily movement of the sun, moon and stars was actuallydue to the earthÕs rotation, may have come too late to influence Aristotle; itdid not meet with acceptance in any case (Clagett, 1963, p. 114; Sarton, 1964,pp. 506-08; Lloyd, 1970, pp. 94-97). Without telescopes, changes in the sky were not obvious beyond the moon,so it is not surprising that Aris­totle proposed a two-realm version ofphys­ics.  (1) Above the moonwas a supralunar realm without change, where all motion was eternal andcircular, following the scheme of Eudoxus (fl 365).  (2) Below the moon was the sublunar realm of change,characterized by natural vertical motion as each of the four elements soughtits own level (Clagett, 1963, pp. 84-87; Lloyd, 1970, pp. 109-10).  Aristotle modi­fied the four-elementscheme of Empedo­cles by allowing the ele­ments to be transformed fromone into another, and by adding a fifth element, aether, from which the supralunar realm wasconstructed (Clagett, 1963, pp. 85, 87; Lloyd, 1970, pp. 108-11).

 

Aristotlealso proposed four kinds of causation: (1) a material cause (like that of theMilesians), what something was made of; (2) a formal cause (like that of thePythagore­ans and Plato), how something was structured; (3) an effi­cientcause (like that of Empedocles), what forces produced it; and (4) a finalcause, for what purpose the object was made (Farrington, 1949, pp. 123-24;Clagett, 1963, pp. 84-85; Lloyd, 1970, pp. 105-06).

 

AristotleÕsphysics and causation continued to have influ­ence through antiquity andthe medieval period until modern times, as they appeared to provide bothconsistency and believ­able explanations for the observed natural or­der(Clagett, 1963, p. 84; Lloyd, 1970, pp. 99, 122).

 

InteractionsBetween Metaphysics and Physics

 

Wemust now consider what we have learned about how meta­physical beliefs andphysics interact.

 

Howwere physical concepts used to develop and evaluate metaphys­ical beliefs?

 

Thetechniques of crafts­men may have suggested natural­istic explana­tionsfor physical phenomena to Thales and his followers.

 

Thediscovery that harmonious sounds were produced when vibrating strings hadlengths in simple ratios may have led the Pythag­oreans to postulate theidea that number is the ultimate feature of reality rather than matter.

 

Therealization that geometric drawings are at best only rough approximations tothe ideas that lie behind them apparently convinced Plato that ultimate realityconsisted of eternal ideas which are only imperfectly realized in physicalthings.

 

Reluctanceto abandon sensory evidence kept many from follow­ing Parmenides, proposinginstead various models of reality in which change and motion were real.  These includ­ed the multi-elementschemes of Empedocles and Anaxagoras, and the AtomistsÕ introduc­tion of avoid and breaking the ultimate substance into tiny pieces.

 

Astronomicalevidence that the heavenly bodies were at great distances was in partresponsible (together with EudoxusÕ scheme for reducing the heavenly motions tocir­cles) for Aristotle's dis­tinc­tion between the earthly realmof change and the change­less heavens.

 

Howwere metaphysical beliefs used to develop and evaluate physical concepts andtheories?

 

TheMilesiansÕ metaphysic of natural causation led to their sug­gesting variousnatural explanations for everyday phenome­na which Greek mythology hadascribed to Zeus, Posei­don, or one of the other gods.  It also led to speculation re­gardinga most basic substance.  Thisresulted, on the one hand, in beginning attempts to study the basis of matter;on the other, it consis­tently produced (unwarranted) optimism that thenature of the substra­tum could be easily discerned.

 

ThePythagorean metaphysic of number as the basis of nature proved very fruitful insome fields, and certainly was important in introducing mathematics as a toolto under­stand reality. However, it also led to considerable number-speculation where thesubject of investigation was not hospitable to such an approach at that time.

 

PlatoÕsview that reality was in the eternal ideas, rather than in their imperfectrepresentations in nature, led him to devalue the use of observation andexperiment on physical objects in favor of purely abstract reasoning,disconnecting theory from observa­tion.

           

ParmenidesÕview that motion was logically impossible led him to reject the contrarytestimony of the senses.

 

DemocritusÕview that reality could be completely described by atoms moving in the void ledhim to a number of striking in­sights, mixed with numerous unwarrantedspecula­tions.  His stronglyreductionistic explanations ignored the possibility of higher levels of struc­tureand of design in nature.

 

Theapparent completeness and consis­tency of Aristot­leÕs division of thecosmos into two realms with two types of physics had long-term (and largelynegative) effects on the practice of physics, which were not overcome until thelate middle ages.

 

Bythe time of Plato and Aristotle, widening class divisions in the Greekcity-states were discouraging the leisured class from involvement in hands-on,technical sorts of labor.  Thisseems to have had a negative effect on any re­search which looked practi­cal,leading to the devalua­tion of the sort of physical investi­gationswhich would later transform Western society in the centuries after the Refor­mation.

 

Howdo shared metaphysical beliefs of the physics/science commu­nity influenceits research agenda?

 

Therewere apparently no really organized phys­ics or science commu­nities atthe beginning of this era, but cer­tainly the Milesians sought purelynatural explanations of phenomena. Though this encouraged experimenta­tion and observa­tion, itmade it difficult for them to explain the occurrence of order in nature. 

 

ThePythagoreans were certainly a communi­ty, though more of a religiousfellowship than a scientific society. They concen­trat­ed on applying mathematics to their investi­gations,producing some impressive results where this was possible at the time(astronomy and acoustics), but rather fantastic number-mysticism elsewhere.

 

TheAcademy of Plato was mainly successful in its mathemati­cal work, as theemphasis on reason rather than observation tended to produce abstract, logicalconstruc­tions.  PlatoÕsproposal that the movement of astronomical objects be explained by combinationsof circular motions both helped and hindered astronomical re­search.  Plato's admission of eternal forms gavebetter explana­tions for order in nature than the merely material causationof the Milesians and Atomists.

 

AristotleÕsproposal of four types of causation (mat­ter, struc­ture, energy, andpurpose) made better sense of the observed order in nature.  Together with a restoration of thevalue of observation, this led to some effective biological research in theLyceum of his time and later. 

 

SomeLessons for Today

 

Cansuch a brief tour of ancient Greek physics teach us anything about how weshould view physics today?  Ibelieve it can.  Consider thefollowing questions in the light of our survey.

 

Givena hierarchical structure to reality, is there any reason to believe anempirically constructed Ôbottom upÕ metaphysics will be anything more thanaccidentally correct before the Ôfinal physicsÕ is discovered?

 

AncientGreek science, though showing real progress, does not seem promising for thishope.  ThalesÕ and Anaxi­menesÕproposals that water and air are the ultimate sub­stances seem espe­ciallycrude to us, but they were based on certain observa­tions.  AnaximanderÕs more sophisticated ideaof an unspecified stuff behind appearances is an improve­ment, and itsought to solve the problem of contrary attrib­utes.  Anaxi­menesÕ concept of condensa­tionand rarefaction, presum­ably based on the conversion of water into ice andsteam, also marked a step forward. Aristo­tleÕs version of EmpedoclesÕ four-element theory (earth,water, air, fire), though returning to visible material as basic, at leastprovided for one element to change into another.  In retro­spect, none of these suggestions were close towhat we know to be the case today. 

 

Eventhe ancient atomic theories, though a vast im­provement with theirinvisible units of struc­ture and space between them, were unable toexplain macro­scopic attributes except by arbitrary guesswork.  Throughout the period we see increasingsophistica­tion, coupled with the incorporation of additional evidence,which eventually was revived in modern times as a new atomic theory.  But modern investigation has found thatwhat we call atoms are composites of nucleons and electrons, and that nucleonsare probably composites of quarks. There is no way yet for us to tell if quarks, too, may not becomposite.  We do not know how deepthe hierarchy is, nor whether anything lies beneath it.

 

Howdoes ÔOccam's RazorÕ influence physics? Do we tend to jump to unwar­ranted conclusions about thecompleteness of very prelim­i­nary theories?

 

ThoughÔOccam's razorÕ is a medieval term, it describes a common human tendency toconstruct the simplest theory consis­tent with the known evidence; clearly,it is valuable as a method of procedure. But the ancient Greeks had no idea how compli­cated nature might be,and tended to think they were only one layer away from the bottom.  We can see they were mistak­en,having penetrated several more layers. But what about our theories? Are we only a layer away from the bottom of things, or do we also jumpto conclu­sions when we ascribe to them an ultimacy they may not deserve?

 

Inthe area of kinematics, is it reasonable to believe nature can be limited to thethree spatial dimensions and one time dimension of modern relativity theory?

 

Thisis certainly the simplest model consistent with our current, empirical, ÔbottomupÕ physics.  But mathemat­icshas been worked out for larger dimen­sionali­ties; some of the recent Ôgrandunification theoriesÕ incorpo­rate 11 or more dimen­sions; and certainfeatures of the occult and of the supernatu­ral in Scrip­ture point toa more complex situa­tion.  OneÕsworld­view will have an influ­ence on whether this is thought to bepossible or probable, and whether it might be worth pursu­ing as a researchstrate­gy.

 

Inthe area of dynamics, is it reasonable to believe that the four currently-knownforces are all that exist?  Thatthey may be unified into a single superforce?

 

Itis certainly reasonable to believe these things in the sense that we know of noreason why they might not be true. The discussion above, however, should make us wary of too much confi­dencehere, since two of these forces (the strong and weak interactions) were onlydiscovered in the past century, and we have generally been poor prophets ofwhat advancing technol­ogy will turn up.  The desire for unifica­tion and simpli­fication hasoften been fruitful in research, but like Pythagoreanism, has equally often ledastray.

 

Inthe area of dynamics, is it reasonable to believe that knowing the ultimateparticles and physical forces will be sufficient to explain reality withoutrecourse to special initial or boundary conditions?

 

Withoutmaking use of special revelation, we do not know the answer to thisquestion.  However, the Ôfine-tun­ingÕin our universe, currently being discussed as the Ôanthropic principle,Õsuggests that planning rather than chance is the more basic characteristic ofreality.

 

Inthe area of dynamics, it is reasonable to believe that the universe is anautomaton (like a clock) that runs by itself C whether accidental or designed Cor may it be an instrument (like a guitar) that is designed for input?

 

Again,input from special revelation is helpful here, though it is currently viewed asÔmore scientificÕ to opt for a self-con­tained, closed universe.

 

Aftersome 2500 years of doing physics from inside our universe, we still donÕt knowwhether there is an ultimate sub­stratum, and if so, what it lookslike.  We have pro­gressedenough to be sure it is not water, air, or atoms C in either the ancient or modern sense ofthe word.

 

Thereis a strange resonance in reality between mathe­matics in the human mindand the structure of nature.  Wedon't know enough to say how pervasive this structure is or how it is imposed.

 

Parmenidesand Zeno were certainly mistaken about the unreality of motion.  If it finally turns out they were rightabout our senses being totally deceived, it will still have only been a luckyguess.  The human sensory apparatusand its technological extensions have revealed an orderly world of much greatercom­plexity than any of the ancients imag­ined.

 

Thereductionism of Democritus is still with us in a suit­ably updated form,but it faces some real challenges from design in nature.  Aristotle was wrong about there beingtwo different kinds of physics for the terrestrial and astronomical realms.  He might yet prove to be right for theearthly and the heavenly.


                                                        BIBLIOGRAPHY

 

Mostof the items herein are ancient works. For some of these, such as A‘tius and Sextus Empiricus, the dates givenare very approximate.  For theother ancient works, the date given is the author's date of death or floruit. Dates before 1000 AD are marked AD or BC.

 

A‘tius.  (100AD)  Relicsof the Philosophers.

Anaxagoras.  (445BC)  Fragments.

Aristotle.  (325BCa)  Metaphysics.

Aristotle.  (325BCb)  Onthe Heavens.

Aristotle.  (325BCc)  Onthe Soul.

Aristotle.  (325BCd)  Physics.

Cicero.  (43BCa)  Onthe Nature of the Gods.

Cicero.  (43BCb)  Onthe Chief Good and Evil.

Clagett, Marshall.  (1963)  Greek Sci­ence in Antiquity. New York: Collier.

Empedocles. (445BC)  Fragments.

Eusebius.  (340AD)  Preparationfor the Gospel.

Farrington, Benjamin.  (1949)  Greek Science I: Thales to Aristotle. Harmondsworth, Middlesex: Penguin.

Hippolytus.  (236AD)  Refutationof All Heresies.

Lloyd, G. E. R.  (1970)  EarlyGreek Science: Thales to Aristotle.  New York: W. W. Norton.

Nahm, Milton C., ed.  (1964)  Selections from Early Greek Philosophy, 4th ed.  Englewood Cliffs, NJ: Prentice-Hall.

Par­meni­des.  (480BCa)  The Way of Opinion.

Parmenides.  (480BCb)  TheWay of Truth.

Plutarch.  (100ADa)  AgainstColotes.

Plutarch.  (100ADb)  Miscellanies.

Sarton, George.  (1964)  AHistory of Science: Ancient Science Through the Golden Age of Greece (New York: Wiley Science Editions.

Sextus Empiricus.  (200BC)  Against the Professors.

Simplicius.  (530ADa)  Onthe Heavens.

Simplicius.  (530ADb)  Physics.

Theophrastus.  (320BCa)  Causesof Plants.

Theophrastus.  (320BCb)  Doctrinesof Natural Philosophy.

Theo­phrastus.  (320BCc)  On Sense Percep­tion.

 



    [1]Some skepticism isrecommended about the eclipse story, given first in Herodotus Persian Wars 1.74. See Sarton(1964, pp. 170-71).

    [2]But see Lloyd (1970,pp. 18-20), who thinks Thales was speaking of the origin of different sorts ofmatter rather than their present composition.

    [3]Most of theClassical references in this paper can be found in Nahm (1964), though I havetranslated his titles into English.

  [4]Chronological dataon the various ancients comes from Lloyd (1970) or the Oxford ClassicalDictionary.

    [5]Simplicius, 530ADb,6r: Ô... he regards [the basic sub­stance] as not indeterminate butdeterminate.Õ

    [6]See also thesearching criticisms in Theophrastus (320BCc, 49-82).