VI. TWO PSEUDO-SCIENCES—ALCHEMY AND ASTROLOGY
VII. FROM PARACELSUS TO HARVEY
VIII. MEDICINE IN THE SIXTEENTH AND SEVENTEENTH CENTURIES
IX. PHILOSOPHER-SCIENTISTS AND NEW INSTITUTIONS OF LEARNING
X. THE SUCCESSORS OF GALILEO IN PHYSICAL SCIENCE
XI. NEWTON AND THE COMPOSITION OF LIGHT
XII. NEWTON AND THE LAW OF GRAVITATION
XIII. INSTRUMENTS OF PRECISION IN THE AGE OF NEWTON
XIV. PROGRESS IN ELECTRICITY FROM GILBERT AND VON GUERICKE TO FRANKLIN
XV. NATURAL HISTORY TO THE TIME OF LINNAEUS
CHAPTER I SCIENCE IN THE DARK AGE
CHAPTER III MEDIAEVAL SCIENCE IN THE WEST
CHAPTER IV THE NEW COSMOLOGY—COPERNICUS TO KEPLER AND GALILEO
CHAPTER VI TWO PSEUDO-SCIENCES—ALCHEMY AND ASTROLOGY
CHAPTER VII FROM PARACELSUS TO HARVEY
CHAPTER VIII MEDICINE IN THE SIXTEENTH AND SEVENTEENTH CENTURIES
CHAPTER IX PHILOSOPHER-SCIENTISTS AND NEW INSTITUTIONS OF LEARNING
CHAPTER X THE SUCCESSORS OF GALILEO IN PHYSICAL SCIENCE
CHAPTER XI NEWTON AND THE COMPOSITION OF LIGHT
CHAPTER XII NEWTON AND THE LAW OF GRAVITATION
CHAPTER XIV PROGRESS IN ELECTRICITY FROM GILBERT AND VON GUERICKE TO FRANKLIN
BOOK II. THE BEGINNINGS OF MODERN SCIENCE
The studies of the present book cover the progress of science from the close of the Roman period in the fifth century A.D. to about the middle of the eighteenth century. In tracing the course of events through so long a period, a difficulty becomes prominent which everywhere besets the historian in less degree—a difficulty due to the conflict between the strictly chronological and the topical method of treatment. We must hold as closely as possible to the actual sequence of events, since, as already pointed out, one discovery leads on to another. But, on the other hand, progressive steps are taken contemporaneously in the various fields of science, and if we were to attempt to introduce these in strict chronological order we should lose all sense of topical continuity.
Our method has been to adopt a compromise, following the course of a single science in each great epoch to a convenient stopping-point, and then turning back to bring forward the story of another science. Thus, for example, we tell the story of Copernicus and Galileo, bringing the record of cosmical and mechanical progress down to about the middle of the seventeenth century, before turning back to take up the physiological progress of the fifteenth and sixteenth centuries. Once the latter stream is entered, however, we follow it without interruption to the time of Harvey and his contemporaries in the middle of the seventeenth century, where we leave it to return to the field of mechanics as exploited by the successors of Galileo, who were also the predecessors and contemporaries of Newton.
In general, it will aid the reader to recall that, so far as possible, we hold always to the same sequences of topical treatment of contemporary events; as a rule we treat first the cosmical, then the physical, then the biological sciences. The same order of treatment will be held to in succeeding volumes.
Several of the very greatest of scientific generalizations are developed in the period covered by the present book: for example, the Copernican theory of the solar system, the true doctrine of planetary motions, the laws of motion, the theory of the circulation of the blood, and the Newtonian theory of gravitation. The labors of the investigators of the early decades of the eighteenth century, terminating with Franklin's discovery of the nature of lightning and with the Linnaean classification of plants and animals, bring us to the close of our second great epoch; or, to put it otherwise, to the threshold of the modern period.
I. SCIENCE IN THE DARK AGE
An obvious distinction between the classical and mediaeval epochs may be found in the fact that the former produced, whereas the latter failed to produce, a few great thinkers in each generation who were imbued with that scepticism which is the foundation of the investigating spirit; who thought for themselves and supplied more or less rational explanations of observed phenomena. Could we eliminate the work of some score or so of classical observers and thinkers, the classical epoch would seem as much a dark age as does the epoch that succeeded it.
But immediately we are met with the question: Why do no great original investigators appear during all these later centuries? We have already offered a part explanation in the fact that the borders of civilization, where racial mingling naturally took place, were peopled with semi-barbarians. But we must not forget that in the centres of civilization all along there were many men of powerful intellect. Indeed, it would violate the principle of historical continuity to suppose that there was any sudden change in the level of mentality of the Roman world at the close of the classical period. We must assume, then, that the direction in which the great minds turned was for some reason changed. Newton is said to have alleged that he made his discoveries by "intending" his mind in a certain direction continuously. It is probable that the same explanation may be given of almost every great scientific discovery. Anaxagoras could not have thought out the theory of the moon's phases; Aristarchus could not have found out the true mechanism of the solar system; Eratosthenes could not have developed his plan for measuring the earth, had not each of these investigators "intended" his mind persistently towards the problems in question.
Nor can we doubt that men lived in every generation of the dark age who were capable of creative thought in the field of science, bad they chosen similarly to "intend" their minds in the right direction. The difficulty was that they did not so choose. Their minds had a quite different bent.