The Origins of Modern Science

Herbert Butterfield, in his book The Origins of Modern Science, tells the story of the development of modern science by focusing on the ideational changes in what is now referred to as science from the late Middle Ages until the advent of the French Revolution, with primary emphasis on the development of the modern understanding of motion. This is a brilliant choice, as it was the development of a robust physical and mathematical model of motion that allowed Newton to unite terrestrial and astronomical physics into a universal set of physical laws describing mechanics.

Having come across many references to this book in scientific histories, I decided to re-read it. This book was one of the texts for a class in the History of Science I took many years ago at Oregon State University.  It has much still to recommend it.

Butterfield provides an excellent summary of the ancient Greek physical models upon which first Arab scholars, then medieval Western thinkers employed to bring some understanding of both the sublunary (terrestrial) sphere, summarized and synthesized by Aristotle, and the remaining (astronomical) spheres, summarized and synthesized by Ptolemy. The ultimate limitations of both of these models and their ultimate replacement with a unified view came from the increased emphasis on experimentation and the more extensive employment of mathematical models to explain physical phenomena. While the ancients and the Muslims used mathematics to create predictive astronomical models and practically apply them to compute calendars, they did not generally use the same analysis to physically explain the terrestrial sphere. The author also points out that exploring Nature through experimentation was not suppressed by Muslim or medieval academics, but was less prominent than it became in the burgeoning modern scientific method, particularly as promoted by Francis Bacon with his strong emphasis on empiricism.

Butterfield suggests that Galileo and Descartes both had large roles in the birth of modern science through their employment of mathematical and geometrical models to to explain and explore the physics of terrestrial as well as astronomical motion.

Galileo heavily influenced the future employment of the scientific method through not only his use of mathematical modeling, but through his use of more rigorous experimentation in validating his models. This can be illustrated by his attempts to measure time intervals more accurately. The older Greek ideas about time were murky, based on the psychological perception of time as something that was variable.  In Galileo’s early experiments with a simple gravity pendulum, he found that the period of the pendulum was consistent and essentially constant, which suggested to him that time was not variable, but regular, and from that he developed time-measuring devices from pendulums to facilitate his measurements of objects in motion.

Perhaps one of the most difficult, and thereby amazing, changes in thinking about motion came with the development of the concept of inertia.  Galileo first developed and applied the idea, extending the older and more limited idea of impetus, but did not free completely the concept of motion from the old Aristotelian physics. Galileo’s idea of inertia was defined to solve problems of orbital mechanics: he applied it only to circular motion in attempting to understand the paths of planets and moons. But he did not fully relinquish the old Aristotelian ideas of motion terrestrially.

Descartes was able to refine this idea of inertia into the more general understanding that Newton adopted, and which is truly modern:  A body in motion moves in a straight line and continues with the same momentum unless it is acted upon by some other agency or force. Descartes’ deduced this more general concept of inertia from his earlier development of the idea of the conservation of momentum, itself which was the grandfather of the various conservation laws of modern science.

However, Descartes himself was unable to extricate his thinking entirely from the Aristotelian physical model. It is from Aristotle that the phrase Nature abhors a vacuum arose, and underpins the Aristotelian idea that no action can be initiated from a distance.  Aristotle insisted that an object changes its motion only under the direct influence of another object or substance, and that space was filled, in some way or other, with material substances that allowed the direct propagation of forces that modified the motion of an object. Descartes built an elaborate deductive description of Nature based on this Aristotelian concept, historically and scientifically a blind alley.  Butterfield suggests that Descarte’s ultimate limitation was to rely too much on the powers of logical deduction, and too little on direct observation. Ironically, Descartes, as the author of the modern algebraic approach to (analytical) geometry, also used too little mathematical modeling in his attempt to reason out the behavior of objects in motion.

Newton’s grand synthesis of terrestrial and astronomical mechanics was built on his deceptively simple three Laws of Motion (1), each inherited in part from his predecessors. These laws were placed in a world alien ultimately to all who preceded him:  An absolute framework of three-dimensional space, mostly empty, with time treated as a steady and precise beat by which all events marched ever forward.  His development of the Universal Law of Gravitation completed the tie between terrestrial and astronomical physics, with all objects in the universe attracting each other in a precise way, such that the behavior of the motion of cannonballs and the motion of the planets could be described using the same rules.  Butterfield opined that  "Both Descartes and Newton were in the first rank of geometers; but the ultimate victory of Newton has a particular significance for us in that it vindicated the alliance of geometry with the experimental method against the elaborate deductive system of Descartes. The clean and comparatively empty Newtonian skies ultimately carried the day against a Cartesian universe packed with matter and agitated with whirlpools, for the existence of which scientific observation provided no evidence." (Chapter 8)  (page 170) 

There is much more on the specifics of modern scientific origins, including some discussion of the early development of biology, evolution, chemistry and optics, and additional coverage of the emergence of the Copernican heliocentric model of the solar system.

Butterfield’s treatment of history follows somewhat von Ranke’s approach; he is wary of overstating the effect of leading ideas, of too quickly employing the pithily summarized ideas as stereotypical concepts, and in particular of ignoring both the role of human proclivities and the unwieldy swirl of change that characterizes human history. (Butterfield is less convinced by von Ranke’s heavy insistence on empiricism and the goal of representing history as it actually happened.)  He points out repeatedly that the main ideas of early science were developed from many, often inextricable influences, be they societal, religious, political, academic and so on.

As Arthur Koestler pointed out in The Sleepwalkers, and as can be seen with Galileo’s and Descartes’ efforts, useful and even brilliant things were discovered or constructed within the ultimately discarded framework of the old Greek philosophical models. In another example, Kepler’s desire to extend the Ptolemaic model using the simplest geometrical models drove him to search, in vain, for a heliocentric model based on the geometry of the perfect solids, but in the process, he discovered his three Laws of Planetary Motion, which were finally absorbed into the Newtonian synthesis. No one thread of explanation suffices to explain adequately the origins of modern science. Newton’s own view of the world was a mix of the radical modern elements for which he is celebrated, and the accepted and unscientific ideas of his day: he spent more time thinking about numerology, alchemy and Christian theology than what we today label science.

Butterfield, a Christian historian, finished by saying of science that  "Our Graeco-Roman roots and our Christian heritage were so profound - so central to our thinking - that it has required centuries of pulls and pressures, and almost a conflict of civilizations in our very midst, to make clear that the center had long ago shifted. At one time the effects of the scientific revolution, and the changes contemporary with it, would be masked by the persistence of our classical traditions and education . . . At another time these effects would be concealed through that popular attachment to religion which so helped to form the character of even the 19th century in Britain . . . (Modern science) as a new factor immediately began to elbow the other ones away, pushing them back from their central position . . . the result was the emergence of a civilization . . . that could cut itself away from its Graeco-Roman heritage in general, away from Christianity itself - only too confident in its power to exist independent of anything of the kind. We know now that what was emerging towards the end of the seventeenth century was a civilization exhilaratingly new perhaps, but strange as Nineveh and Babylon. That is why, since the rise of Christianity, there is no landmark in history that is worthy to be compared with this." (Chapter 10)  (page 201) 

 

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Notes

1. Newton's Laws of Motion. Succinctly stated, they are:

1. Inertia. The velocity of a mass remains unchanged until an unbalanced force acts upon it. Or, a body in motion moves in a straight line and continues with the same momentum unless it is acted upon by some other agency or force.
2. Force. A force is an acceleration applied to a mass. Acceleration is a change in velocity, that is either or both a change in direction or speed.
3. Action and Reaction. For every action applied to a mass there is an equal and opposite re-action.