Eureka! Read online

  Eureka!

  The Birth of Science

  Andrew Gregory

  This edition published in the UK in 2017 by

  Icon Books Ltd, Omnibus Business Centre,

  39–41 North Road, London N7 9DP

  email: [email protected]

  www.iconbooks.com

  Originally published in 2001 by Icon Books Ltd

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  Faber & Faber Ltd, Bloomsbury House,

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  ISBN: 978-178578-191-9

  Text copyright © 2001 Andrew Gregory

  Preface to this edition copyright © 2017 Andrew Gregory

  The author has asserted his moral rights

  No part of this book may be reproduced in any form, or by any means, without prior permission in writing from the publisher

  Typesetting by Born Group

  Printed and bound in the UK by Clays Ltd, St Ives plc

  Contents

  Preface to the 2017 edition

  The Creation of Science

  1 The Early Greeks and their Predecessors

  Science Must Begin with Myths

  Two Cultures

  Cosmos: an Elegant Universe

  Myths and Theories

  Natural Phenomena

  2 The First Scientific Theories

  The Fathers of Medicine

  Eleatics and Atomists: Achilles and the Tortoise

  The Pythagoreans: the Secret Magic of Numbers

  Come the Time of Proof

  Euclid

  Science and Technology

  Great Achievement Assured

  3 Men of the World

  Plato

  Teleology: the Best of all Possible Worlds

  Atomism: Let us Trace the Pattern

  No Slight or Trivial Influence

  Aristotle: The Master of Those who Know

  The Terrestrial Realm

  The Heavens

  Speculations Upon Matter

  Aristotle and Qualities

  Explanations

  Direction of Explanation: Clockwork Lives

  4 Heavenly Thoughts

  Eudoxus: Thinking Regressively

  Ptolemaic Astronomy

  The Four Seasons

  Revolutionary Thinking

  Modelling the Heavens

  5 The Origins of the Cosmos and of Life: Consider your Origins

  6 Medicine and the Life Sciences

  Galen

  Ancient Thought on Blood

  Aristotle and Biology: Biology’s Beginnings

  Embryology and Species

  Taxonomy

  7 Later Greek Science: After Aristotle

  Epicurus and Epicureanism: on the Nature of Things

  Stoics: the Active and the Passive

  Archimedes

  Eratosthenes

  Hero and his Engine

  The Origins of Alchemy and Astrology

  The Decline of Greek Science? All Good Things Must Come to an End

  The Creation of Science

  Appendices

  Map of Ancient Greece

  Glossary of Terms

  Timeline of Ancient Greek Philosopher-scientists

  Further Reading

  Acknowledgements

  I would like to thank the editors, Jon Turney and Simon Flynn, for their patience and efficiency and for their comments on the manuscript. I would also like to thank Ms. Sheelagh Doherty RGN, RSCN, RM for her support, her comments and for checking the manuscript for medical accuracy. Without their help this would have been a less interesting and less accurate book.

  Dedication

  For Sheelagh, with love

  Andrew Gregory is Professor of History and Philosophy of Science at University College London. His specialisms are in ancient and early modern science, ancient philosophy, and the relation of magic and science. He is also the author of Harvey’s Heart: The Discovery of Blood Circulation (Icon, 2001), Plato’s Philosophy of Science (2001), Ancient Greek Cosmogony (2007), The Presocratics and the Supernatural (2011), and Anaximander: A Re-Assessment (2016), all published by Bloomsbury, and Plato: Timaeus and Critias (OUP, 2008).

  Preface to the 2017 Edition

  This second edition of Eureka! The Birth of Science is largely unchanged in its overall content. My view remains the same. The ancient Greeks made a fundamental and critical contribution to the development of science. That they did so was no miracle. It did not come out of nothing, but built on important work by both the Babylonians and the Egyptians. It was not inexplicable, as many important social changes can be seen to contribute to a society and culture conducive to radical intellectual change. The introduction of democracy, a relative religious freedom and important technological innovations can all be seen as important factors in a new social soil that allowed the rapid production, discussion and adoption of new ideas. Indeed, the growth of science is perhaps best seen as like that of a tree. It has many roots and requires certain conditions to flourish. The growth may at times be a little tangled, but ultimately the branches reach up towards the light. The ancient Greeks were a key root for science and were fundamental in fostering its early growth as the roots came together to form the trunk.

  The Creation of Science

  Science has done much to shape both the world we live in and the way in which we think about that world. But what are the origins of science? What came before science, and how and why was that transformed into a new and progressive way of thinking about and investigating our world? Who were the people who effected this transformation? When and where did science begin?

  Prior to science, there was technology. People knew how to do many useful things, without understanding quite why they happened, or why natural phenomena occurred. When they attempted to explain their world, it was in terms of myths and anthropomorphic gods. So thunder, lightning, earthquakes and disease were all due to the actions of the gods, while the origins of the world and human beings were a matter of myth. These myths often involved the sexual coupling of the gods – such as those of sea and sky to create earth – since procreation was one of the few models for the production of something new that the ancients possessed. These gods were supposed to have many human fallibilities. They sometimes acted in anger, jealousy or spite, and their actions were often unpredictable to humans.

  A good example here is the daily passage of the sun across the sky. What do we see, and how do we explain it? To a pre-scientific society, the sun might well be a god driving his chariot across the heavens. Many primitive cosmologies supposed the universe to be hemispherical. There was a flat earth with a hemispherical bowl of the heavens above it. So the sun would disappear in the evening and reappear each morning, but what happened in between was a mystery – the subject of myth. Many ancient societies could accurately predict the time that the sun would rise, and at what point on the horizon. Any sort of scientific explanation of the sun or its motions, though, was beyond them.

  At some point
, a new and more critical attitude came about. People began to reject myths and explanations in terms of the gods as arbitrary and fanciful. Instead, they began to use theories for which they could gather evidence and debate the merits. They considered their world to be a natural place, in the sense that it was free from supernatural intervention, and so in need of natural explanations. Thunder and lightning were to be explained in terms of storm clouds, and not the anger of the gods. The world was now seen as a place where events happened in a regular and predictable manner, and were not dependent on the whims of the gods.

  In many ways, it is remarkable that science came about at all. Science is not a ‘natural’ activity in the sense that it comes easily or instinctively to humans. Technology, the ability to manipulate our environment to our benefit, may come relatively easily; but science, involving understanding and explaining our world, does not. Nor is science a ‘natural’ way of thinking, as we can see from the fact that the first societies were dominated by myth and anthropomorphic deities. One might also consider the prevalence of non-scientific thought in the world today. Nor is science merely applied common sense. Many of the ideas of science, even at its very outset, have been quite contrary to common sense. Nor, one must say, was science a productive activity in the sense that it would reap immediate material benefits. So why, and how, did the transition to scientific thinking occur? Who was responsible for it? These are the questions that this book will investigate.

  When and where this transformation occurred is relatively easy to pin down. The first steps towards scientific explanation were taken in ancient Greece around 600 BC. Prior to that, the Babylonians and the Egyptians had evolved advanced technologies, but had not progressed beyond mythological explanations. The Greeks drew deeply on these technologies, especially in astronomy, geometry and medicine, and began to produce the first crude theories of how the world might work in an entirely natural manner. This book will follow the Greeks on their adventure in this new type of thinking, looking at the ideas and approaches that they created, and the increasing sophistication of their theories. It will also look at the social background that allowed them to initiate and develop a radically new way of looking at the world.

  This book is not a comprehensive treatment of Greek science. That would require a work many times longer than this. Rather, it attempts to capture the essence and the spirit of the Greek achievement, and something of the excitement of the debate between the Greek thinkers. It attempts to convey what the Greeks thought their world was like, and how they went about investigating it. The Greek picture of the world is of great relevance for several reasons:

  It was formative for virtually all Western thought down to the scientific revolution of the seventeenth century, not merely in science but in philosophy and religion as well. The dominant mode of thought – and most of the alternatives to it – was a combination of Greek science, Greek philosophy and Christian theology (which in turn was deeply influenced by Greek philosophy and theology). To understand the nature of the scientific revolution, one needs to understand Greek science and its strengths and weaknesses.

  The influence of Greek ideas did not come to an end with the scientific revolution. Many of their ideas, such as atomism, are still alive and well, and many of the principles laid down by the Greeks for understanding and investigating the universe are still valid today.

  Greek science displays fascinating differences from modern science. The spirit of investigation may have remained the same, but the content of science has changed radically. The Greeks had many wonderful ideas, but some look somewhat strange to the modern eye, and some are wrong. That is no great surprise, since we are talking of the pioneers of science, and a time gap of over two millennia. What I shall try to explain is why, given the resources available to the Greeks, intelligent people would have found these ideas attractive. Often the Greeks had very good reasons for their odder beliefs.

  The project begun by the ancient Greeks is one that has deeply affected every aspect of thinking in the modern world, and every aspect of our lives. Our conception of the natural world traces its ancestry to the ancient Greeks, and our science has its roots there. This book is the story of the origins of a great quest to understand the world we live in, a quest that continues today and that still owes a great deal to its originators.

  1 The Early Greeks and their Predecessors

  Science must begin with myths, and with the criticism of myths.

  Sir Karl Popper, ‘The Philosophy of Science’, in C.A. Mace (ed.), British Philosophy in the Mid-Century (1957)

  When and where science began depends to some extent on what we think science is. Science is a more sophisticated activity than technology. With technology, one knows how to do something, or when something will occur. With science, one has a theory and an explanation of why such a thing should happen. A good example is the production of iron tools. One can mine iron ore and go through the processes of refining and forging iron without having any idea of the nature of those processes or why they work. If so, one has only technology. Or one might have a theory which allows one to explain each step of the process, and so understand what is going on. One might then be said to have science. Many ancient societies clearly had technology. Indeed, we define certain historical ages by the sort of technology that was possessed. So we have the Stone Age, Bronze Age, Iron Age etc., characterised by the technology for producing stone, bronze and iron tools. All societies have had some form of technology. We might even say that some animals have a rudimentary technology, since they use tools (e.g., birds using stones to break open snail shells). We would not say, though, that they have science. Science is a step beyond technology, requiring at least the attempt to explain and understand.

  How much of a step beyond is another matter. The more one builds into a definition of science, the later one is likely to believe that it begins. As a basic minimum, though, we are looking for the following:

  Science deals with the natural world, so we are looking for an awareness of a distinction between the natural and the supernatural, and a desire to explain using only natural factors and not, for example, the intervention of the gods.

  Science is expressed in terms of theories, so we are looking for theories about the world, as opposed to the myths or poems typical of some ancient societies.

  Science is also characterised by the use of mathematics, experiment and observation. We are looking for science as opposed to mere technology.

  It would also be helpful if our candidates as the originators of science were aware of the differences between what they were doing and what their predecessors were doing.

  All of this, and rather more, we find with the ancient Greeks but not with any previous society. We are not, of course, looking for something that is identical with modern science. Science progresses, and we can hardly expect the content of ancient theories to stand comparison with modern theories. What we are looking for is something which has enough in common with modern science, in terms of orientation of investigation and the types of explanation offered, to be recognisable as its ancestor.

  Science Must Begin with Myths

  It is impossible to doubt the technological and mathematical achievements of some societies prior to the Greeks. The Babylonians had in place a sophisticated number system and means of solving equations. A great number of clay tablets have been found in tombs in what was Mesopotamia and is now Iraq (between the Tigris and Euphrates rivers), giving us a considerable insight into the achievements of the Babylonians. They managed to construct a workable calendar, by no means a trivial feat when starting from scratch. The relation between days, lunar months and solar years is a very complex one. There is not a whole number of days in a lunar month or solar year, nor a whole number of lunar months in a solar year. The Babylonians were also very good observers of the heavens. Some of their clay tablets turned out to be detailed and accurate observations of the movements of the heavens, with astronomical predictions worked out mathematically.
The best candidate for science prior to the ancient Greeks is undoubtedly Babylonian astronomy.

  While the Babylonians were very good at observation and prediction, they never got beyond describing the heavens in terms of myths and poems. They had no theories as to the nature of the heavens, and they failed to produce any explanations of the phenomena. Their predictions worked by extrapolation from the data, rather than from a model of the heavens. For example, if an eclipse has happened in year 1, year 3, year 5 and year 7, then we might predict that an eclipse will also happen in year 9. One can make this prediction without saying anything at all about the nature of the heavens or the nature of eclipses. In fairness to the Babylonians, the mathematics they used was much more sophisticated than this, as were their predictions. But there was nothing which explained what an eclipse was, or why it should happen at a particular time. The Babylonians were concerned only with when, not why – they had a technology of astronomical prediction, but not the science of astronomy. They also had a purely mythical cosmogony (theory of the creation of the universe).

  Here is a passage from the Enuma Elisha, the Babylonian creation epic, probably composed early in the second millennium BC:

  When the upper heavens had as yet no name,

  And the lower heavens had not as yet been named,

  When only the primeval Apsu which was to beget them yet existed,

  And their mother Ti’amat, who gave birth to them all: When all was as yet mixed in the waters,

  And no dry land could be seen – not even a marsh;

  When none of the Gods had yet been brought into existence,

  Or been given names, or had their destinies fixed:

  Then were the Gods created between the begetters.

  S. Toulmin and J. Goodfield, The Fabric of the Heavens (1961), p. 42.

  With the Greeks came a new sort of society with some radically different attitudes to the world and how to explain it.