Short history of Biology from the origins to the 20th Century

Front matter

A m a

Alberto Mario Simonetta |£

Short History of Biology From the Origins to the 20th Century

Chapter I

Greek philosophy and biology before the times of Aristotle; the archaic Greekwoild s ooo os cbe ette e ee prb pu e tall Caren Coda E 7 The first schools of Greek philosophy: vinta sto wakes who chad ween eeren 8 lonic-philosophets--. 05od eter Sane eere 12 Pythagoras and the Pythagoreans «2 too estu seem ior DELE eoe Dudtt a eb fone. wk 14 Theschool-or- Pedic t EVERERETPLEPPA MC UE PE HH EE ieee ee PET 15 Other philosophers and scientists us ira EIE RERO ARE UHR S 16 ThsatOTR SES. co cache tcr Ca eto DS cin Perens Ar Med ax A AE M ad a ees d 18 The SOphists ces coiere Whe deere Res ATP HIP SLEEP: 20 Socrates and Platoni i Ves Esto Rn Fre PERLE Do OE an E EE 20 Some peneral Tamar ks. scias t plac p vaio o RU Eu Dae e E Macau 22 Early Greek tédicine nirre e hec a EORR ode Bep e EEE 22

Chapter III

Gnosis, the irrational and Hellenistic sciences and the reasons of the stasis and subsequent decadence of culture «. oue enero teo ee eet mbi 73

Chapter IV

Early high schools and their relationship with the development of sciences

and philosophy 1ooco esset xEREERIRRPIA DENM ELA oe Eee Schooling in the Roman Empire 2245s Leere e E Veo ee hie caves Barly. Medicvalitities s+ asesor a LE Fac d ER Vet dU EA! Gece eae Cad Higher education in Islamic countries «125... peer rta The birth of European universities 2.62 sed eere iet a re o erect nos

Appendix To Chapter IV

A section that may be useful in order to understand and evaluate several

important problems as late as the 18th century, and I think, even

contemparary debates: 35420064 tops sd beens a quedes tae EAE Oñ what Is SCIENCE. j. 039 oer Rares PI ee ee eee ee ees Later developments. umeiona cuba Ed obe e kae pa pat te e e Sotho, 28

Chapter VI

Medieval times from the end of the Western Roman Empire to the end

uotbsdi iun dT"

Late medieval medicine and its connection with universities and the early anatomical schóols «uve es Eee DX x Aachen ae qd E delta eo The developments of biology in the late medieval and early renaissance times

Chapter VII

Vesalius and the reformation of anatomy 1c. speltbi e ep RR X prega 153 Harvey s-predecessors x. 0455 dua ad rb pF ied abe pen EE tret 182 Ae TOSS Seve ac teo wore ee Oe Ea Coe p d al d aea tec 184 The beginning of European world colonialism and the early zoological and botanical explorations ust pss dederit athe hse Ego ined ao d alow cb pest 186 Medicinedn the XVI century: +05 aot pr apt be) aoa ee heer e ee eee 188

CHAPTER VIIT

Whe 7ti Cemtutyc onasi ea eda OC ein tani tae hee eet 191 The scientific academies 5o os Rex uoce spend Rhe dos etre bie aa 196 PUDE M m 202 The advances in physiology and anatomy during the 17th century: William Harvey: uec ie edu ev Moab elo RN GMa aea eee Mechs 213 Other advances in Anatomy «rase epic RERRIATRPUOSRE MERE EE 219 Zona AAO y es esl e ebd OP Ree d a anaa td ated ere Re pee 222 The microscope opens new worlds scam exci heed Ran er eer S ER rd 226 The debate on spontaneous generation... esee 293 Physiology in the 17th century: The debate between ‘Jatrochemists’ and ‘Jatromechanists: serangane sage aseles oes EE a8 ets Nsdauberu ErbP 238 The beginnings of Paleontology i oe okies eho Pereira gc 246 The problem of contagion 3.44.42) VeL CP Oaks E ENS RA EDI Ea Rd 248 Cane etg dematks 9 qos eR Vra ex tine E tie wea Ace Re ud NS 249

Chapter IX

Some general features of this period wists arog vows ecco yee eles eee rp 251 Linnaeus and his pupils aii. eau ai aus So bea ws Ss ea ee da eda 239 Banks and British explorations Winkie. IER HERE RRED e PERS 269 Buffon and- hissschool 14 shes HE TERR CE PER ERR Ep e 270 Büffons CO ADORALOBS, (ocean dcs Casse rea Face eee, Gt SERRA ta o ERR 4 276 Marine biology cesis docte OF b RES uote ephemera niet 279

The debate on spontaneous generation $1 04.6600 oerte em re ornare 281

CHAPTER X From the beginning of the french revolution to the publication of the

Origin. OF SPECIES. 1244 dope e Oe ELENCO RR ERE 329 Some general features of this age co ssepe kee ERO Pe ns daa 229 The ‘big three of the Muséum sc, dade er LE herd and COQUE d are 333 Thé Vestibes-of Creation is 54. pe aet e US ebur Bae REA UA 356 The development of microscopes «425 cv Ree echec E bh veal 357 Anatomy and Embryology x eser itn ee cce ad EI FE SE S s 358 Mictobigloey. iav Eebraro Ee VERRE EPPHESUF ee ee Riese ss Bee AE 369 Reproduction: narena eadein sare deen einen aep mec bacs hearse 370 Physiology sertis o toca PL Cp PUDE SICUT Sedo d a ds 371 Descriptive zoology Sacco eve whew e N T S abun V os ud Yit 374 Development and the discovery of life cycles... o...n 2 eee 376 Descriptive botany: asegura sve Chea aedis Sa e Ree Ea eer d 379 Palaeontology and geology is: woh acta teet ook tcI OL Ee 384

Chapter XI

General features OF the age Bis eed ep Vp FE MERE PUE ER Es 389 Evolutionary ideas before Darwin « qus es teu ees Cue EY Vcn 391 Gharles Darwin C" 392

Preface

During the last three centuries Natural Sciences have become, crucial to the development of civilisation, and their impact on our lives is daily growing. However, in spite of the equally increasing concern for environmental issues, endangered animals and plants, not to speak of medical issues (as indeed these are marginal to this book), and of the proliferation of books on the various aspects of biology, the story of the development of biological sciences has been by and large ignored.

Apart from such treatment of the history of Biology and of the biographical informations that may be found in the general histories of Sciences and in the general biographical dictionaries of scientists, whereas there are good books on the history of Physics, Mathematics and Cosmology, and though there are many books (admittedly mostly bad) on Alchemy as the forerunner of modern Chemistry, the books, such as Nordeskjéld’s, as were written on the story of biological thought, have been long out of print and the history of biology has been confined to, at most, a brief introductory chapter in general textbooks on biological sciences, and they are often poor summaries of a type of traditional lore, which the reader may well ignore as it is nowhere apparent why their content may be relevant for the modern scholar.

Indeed a few excellent books have been published during the last 20 years or so, on the development of some topics of biological thought, such as Mayr's book “A history of biological thought", which however, is almost entirely concerned with the growth of evolutionary ideas, Stevens book “The development of biological systematics” (1994), dealing with the development of botanical systematics, or in Italy Barsanti's La scala, la mappa, l'albero (1992) on the evolution of classifications between 1600 and the middle 1800s and their connections with graphic conventions, or Omodeos (1984, 2000, 2001) and a few others, yet there a there is no comprehensive work currently available in English, and even the French transaltion of de Wit (1994) is practically unobtainable, so that, to my knowledge, the only text pratically available is Duris and Gohan's Histoire des sciences de la vie (1997).

Such a dearth of information has been the main reason which prompted me to prepare this summary, but, by itself, it may not have been sufficient reason for this work. Indeed one may legitimately ask why the knowledge of long obsolete ideas may be relevant for the modern scholar or for the cultivated layman. I do not know if my argument for it may sound convincing, but here it is.

The reader who will have the patience to go through the following chapters, will notice that the development of biological sciences was notably continuous: there were, indeed momentous periods of acceleration, periods of stasis and even, because of lack of facilities in communication of scholarly ideas and of technical problems, even periods of widespread cultural regress, but even such momentous episodes as the publication of Vesalius “Fabrica”, of Harvey’s “Exercitatio” or of Darwin’s “Origin of Species" were the culmination of periods of preparation and maturation of the scientific environment, that, without detracting from the greatness of these scholars, made their ideas readily acceptable within the scientific media. Nor do recent developments in biology escape this pattern, for good and bad, as we shall easily point out how important aspects of present scientific debates have a neat pedigree of Augustinian or even Platonic or Aristotelian origin.

Just as in any other aspect of cultural or practical life, we live (and are adapted to live) in an environment that has been forged by past events, so that, to the student of biology, the history of this branch of sciences should be as significant as the knowledge of his country’s history to the citizen of any state.

Again, we might be asked why the history of biology offered here to the reader is a history of Western biology, with just a brief chapter of the Medieval development of medicine and biology in the Muslim world. As a matter of fact, while every culture has organised the body of its biological knowledge within the framework of comprehensive theories, the non-European cultures had theories which were wiped away by the impact of Western biology. They had sound practices, excellent remedies, and both of these are increasingly received currently all over the world, but their theoretical framework was at such variance with our Western methods of scientific research and philosophical thinking that they had no impact whatsoever on the development of our ideas and are, for us Westerners, just erudite curiosities. However, the reader has, at least, to be cautioned: a good deal of the past scientific thinking of the non- European peoples is still poorly studied and even unavailable for the Western scholar. Such translations as actually exist are the work of philologists and thus often unreliable as far as the interpretation of technical terms is concerned. Much work is still needed on the history of non-Western sciences before they may be fairly assessed. The overwhelming triumph of our sciences may well have obliterated deserving discoveries; let us hope that Oriental, Amerindian and African biologists will investigate their own scientific traditions with sound methods and unbiased attitudes.

However, whether or not future research will change our outlook, there is no doubt that in the present world, the history of biology that matters to the scientist is that of Western biology.

Within the practical limits set by the size of this book, I have endeavoured to frame my account of the development of biological sciences within the general historical, social and cultural environment which surrounded both researchers and teachers. After all no one, least of all the scientists, live and work insulated from society and, as my past experience has taught me that young people are very adept to forget the history learned in high school, thence I have prefaced each chapter with a selection of dated historical references in the hope that these may help the reader to place both the personalities of the scholars and their discoveries.

This volume is not a simple translation of my Italian book: “Breve storia della Biologia dalle origini all’inizio del XX secolo”: all chapters have been revised and some have been entirely re-written and I hope that all changes are improvements.

CHAPTER I The beginnings of Greek scientific thinking

SYNOPSIS OF MAIN HISTORICAL EVENTS AND OF CONTEMPORARY THINKERS

Thales of Miletus c. 620-c. 550 BC, Anaximander c. 610-c. 540 BC

612 BC Niniveh is conquered by a coalition of Medes, Babylonians and Persians.

610 BC Ciassarres of Media destroys the last Assyrian king Asur-Uballit of Harran.

585 BC war between the Medians and the Lydians, battle on the river Halys, supposed eclipse announced by Thales and peace between the Medians and Lydians. Solon dictates the new Athenian constitution.

Anaximenes c.580-520 BC; Pythagoras of Samos c. 570-c. 500 BC

561-528/27 BC Pisistratus rules Athens. Final editing of Homeric poems.

550 BC Cyrus the elder creates the Persian empire and conquers Media.

547 BC battle of Pteria and end of the Lydian kingdom, Miletus is allied with the Persians.

Heraclitus (c. 540-c. 475 BC), Parmenides (c. 520-c. 430 BC)

539 BC Cyrus conquers Babylonia and in 538 BC authorizes the reconstruction of the Temple of Jerusalem. Ezra and Nehemiah begin the collection of the Biblical texts.

530 BC Cyrus dies while campaigning against the Sacae (Scythians).

530-522 BC Cambyses king of kings; in 525 BC defeats at Pelusium the Pharaoh Psammeticus III allied with the Athenians and unites Egypt to the Persian empire; however, in the next two centuries Egypt repeatedly regains temporary independence.

522-521 BC Persian civil war, Darius I becomes king of kings.

511 BC the Crotoniates, led by the Pythagorean sect, attack and destroy Sybaris.

Alcmeon of Croton (c. 510-c. 440 BC)

510 BC Hippias is expelled from Athens by Athenian exiles supported by Spartan troops and with the political support of the Oracle of Delphi.

507 BC Athens allies herself with the Persian satrap Artaphernes against Sparta.

500/499-497 BC the Ionian towns revolt against the Persians, only Athens and Eretria send help, but only unitl 498 BC.

495 BC battle and destruction of Miletus.

491 BC the Persian ambassadors who were asking for the submission of these towns are massacred in Athens and Sparta, marking the beginning of the first Persian war.

490 BC the Athenians and Plateians defeat the Persian army led by Hippias, Datis and Artaphernes at Marathon, the Spartan army arrives a few days later.

Anaxagoras of Clazomenae (c. 500-c. 425 BC), Aeschilus (525-456 BC), Sophocles (496-406 BC), Euripides (480-406 BC), Zeno the sophist (c. 495-c. 440 BC), Protagoras (490-420 BC), Gorgias of Lentini (c. 490-c. 420 BC), Empedocles of Agrigentum (c. 480-430 BC)

481 BC beginning of the second Persian war.

480 BC at Salamis the Greeks defeat the Persian fleet, simultaneously the Syracusans defeat at Hymera the Carthaginians, allies of the Persians.

479 BC decisive victories of the Greeks on the Persians at Plathaia and Mycale.

465 BC Xerxes is killed, civil war in Persia.

467-428 BC Age of Pericles.

449/48 BC peace of Callias, the Persian empire acknowledges Greek supremacy in the Mediterranean, Delian league and pre-eminence of Athens.

Leucippus (c. 450 BC), Socrates (470-399 BC), Democritus of Abdera (c.455 BC).

431-421, 413-404 BC Peloponnesian wars.

412 BC Sparta allies herself with Persia and, supported by Persian gold, finally beats Athens, which surrenders in 404.

399 BC trial and death of Socrates.

386 BC “Peace of the King”: the Greek states submit to the arbitration of the Persian king.

Architas of Taras (a. 388-p. 360 BC), Philolaos the Pythagorean (c. 495-c. 395 BC), Plato (429- 356 BC)

359-336 BC Philip II is king of Macedonia.

338 BC battle of Chaironeia and Macedonian overlordship of Greece.

Factors which allowed for the development of speculative thought

Before we begin the actual study of the development of Greek thinking, we must first note that, to our present knowledge, this conceptual approach is the only one in antiquity to develop a precise interest in logically rigorous abstract generalisations and for an argumentative treatment of problems.

Scholars who studied the origins of philosophical speculation have often underlined the significance that — in the process — may have had both linguistic and political factors.

It is impossible here properly to discuss either of them, but we may well briefly mention some considerations.

Such scholars who maintain the significance of linguistic factors, have remarked that while other ancient languages, such as classic Hebrew, have both an extremely simple grammar and syntax, in Greek the precise meaning of names in a sentence is defined by both article and declension and that verbs are especially complex. Thus, whenever a common name is united with an article, the meaning is automatically restricted to one or a few, precisely identified, individual objects or beings, whenever no article is used the same word signifies the whole category or class of objects which may be called by that name. At the same time the niceties of verbal flection, such as the use of dual or of aorist, allow for an extreme precision of speech. Obviously this does not mean that the interpretation of a text never poses problems, especially when, as it often happens with philosophical works, they survive as isolated quotations. The significant thing is that, as a language is the work of a whole people, the Greek language testifies, as such, to a generalised interest in clear, unambiguous speech and for the possibility of abstract thought.

As far as politics are concerned, the socio-political organisation of the Greeks is characterised by a more or less early, general evolution towards democratic assemblies. Even the Homeric poems show us chiefs who have to account for their actions at popular meetings or have to argue and persuade numbers of people in order to win their support for their plans.

We do not know whether this already occurred in Mycenean times, but the arts of persuasive oratory and of clear argument were already vital in archaic Greece. This implied logical argument as a necessary tool in debates in the assembly, and this is a natural premise to an argued philosophy and science. Indeed, traditions indicate that most of the older philosophers were leading political figures in their towns: were they eminent politicians because they were natural philosophers or was it the habit of political debates that led them to debate natural truths as well?

To all this we must add a peculiarity of Greek religion: the Greeks lived in a number of entirely independent communities; this clearly favoured the development in each community of local varieties of even the most widespread myths, whereas the lack of a “sacred book” and of an organised and hierarchical clergy made it difficult to charge people with heresy. Such a charge was posed in a few instances, but, as a general rule, thinkers felt free to propose new interpretations and elaboration of traditional myths (as is amply proved by dramatists and comedians) or to propose entirely new myths. In fact when objectively considered, the so-called “scientific theories” of the early philosophers are nothing but myths, as we shall see further on.

Finally, and we shall return to this point as well, the special significance that the “impassible Gods" had in Greek religion must be minded as well. These Deities maintain the laws of the "cosmos", of men and destiny. They watch the order of the universe, can not be prayed to and to them even Zeus must bow.

Greek philosophy and biology before the times of Aristotle; the archaic Greek world

We do not know when Greek thinking began, but it undoubtedly has developed a first precise character and organisation in the Homeric poems.

We now have a precise zerminus ante quem for the final redaction of a Homeric text in the quotation of some verses in an inscription from Ischia dated 720 BC, almost 200 years before the traditional date of the collation of the texts during the rule of Peisistratus in Athens (around 550 BC), and the fact that it comes from an island off the coast of Southern Italy proves that their knowledge was widespread.

Indeed we can not be certain of how much Homer testifies to the Helladic tradition and how much it portrays the Greek world of the IX-VIII centuries BC. Most modern scholars believe that Homer did in fact know very little of the life and times of the Mycenean lords. However the Mycenean texts, though mere administrative documents as they are, show that he did indeed know something of it, and, most significant, they bear witness of a clearly Greek people. The texts of Pylos etc. are in fact written in an exceedingly archaic Greek, but nevertheless in an unquestionably Greek language. Besides administrative matters, they relate the names of many Gods, including many of the Olympians and even Dionysos, the god of knowledge alternative to that of Apollo (and that has, incidentally disposed of a time-honoured theory that, as Homer does not mention this God must have entered Greece at a comparatively late date, after the compilation of the Homeric poems).

In recent years some scholars have maintained with good arguments and on the evidence of the decoration of some Mycenean jewels, that the Myceneans must have been familiar with some theorems on the circle and on the hexagon all somewhat more advanced than those known to contemporary Babylonian mathematicians.

However it is significant that what is usually defined as philosophic-scientific thinking, only very gradually distinguishes itself from mythologic tradition (in the literal meaning of a tale or argument about Myths), the two being completely separated in but a very few thinkers before the Hellenistic times.

The first schools of Greek philosophy

Though it is usual to preface the study of the Greek contributions to the sciences by a consideration of what in the various disciplines had been achieved by Egyptians, Sumerians, Assyrians and the other peoples of the Near East, I shall not follow this habit.

From the beginning of history and long before it, all peoples, during their long history, collected a considerable amount of empirical knowledge, and even the oldest surviving texts often mention different animals and give us an account of various medical practices which require a precise knowledge of the pharmaceutical properties of different plants and minerals, of anatomical and physiological data etc. However, all this knowledge, albeit codified and, occasionally, generalised to some extent, is always devoid of any speculative content, as, vice versa, is usually the case with Greek culture. The Greeks eventually derived such information from their neighbours (it was, indeed, an established tradition that the first great Greek thinkers, such as Thales, Pythagoras, etc., had learnt much of their knowledge during their true or supposed voyages in the lands of the Barbarians). However the Greeks were able to reshape it in the guise of theoretical generalisations, which can only be considered the forerunners of proto-philosophic and scientific thinking. At all events, there is very little that can be considered as ‘biology’ in what we know of the thoughts of the Greek philosopherscientists preceding Aristotle.

First of all, it is clear that to all presocratic philosophers the distinction between the world of living organisms and that of inorganic, non-living, matter was either obscure or has definitely to be ruled out.

The obvious character which allows these philosophers to separate living from non-living things was the fact that living things are ‘self-moving’ whereas non-living objects and corpses have to be moved by something outside them. Now such a criterion was equivocal (to Thales, among others, the lodestone was a living being as it was able to move itself towards an iron object) and left an ambiguity of somewhat intermediate objects, such as eggs or seeds. On the other hand, as they could not explain the apparently spontaneous movements of inorganic bodies, such as earth, water, and especially wind, they naturally tended to attribute them to the whims of ‘personalities’, perhaps different from those responsible for such ‘rational’ movements as those of the celestial bodies. As a result we must deem that Thales’ statement “The world is full of Gods” is a perfectly rational one.

We must here stress an observation that has had a very lasting significance in the biology and physics of the Greeks: death can easily be identified with the ceasing of breathing, and winds may well look as the breath of the world, on the other hand there is no motion apparently more spontaneous than wind, and its motion moves the seas, the clouds and any other sufficiently light body.

The Greek word ‘Pneuma (xveUua) (and of pneuma' we shall have much to say) does not mean breath as the act of breathing or the blowing wind, it means ‘the breath’, independently from what is actually breathing. Thus the concept of ‘pneuma’ will slowly evolve through the centuries, but it will always remain an important concept in all biological and physical Greek theories.

In order to understand Greek science, philosophy and religion, two other concepts are significant: namely that of ‘Noús (Noot) and of ‘Nomos (NóuoC). Taken together they characterise all that is rational both in men and in the cosmos: This, in the end, was the basis of the progressive identification with Gods of many celestial bodies, who, with their unchangeable and mathematically perfect movements, tell the times of terrestrial events.

All the points raised in the previous sentences, are already implicit in Homeric poems, which are the oldest surviving documents of archaic Greek thought.

Indeed in Homer the word ‘soma’ (Zoua), body, is used only for corpses. Living beings are always described by means of their ‘composing parts’, such as legs, arms, head etc. and of their, so to say ‘active parts’: Thymos (@úuot), Nous and Psyché (Wuxn). Thymos is that something which is responsible for emotions, while Nous is what is rational and conscious. Lastly Psyché (literally ‘breath, puff’, but also ‘butterfly’) is that which makes an individual alive and, in men, their only immortal part. Thus we often find sentences of the type “he was willing to do that, but his thymos paralysed his legs". On the other side, while ‘thymos’ is shared by men and animals, ‘Nous’ is common to men and Gods. We shall see how these ideas were significant in later discussion of the “vegetative soul, the appetitive soul and the rational soul”, which had a great influence on the development of systematics, embryology etc. and that are still implicit in many extant legislations.

The fact that ‘Psyché and ‘Pneuma’ are to some extent synonyms led to a line of thought, which began with a fragment of Anaximenes written around 546 BC and which literally reads “Just as soul (psyché) is our air (pneuma) and keeps us together (but one may also translate “controls us”) by that, so air and breath keep together (or “control”) the whole world”. It then passed through stoic and neoplatonic philosophers, and had a considerable impact on the development of the ideas of the relationship between Macro- and Microcosmos and went into vitalism down into the 20th century.

Obviously the Greeks could not overlook the significance of the relationship between the ‘soma’ (material body) of living beings and non-living bodies. So we shall shortly begin to consider the evolution of concepts concerning the nature of what is ‘material’ in the world, and more properly the increasing credit of the theory of the four ‘stoicheia (singular Xvovyevov), commonly translated as ‘elements’, but more properly ‘material principles’.

According to the essentials of the theory; all objects including the bodies of living beings, are composed of matter, and in this we can identify a certain amount of dry substance, that is of ‘earth’, mixed with a certain amount of ‘water’. The breath or vital pneuma (‘air’) gives them life, and as they are moderately hot, they must contain also some ‘fire’.

In fact the theory of the four elements: earth, water, air and fire and of the four qualities, opposed two to two, heat and cold, dampness and dryness, was expounded by Empedocles, but has almost certainly much older roots. It was finally developed fully by Aristotle (and, as we shall see, while it was accepted by many, it was questioned even by Aristotle’s friend Theophrastus). Furthermore, the theory had a great importance in the whole development of sciences until modern times.

All the hypotheses advanced by ancient peoples in order to explain the origin and nature of things are myths, and it is fascinating to follow how the ancient cosmogonies of purely religious pattern (at least in the sense we currently give to these terms), such as those of Hesiod, gradually change because of the unstated growing requirement of empirical plausibility, and eventually become what we may term as scientific hypotheses or theories. The Gods, not only for what concerns the first origin of things, but as rulers of the present course of phenomena, change from somewhat whimsical players with things and men into the rational guardians of a universal Nous.

Greek religious attitude was particularly apt for this change as, even since our earliest testimonies, the Impassive Deities: Ananke, the Moirae, Dyke, Themis, who all may be subsumed under the Latin term of ‘Fatum’ (=that which must be and cannot be otherwise), must be obeyed even by Zeus.

There is no doubt that since the earliest times the Greeks were quite convinced of an ambivalence in the relationship between the individual man and the events which befell him: man may well make his choices, but this only within the limits of what has been decreed by the impassive Deities, first of these Ananke, and the Moirae, and by the ‘laws’: Themis and Nomos. A choice different from the one so expected was indeed possible, but it was the supreme offence (hybris) upon the Gods and the implacable Nemesis was there to punish it. In this context the reply of Achilles to Thetis, who is urging him to avoid his destiny leaving alone Hector and Troy, is typical: “Should I do it, I would no more be Achilles!”.

This attitude almost naturally led to the belief in the existence of immutable laws in the universe, a concept that is the very core of all scientific thinking as we conceive it. The alternative is occasionalism, which was, indeed, advocated by quite a few Christian and by many Islamic thinkers. They maintained that everything that happens is directly the doing of God, who plays with men and things as puppets and that God’s laws are not really laws, but simple sequels of events that might be changed at any time by God’s will’.