[In the excerpt below, Debus provides an overview of the scientific revolution of the Renaissance, emphasizing the new interest in classical texts, the broader use of vernacular languages, and the expanded roles of observation, mathematics, technology, and mysticism.]

Few events in world history have been more momentous than the Scientific Revolution. The period between the mid-fifteenth and the end of the eighteenth centuries witnessed the growing cultural and political influence of Western Europe over all other parts of the globe. The new science and technology of the West was a crucial factor in this development, a fact recognized by most scholars at the time. Thus, Francis Bacon (1561–1626) observed in the Novum organum (1620) that

"it is well to observe the force and virtue and consequences of discoveries; and these are to be seen nowhere more conspicuously than in those three which were unknown to the ancients …; namely, printing, gunpowder, and the magnet. For these three have changed the whole face and state of things throughout the world; the first in literature, the second in warfare, the third in navigation; whence have followed innumerable changes; insomuch that no empire, no sect, no star seems to have exerted greater power and influence in human affairs than these mechanical discoveries." [The Works of Francis Bacon, ed. James Spedding, Robert Leslie Eillis, and Douglas Dennon Heath (Longmans, 1870)]

For Bacon these discoveries were Western in origin and relatively recent in date. He was neither the first nor the last to make such a statement, but there were few whose works were read more avidly by those who hoped to erect a new science in the seventeenth century.

But if the importance of the Scientific Revolution is readily admitted by all, the more we study its origins, the more unsure we become of its causes. In this volume we shall be concerned primarily with the two centuries from 1450 to 1650, the first date coinciding roughly with the beginning of the new humanistic interest in the classical scientific and medical texts and the second with the years just prior to the general acceptance of the mechanistic science of Descartes (1596–1650), Galileo (1564–1642), Borelli (1608–1679), Boyle (1627–1691), and Newton (1642–1727).

These two centuries present an almost bewildering maze of interests, and only rarely will an individual be found whose scientific methodology would prove to be fully acceptable to a modern scientist. Some of the scholars, whose work contributed to our modern scientific age, found magic, alchemy, and astrology no less stimulating than the new interest in mathematical abstraction, observation, and experiment. Today we find it easy—and necessary—to separate "science" from occult interests, but many then could not. And we cannot relegate this interest in a mystical world view to a few lesser figures forgotten today except by antiquarians. The writings of Isaac Newton and Johannes Kepler (1571–1630) reveal a genuine interest in transmutation and a search for universal harmonies no less than the work of Paracelsus (1493–1541), Robert Fludd (1574–1637), or John Dee (1527–1608). For the most part it has been traditional among historians of science to view their subject by hindsight, that is, to ignore those aspects of an earlier natural philosophy that no longer have a place in our scientific world. However, if we do this we cannot hope to reach any contextual understanding of the period. It will thus be our aim to treat this period in its own terms rather than ours. As we proceed we shall find that controversies over natural magic and the truth of the macrocosm-microcosm analogy were then as important as the better-remembered debates over the acceptance of the heliocentric system or the circulation of the blood.

Renaissance Science and Education

The very words "Renaissance" and "humanism" have been employed with so many connotations that there is little hope of satisfying any two scholars with a single definition. There is no need to try to do so here. To be sure, the Renaissance did involve a kind of "rebirth" of knowledge—no less than it did a rebirth of art and literature. And it was surely the period of the development of a new science. But having granted this, it is necessary to be careful to avoid simplification. The new love of nature expressed by Petrarch (d. c. 1374) and other fourteenth-century humanists had more than one effect. We readily accept that it was instrumental in the rise of a new observational study of natural phenomena, but we also find that Petrarch and later humanists deeply distrusted the traditional scholastic emphasis on philosophy and the sciences. The rhetoric and history they preferred was a conscious reply to the more technical "Aristotelian" studies that had long been the mainstay of the medieval university. The humanists sought the moral improvement of man rather than the logic and scholastic disputations characteristic of traditional higher learning.

These shifting values were to result in a new interest in educational problems. Fourteenth- and fifteenth-century reform programs were to be directed toward elementary education rather than the universities. The humanist educator Vittorino da Feltre (1378–1446) established a new school where students were urged to excel at sports and to learn military exercises. In classrooms they studied rhetoric, music, geography, and history—and, taking their examples from the ancients, they were taught to value both moral principles and political action above the basic principles of the trivium (grammar, rhetoric, and logic) or the study of traditional philosophical and scientific subjects.

Many of the most renowned humanist scholars were to be affected by this movement in educational reform. The result may be clearly seen in the work of Erasmus (1466–1536). He thought it enough for a student to learn of nature through his normal course of study in the reading of the ancient literary authors. Mathematics was not to him of much importance for an educated man. And Juan Luis Vives (1492–1540), surely the best known of all Renaissance educators, agreed fully when he argued against the study of mathematics that it tended to "withdraw the mind from practical concerns of life" and rendered it "less fit to fuse concrete and mundane realities."

But can we then say that the universities remained the centers of scientific training? For the most part they did, but there was an ever-increasing number of scholars both in medicine and the sciences who rejected the overwhelming conservatism of many—and perhaps most—of the institutions of higher learning. Peter Ramus (1515–1572) recalled his own academic training with despair:

"After having devoted three years and six months to scholastic philosophy, according to the rules of our university: after having read, discussed, and meditated on the various treatises of the Organon (for of all the books of Aristotle those especially which treated of dialectic were read and re-read during the course of three years); even after, I say, having put in all that time, reckoning up the years completely occupied by the study of the scholastic arts, I sought to learn to what end I could, as a consequence, apply the knowledge I had acquired with so much toil and fatigue. I soon perceived that all this dialectic had not rendered me more learned in history and the knowledge of antiquity, nor more skillful in eloquence, nor a better poet, not wiser in anything. Ah, what a stupefaction, what a grief! How did I deplore the misfortune of my destiny, the barrenness of a mind that after so much labor could not gather or even perceive the fruits of that wisdom which was alleged to be found so abundantly in the dialectic of Aristotle!" [Peter Ramus and the Educational Reformation of the Sixteenth Century, Frank Pierrepont Graves, 1912]

Ramus was not alone in his frustration—and his complaints were not without grounds. Paris, for example, was acknowledged as a stronghold of Galenic medicine in the sixteenth and seventeenth centuries whereas in England both the Elizabethan statutes for Cambridge (1570) and also the Laudian code for Oxford (1636) maintained the official authority of the ancients. Nor were the early professional societies necessarily better. The London College of Physicians looked on innovation with distrust. Thus, when in 1559 Dr. John Geynes dared to suggest that Galen (129/130–199/200 A.D.) might not be infallible, the reaction was immediate and severe. The good doctor was forced to sign a recantation before being received again into the company of his colleagues.

The conservatism seen in many major universities in the sixteenth and seventeenth centuries may be partially balanced by a critical tradition that had been applied to the ancient scientific texts at Oxford and Paris in the fourteenth century. This work, associated with scholasticism, was to prove particularly beneficial to the study of the physics of motion. As a scholarly tradition it was still in evidence at Padua and other northern Italian universities in the sixteenth century. For many, however, scientific criticism was a curious kind of humanistic game in which the scholar was to be commended for having eliminated the vulgar annotations and emendations of medieval origin that marred the texts of antiquity. His goal was textual purity rather than scientific truth.

In short, the educational climate in the early Renaissance was of questionable value for the development of the sciences. University training in this period may be characterized for the most part as conservative. As for the reform of primary education accomplished in the fourteenth and fifteenth centuries, this was openly antiscientific.

Humanism and Classical Literature

Dedication to the ancients is a familiar characteristic of Renaissance humanism. The search for new classical texts was intense in the fifteenth century, and each new discovery was hailed as a major achievement. No account is better known than that of Jacopo Angelo (fl. c. 1406). His ship sank as he was returning from a voyage to Constantinople made in search of manuscripts, but he managed to save his greatest discovery, a copy of the Geography of Ptolemy hitherto unknown in the West. Not long after this, in 1417, Poggio Bracciolini (1380–1459) discovered what was later to be recognized as the only copy of Lucretius's (c. 99–55 B.C.) De rerum natura to have survived from antiquity. This was to become a major stimulus for the revived interest in atomism two centuries later. And, just nine years after the recovery of Lucretius, Guarino da Verona (1370–1460) found a manuscript of the encyclopedic treatise on medicine by the second-century author, Celsus. This work, De medicina, was to exert a great influence, an influence due perhaps less to its medical content than to its language and style. This was the only major medical work to have survived from the best period of Latin prose and it was to be mined by medical humanists who sought proper Latin terminology and phrasing.

The search for new texts—and new translations—resulted in a new awareness of the importance of Greek. To be sure, Roger Bacon (c. 1214–1294) had already underscored this need in the thirteenth century, but the situation had not materially improved a century later. At that time Petrarch had lamented his own inadequate knowledge of this language. In fact he was not alone. Few Western scholars were able to use Greek until the teacher Manuel Chrysolorus (d. 1415) arrived in Italy with the Byzantine Emperor Manuel Paleologus in 1396. But helpful though Chrysolorus was, much greater enthusiasm was stirred by another Byzantine, Gemistos Plethon, on his arrival at the Council of Florence in 1439. The Greek revival was to affect all scholarly fields in the course of the fifteenth century. In medicine the humanist Thomas Linacre (c. 1460–1524) prepared Latin translations of Proclus (410–485) and of individual works of Galen. Significant though this was, his plans—only partially fulfilled—were actually far more grandiose. He projected a Latin translation of the complete works of Galen—and, with a group of scholars, a Latin translation of the complete works of Aristotle as well. Hardly less industrious was Johannes Guinter of Andernach (1505–1574), whose translations from Galen place him in the front rank of medical humanists. As professor of medicine at Paris, Guinter became one of the most prominent teachers of the young Andreas Vesalius (1514–1564).

This quest for truth in the search for accurate manuscripts was not confined solely to the study of the ancient physicians. Georg von Peuerbach (1423–1461) recognized the need for an accurate manuscript of Ptolemy's Almagest while writing his textbook, the Theoricae novae planetarum. But Peuerbach died while he was in the process of planning a journey to Italy to accomplish this end. His pupil, Johann Müller (Regiomontanus) (1436–1476) completed his master's journey and published an Epitome of the Almagest.

But Renaissance humanism cannot simply be reduced to the recovery of a pure Aristotle, Ptolemy, or Galen. No less influential on the development of modern science—and certainly part of the same humanistic movement—was the revival of the neo-Platonic, cabalistic, and Hermetic texts of late antiquity. So important did these seem to be that Cosimo de' Medici insisted that Marsilio Ficino (1433–1499) translate the recently discovered Corpus hermeticum (c. 1460) before turning to Plato or Plotinus. These mystical and religious works—to be discussed later in more detail—seemed to justify the pursuit of natural magic, a subject of great popularity among the savants of the sixteenth and seventeenth centuries. Included in this tradition was the call for a new investigation of nature through fresh observational evidence.

Coincidentally, this search for the pure and original texts of antiquity occurred when a new means existed for disseminating this knowledge, the printing press. It is interesting that the earliest printed book from Western Europe dates from 1447, at the very beginning of our period. For the first time it became possible to produce standard texts for scholars at a moderate price. In the scientific and medical fields these incunabula were for the most part printings of the old medieval scholastic texts scorned by the humanists. Thus the first version of Ptolemy's Almagest to be printed was the old medieval translation (1515). A new Latin translation appeared next (1528)—and finally the Greek text (1538), just five years prior to the De revolutionibus orbium of Copernicus. Galen and Aristotle were to proceed through the same stages.

The Growth of the Vernacular

Latin and Greek were surely the primary keys to the world of the scholar, but the Renaissance world was also characterized by a rapid growth in the use of the vernacular languages in learned fields. This is seen most strikingly in the religious pamphlets of the Reformation, where the author had an immediate need to reach his audience. But the use of the vernacular also became increasingly important in science and medicine in the course of the sixteenth century. This may be ascribed partially to the conscious nationalistic pride seen in this period. It is a time when authors wrote openly of their love of their native land and of their own language. A second factor was the feeling on the part of many of the need for a decisive break with the past. This seems to be ever more evident after the second quarter of the sixteenth century.

Recent research indicates a rapid increase in the use of the vernacular in the medical texts of the late Middle Ages. This trend intensified in the sixteenth century when a medical pamphlet war divided the Galenists from the Paracelsian medical chemists. This debate had been brought to the university level when Paracelsus lectured on medicine at Basel in his native Swiss-German in 1527. The medical establishment attacked him in force not only for the content of his lectures, but also for his choice of language. The latter was to remain a sore point among his followers for generations to come. Thus, the English Paracelsist Thomas Moffett (1553–1604) admitted—in Latin (1584)—that

"it is true that Paracelsus spoke often in German rather than Latin, but did not Hippocrates speak Greek? And why should they not both speak their native tongues? Is this worthy of reprehension in Paracelsus and to be passed over in Hippocrates, Galen and the other Greeks who spoke in their own language?"

The situation was not appreciably different in mathematics and the physical sciences. Galileo's publications in Italian remain classics of Italian literature today and in England numerous authors presented both popular and technical subjects in Tudor English. Of special interest is John Dee, who took it on himself to compose a preface to the first English translation of the Elements of Geometry by Euclid. Here he thought it necessary to explain that such a translation would pose no threat to the universities. Rather, he argued, many common folk might well for the first time be able "to find out, and devise, new workes, straunge Engines, and Instrumentes: for sundry purposes in the Common Wealth or for private pleasure and for the better maintayninge of their owne estate." Similar apologies for the publication of scientific and medical texts in the vernacular are to be found in the other major modern languages from this period.

Observation and Experiment

Any general assessment of Renaissance science must include a discussion of a number of seeming paradoxes. A recurring theme in the sixteenth-century literature is the rejection of antiquity. But, as we have already noted, this rejection most commonly was directed at scholastic translations and commentaries. Some scholars did call for a completely new natural philosophy and medicine, but many adhered to the ancient philosophy—provided that they were assured that their texts were pure and unadulterated. There were those such as William Harvey (1578–1657), who openly praised the Aristotelian heritage. Others—and here Robert Fludd is a good example—attacked the ancients viciously while integrating many ancient concepts in their own work.

Also characteristic of the period was a growing reliance on observation and a gradual move toward our understanding of experiment as a carefully planned—and repeatable—test of theory. Older classics of observational science and method were recognized and praised by Renaissance scholars, who saw in them a model to be emulated. Thus many who rejected Aristotle's physics pointed to his work on animals as a text of major importance. Because of his use of observational evidence, Archimedes (287–212 B.C.) had great weight, whereas among medieval authors Roger Bacon, Peter Perigrinus (of Maricourt) (fl. c. 1270), and Witelo (Theodoric of Freiburg) (thirteenth century) were cited for their "experimental" studies.

Yet even though Roger Bacon and others might speak of a new use of observation as the basis for an understanding of the universe, it was far more customary to rely upon fabulous accounts related by Pliny the Elder (23–79 A.D.) or other ancient encyclopedists. Even the brilliant critique of the ancient physics of motion carried out at Oxford and Paris in the fourteenth century had been based more upon deductive reasoning and the rules of logic than upon the results of any new observational evidence.

The scientists of the sixteenth century did not immediately develop a modern understanding of the use of experiment, but there is evident in their work a more general recourse to observational evidence than existed before. Thus Bernardino Telesio (1509–1588) founded his own academy at Cosenza, which was dedicated to the study of natural philosophy. Rejecting Aristotle, whose work seemed to disagree with both Scripture and experience, he turned instead to the senses as a key to the study of nature. Of equal interest is John Dee, who numbered among his mathematical sciences Archemastrie, which "teacheth to bryng to actuall experience sensible, all worthy conclusions by all the Artes Mathematicall purposed…. And bycause it procedeth by Experiences, and searcheth forth the causes of Conclusions, them selues, in Experience, it is named of some Scientia Experimentalis. The Experimentall Science." Here the word "experimental" may best be understood as "observational." The concept of the modern controlled experiment was not part of Dee's methodology.

Mathematics and Natural Phenomena

Surely no less important than the new appreciation of observational evidence was the development of quantification and the increasing reliance on mathematics as a tool. Plato had stressed the importance of mathematics, and the revived interest in his work did influence the sciences in this area. In our period Galileo stands as the key figure in this development. Viewing mathematics as the essential guide for the interpretation of nature, he sought a new description of motion through the use of mathematical abstraction. In doing so Galileo was acutely aware that he was departing from the traditional Aristotelian search for causes.

Combined with the novel use of mathematics in natural philosophy, there were dramatic new developments within mathematics itself. The work of Tartaglia (1500–1557), Cardano (1501–1576), and Viète (1540–1603) in algebra did much to advance that subject in the sixteenth century—and tedious arithmetical calculations were greatly simplified through the invention of logarithms by Napier (1550–1617). And only slightly beyond our period comes the invention of the calculus by the independent efforts of Leibniz (1646–1716) and Newton. All these tools were quickly seized upon by contemporary scientists as aids to their work.

If one were to ask the reasons for this use of mathematics in the sixteenth century, one might arrive at a variety of answers. One would surely be the new availability of the work of Archimedes, the Greek author whose approach most closely approximated that of the new science. His texts had never been completely lost, but there is clear evidence of a new Archimedean influence in the mid-sixteenth century with a series of new editions of his work. Another factor of importance is the persistence of interest in the study of motion initiated by the fourteenth-century scholars at Oxford and Paris. There seems little doubt that Galileo was as a student the beneficiary of this tradition. A third factor was surely the Platonic, neo-Platonic, and Pythagorean revival. This influence often had a mystical flavor, but whatever its form, it was an important stimulus for many scientists of the period. And finally, one might point to the need for practical mathematics associated with the practical arts and technology.

Technology

It is rewarding to pause momentarily to examine this new interest in technology. While the extent of the relationship is open to debate, it is clear that at the very least those interested in warfare required mathematical studies in their use of cannon, and the navigator had to perform calculations to determine his position at sea. This was a period that witnessed impressive advances in instrumentation, ranging from practical astrolabes for the mariner to the massive astronomical instruments built by Tycho Brahe. The telescope, the microscope, the first effective thermometers, and a host of other tools were developed by artisans and scientists alike. Indeed, the scientists were taking an active interest in the work of the tradesmen for the first time. This may be interpreted partially as a revolt against the authority of the ancients, as most ancient and medieval studies of nature were totally divorced from processes employed by workmen. The scholastic student of the medieval university agreed with the ancients and rarely left his libraries and study halls. In the Renaissance, however, we witness a great change. There may be few descriptions of the practical arts in the books of the fifteenth century, but handbooks of mining operations began to appear from the presses as early as 1510 and similar works relating to other fields appeared shortly thereafter.

In contrast to earlier periods the scientists and physicians now acknowledged openly that the scholar would do well to learn from the common man. Paracelsus advised his readers that

not all things the physician must know are taught in the academies. Now and then he must turn to old women, to Tartars who are called gypsies, to itinerant magicians, to elderly country folk and many others who are frequently held in contempt. From them he will gather his knowledge since these people have more understanding of such things than all the high colleges.

And Galileo candidly began his epoch-making Discourses and Demonstrations Concerning Two New Sciences (1638) with the following statement:

The constant activity which you Venetians display in your famous arsenal suggests to the studious mind a large field for investigation, especially that part of the work which involves mechanics; for in this department all types of instruments and machines are constantly being constructed by many artisans, among whom there must be some who, partly by inherited experience and partly by their own observations, have become highly expert and clever in explanation. [Dialogues Concerning Two New Sciences, transi. Henry Crew and Alfonso de Salvio, 1954]

This list could be greatly amplified if we took into account the great mining treatises of Agricola (14941555) and Biringuccio (fl. c. 1540), the views of Francis Bacon on the practical purpose of science, and the stated practical goals of the early scientific societies. There is little doubt that some areas of science progressed because the contribution of artisans and scientists fostered the study of practical processes. Johann Rudolph Glauber (1604–1670) was so encouraged by the developments he had witnesses that he forecast the supremacy of Germany over all Western Europe if its rulers would only follow his plan outlined in the Prosperity of Germany. And yet, even if we grant this belated recognition of technology by the scientist, there was no appreciable feedback from the small scientific community to technology until well into the eighteenth century.

Mysticism and Science

A fourth ingredient in the formation of the new science—and a most unlikely one from our post-Newtonian vantage point—was the new Renaissance interest in a mystical approach to nature. Much of this may be attributed to the strong revival of interest in the Platonic, neo-Platonic, and Hermetic writings. It is instructive to note this influence first in mathematics and then in the widespread interest in natural magic.

From our point of view Renaissance mathematics had the effect of a double-edged sword. On the one hand, the new interest in mathematics furthered the development of a mathematical approach to nature and the internal development of geometry and algebra; on the other hand, the same interest resulted in occultist investigations of all kinds related to number mysticism. Renaissance cabalistic studies encouraged a mystical numerological investigation of the Scriptures with the hope that far-reaching truths would be found. Similarly magic squares and harmonic ratios seemed to offer insight into nature and divinity. Even in antiquity this tendency was embodied in the Pythagorean tradition prior to the time of Plato. The latter's numerological speculations in the Timaeus were to continue to affect the world of learning throughout the Middle Ages, and with the revival of the texts of late antiquity in the fifteenth century the same themes were heard once again.

It is important not to try to separate the "mystical" and the "scientific" when they are both present in the work of a single author. To do so would be to distort the intellectual climate of the period. Of course it is not difficult to point to the mathematical laws governing planetary motions formulated by Kepler or the mathematical description of motion presented by Galileo. These were basic milestones in the development of modern science. But it should not be forgotten that Kepler sought to fit the orbits of the planets within a scheme based upon the regular solids, and Galileo was never to relax his adherence to circular motion for the planets. Both authors reached conclusions that were strongly influenced by their belief in the perfection of the heavens. Today we would call the first examples "scientific," the second not. But to force our distinction upon the seventeenth century is ahistorical.

Robert Fludd offers an excellent example of an Hermetic-chemical approach to mathematics. Few would have insisted more than he that mathematics was essential for any study of the universe. But Fludd would have added that the true mathematician should lift his sights high. His aim should be to show the divine harmonies of nature through the interrelationship of circles, triangles, squares, and other figures. These would clearly indicate the connections of the great world to man. Fludd sought a new approach to nature and, like Kepler and Galileo, he hoped to use mathematics as a key, but for him quantification was something quite different than it was for the others. Fludd believed that the mathematician should use this tool to study the overall design of the universe. He should not—like Galileo—be concerned with lesser phenomena such as the motion of a falling object.

The case of mathematics is of special importance because of the significance of quantification in the rise of modern science, but the occult or mystical influence of late Hellenistic philosophy had a much deeper impact on sixteenth-century thought than this alone Implicit in neo-Platonism and the Christian traditions was the belief in a unity of nature, a unity that encompassed God and the angels at the one extreme and man and the terrestrial world at the other. Along with this was a continued belief in the truth of the macrocosmmicrocosm relationship, the belief that man was created in the image of the great world, and that real correspondences do exist between man and the macrocosm.

The general acceptance of the macrocosm and the microcosm along with the great chain of being gave credence to the acceptance of correspondences existing everywhere between the celestial and sublunary worlds. In the ancient world such beliefs seemed to give a solid basis for astrology. It seemed reasonable to assume that stars should influence mankind here on earth. In the Renaissance many agreed, astral influences did indeed affect the earth and man. The Hermetic texts added a new ingredient to this world view. Largely on their basis man was now viewed as a favored link in the great chain of being. Partaking in Divine Grace, he was something more than the passive recipient of starry influences. And, as there is a general sympathy between all parts of the universe, man may affect supernature as well as be affected by it. This concept had immediate value in medicine through the doctrine of signatures. Here it was postulated that the true physician had the power successfully to seek out in the plant and mineral kingdoms those substances that correspond with the celestial bodies, and therefore ultimately with the Creator.

All this is closely related to the basis of Renaissance natural magic. The true physician of the Paracelsus or Ficino type was at the same time a magician who conceived nature to be a vital or magic force. Such a student of nature might learn to acquire natural powers not known to others and thus astonish the populace, even though these powers were known to be God-given and available to all. Indeed, to many this seemed to be one of the most attractive aspects of magic. Thus, late in life, John Dee recalled his student days at Cambridge where he had prepared a mechanical flying scarab for a Trinity College performance of Aristophanes' Peace, "whereat was great wondering, and many vaine reportes spread abroad of the meanes how that was effected." Dee's scarab was in the tradition of Hellenistic mechanical marvels, but he was also well aware that true magic meant the observational study of the unexplained or occult forces of nature. Thus in his Natural Magick John Baptista Porta (1540–1615) had explained that magic is essentially the search for wisdom and that it seeks nothing else but the "survey of the whole course of nature." Still earlier Heinrich Cornelius Agrippa (c. 1486–1535) called this the most perfect knowledge of all, and Paracelsus equated it with nature itself and spoke of it in terms of a religious quest that would lead the seeker to a greater knowledge of his Creator.

For such men natural magic was far removed from the taint of necromancy. Rather, magic was closely associated with religion through the search for divine truths in created nature. Nevertheless, the scientist who was willing to accept the title of "magician" might well expose himself to danger. Again John Dee will serve as an example. Imprisoned early in life for his active interest in astrology, he was later to have his vast library destroyed by an angry mob. Appealing to his readers for sympathy, he asked whether they could really think him such a fool as "to forsake the light of heauenly Wisedome: and to lurke in the dungeon of the Prince of darknesse?" Despite the accusations that had been made, he held himself to be "innocent, in hand and hart: for trespacing either against the lawe of God, or Man, in any of my Studies of Exercises, Philosophicall, or Mathematicall."

In reality sixteenth-century natural magic was a new attempt to unify nature and religion. For the Hermeticists and the natural magicians the works of Aristotle were flawed by heretical concepts, and they were repeatedly to recall that church councils had condemned many of these Aristotelian errors. This being the case, why should Aristotle and Galen still be the basis of university teaching when there was another interpretation of nature through natural magic and occult philosophy—subjects whose very existence depended upon the sacred Scriptures? How could it be that any Christian should prefer the atheistic Aristotle to this new and pious doctrine? In truth, they argued, knowledge may be acquired by Divine Grace alone; either by some experience such as St. Augustine's divine illumination or else by means of experiment in which the adept might attain his end with the aid of divine revelation. The religious content of early-seventeenth-century Hermeticism is evident in the work of Thomas Tymme (d. 1620), who wrote (1612) that

the Almighty Creator of the Heavens and the Earth … hath set before our eyes two most principal books: the one of nature, the other of his written Word … The wisdom of Natures book, men commonly call Natural Philosophy which serveth to allure to the contemplation of that great incomprehensible God, that wee might glorify him in the greatness of his work. For the ruled motions of the Orbes … the connection, agreement, force, virtue, and beauty of the Elements … are so many sundry natures and creatures in the world, are so many interpreters to teach us, that God is the efficient cause of them and that he is manifested in them, and by them, as their final cause to whom also they tend.

This was written to explain why he had prepared a book devoted to nature, the generation of the elements, and other essentially scientific topics. For an author such as Tymme science and the observation of nature were a form of divine service, a true link with divinity. In a sense natural research was a quest for God. The student of Renaissance science must thus cope with more than the work of Copernicus and its consequences or the anatomical research leading to the discovery of the circulation of the blood. As for scientific method, the historian must concern himself with the new interest in mathematics and quantification all the while taking care not to divorce it from subjects as alien to modern science as the doctrine of signatures and natural magic. Indeed, our science today owes much to that search for a new synthesis of man, nature, and religion, which characterized the work of many scientists and physicians four centuries ago.

Renaissance science and medicine were deeply influenced by three figures of the sixteenth century and three others from antiquity. The first three were Nicholas Copernicus (1473–1543), Andreas Vesalius, and Philliptus Aureolus Theophrastus Bombastus von Hohenheim, called Paracelsus—the last three Archimedes, Galen, and Ptolemy. All were to register their impact on the learned world at approximately the same time. Indeed, the De revolutionibus orbium (Copernicus), humani corporis fabrica (Vesalius), and the first major translation into Latin of the works of Archimedes all appeared in 1543.

The work of Paracelsus began to affect the learned world shortly after his death in 1541 when his scattered manuscripts were collected and published extensively for the first time. It is to his work that we turn next since to a greater extent than the others, Paracelsus may be viewed as a herald of the Scientific Revolution. And yet, though his call for a new approach to nature was coupled with a venomous attack on the followers of the ancients, Paracelsus himself was typical of the Renaissance in his willingness to borrow freely from the very texts and authors he rejected in print….