Matter, Theories of

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MATTER, THEORIES OF. Philosophical ideas about the nature and constitution of bodies saw dramatic change in the early modern period, and new thinking about matter became a major factor in the so-called scientific revolution, contributing every bit as much to the new worldview of the early modern period as the changes in cosmology following from Copernicus's attempt to reform astronomy. Like the reforms in cosmology, changes in theories of matter were not simply recondite transformations within specialist natural philosophy, but were seen to have significant implications in other important aspects of intellectual life, most notably in theology.


Even in the Middle Ages the dominant Aristotelian theory was subject to criticism and refinement. Aristotelian theory was based on a metaphysics known as hylomorphism, in which bodies were characterized as an inseparable combination of matter and form, and a physics in which all bodies were held to consist of a particular combination of the four elements: fire, air, water, earth. These ideas could hold sway in university natural philosophy curricula, but they proved inadequate as far as practitioners of alchemy were concerned. Driven chiefly by a concern to understand phenomena that became apparent in what we would call chemical reactions, alchemists developed a belief in minima naturalia, or natural minimum-sized particles of reagents. These ideas, first developed among Arab alchemists, were influentially expounded in the Summa perfectionis, attributed to Geber (Jabir ibn Hayyan, fl. 8th century c.e.), but written by a Christian alchemist of the late thirteenth century.

Although the idea of minima naturalia was justified in terms of Aristotelian hylomorphic theory (on the assumption that, in any characteristic combination of matter and form, the form must require a specific minimal amount of matter to work on), it is easy to see the similarity between natural minima and atoms. So, although Aristotle himself had been critical and dismissive of atomism, the rediscovery in the fifteenth century of two major sources of ancient atomism (by Epicurus, c. 341270 b.c.e., and Titus Lucretius Carus, c. 9955 b.c.e., respectively) aroused great interest among the more eclectic of Renaissance thinkers. Accordingly, Aristotelian alchemy and atomism could be used together to understand natural processes. The combination of these two traditions, which looks so unlikely on the face of it, became highly influential as a result of other Renaissance developments.

Alchemy, once thought of as distinctly inferior to the supreme Aristotelian enterprise of natural philosophy, began to earn new intellectual respect in the Renaissance. The discovery of the corpus of philosophical and theological works attributed to Hermes Trismegistus led to a reevaluation of the supposedly Hermetic alchemical writings, and indeed to magical worldviews in general. The Renaissance rediscoverers of this literature believed that its author, Hermes, identified with the Greek god of that name, must have been a great pre-Christian sage. Generally assumed to be contemporary with Moses, the Hermetic writings were regarded as one of the oldest sources of ancient wisdom, to rank alongside the Pentateuch. The alchemical writings attributed to Hermes now also won new respect, as did the pursuit of alchemy in general.

Alchemy also attracted new attention because it seemed an obvious way to understand the so-called occult qualities of matter. The Aristotelian doctrine that all bodies were composed of the four elements led to the assumption that the qualities of all bodies must derive from the manifest qualities of the four elements (heat, cold, dryness, wetness). In both alchemy and pharmacology (and therefore in medical theory more widely) it became increasingly apparent that there were other qualities that could not be reduced to the four manifest qualitiesthese were declared to be occult or hidden, and could only be known by their effects. Interest in alchemy in the Renaissance, from Paracelsus (14931541) to Francis Bacon (15611626) and even Isaac Newton (16421727), was more often motivated by a concern to understand the occult qualities assumed to reside in the smallest particles of matter, than by a desire to transmute base metal into gold.

There can be no doubt that the new admiration for alchemy and its links to theories of matter that were essentially particulate, deriving either from the minima naturalia tradition or its eclectic combination with atomism, was a major factor in the development of new theories of matter that were to play such a major role in the scientific revolution. It was by no means the only factor, however.


The revival of ancient atomism after the discovery of Lucretius's De rerum natura in 1473 gradually attracted the attention not just of alchemists but also of those working in the domain of physics. Galileo Galilei (15641642), for example, took up atomism as a way of accounting for the strength and coherence of materials, and differences between liquid and solid states. Galileo's attempts to use atomistic explanations were ultimately unsuccessful, but atomism continued to attract attention from reforming natural philosophers dissatisfied with scholastic Aristotelianism. Among the earliest of these were Pierre Gassendi (15921655), who devoted himself to a comprehensive scholarly exposition of ancient Epicurean atomism, and René Descartes (15961650).

Descartes, a mathematician at the forefront of contemporary attempts to develop a mathematical physics, was the first to see a way to predict and explain the behavior of moving bodies by assuming precisely defined laws of motion and rules of impact. By applying these same laws to invisibly small particles that were supposed to constitute all things, Descartes effectively developed a mathematized version of ancient atomism (except that Descartes did not believe the constituent particles were indivisible, and so his philosophy is more correctly called corpuscularist). This was not just a restatement of atomism, therefore, but something entirely new. It was the first presentation of what is known as the mechanical philosophy.


Descartes's version of the mechanical philosophy made a huge impact on philosophical consciousness, but although it won many adherents there were many other natural philosophers who could not accept it in its Cartesian form. The principal problem was Descartes's theory of matter. According to Descartes's strict version of the mechanical philosophy, matter was completely passive and inert. His vision of the physical universe and all its phenomena was one in which God, at the Creation, sets matter in motion and imposes the laws of nature upon it. Matter is so inert that, once set in motion, it cannot stop, but must continue to move until something else stops it. In the Cartesian universe inert particles of matter collide with one another and rebound after an exchange of motions, and all the phenomena we observe in the world are the outcome of collisions and combinations of invisibly small particles. In this system Descartes can only explain the continued coherence of an object, for example, by assuming that its particles are shaped in such a way that they can be entangled with one another, or by assuming that the constituent particles are all moving together with the same speed and direction. For many natural philosophers, this was just too implausible. What was required, such opponents of Descartes assumed, were principles of activity within the particles of matter that could account for coherence and other aspects of the behavior of matter.

It is surely significant that Descartes never showed any interest in or much knowledge of (al)chemical phenomena (even his account of biological systems depends upon what we would recognize as hydraulic and thermodynamic mechanisms, rather than supposed chemical interactions between fluids). It was those thinkers who were more aware of the complexities of alchemical and vitalistic phenomena, particularly those attributed to occult qualities, who developed alternative versions of the mechanical philosophy in which the supposed invisibly small particles of matter had their own principles of activity. This was true even of Pierre Gassendi, who saw himself simply as reviving the ancient atomism of Epicurus. There was no Epicurean precedent for Gassendi's talk of atoms with "natural impulses," "internal faculties," and "seminal powers." Robert Boyle (16271691), the leading natural philosopher in England in his day, promoted what he called the "corpuscular philosophy," which although owing much to the mechanical philosophy incorporated many doctrines from the tradition of alchemical corpuscularism.

The trend toward a mechanical philosophy in which matter was not completely inert but endowed with active principles achieved its culmination in the natural philosophy of Isaac Newton. In the Preface to his Principia Mathematica (1687) Newton expressed his conviction that all phenomena could be explained in terms of attractive and repulsive forces operating between the particles of bodies, and yet he referred to these as "mechanical principles." Descartes would never have entertained the possibility of such forces (for him gravitational fall was not due to attraction but to streams of invisible particles pushing things down toward the center of the earth), but Newton, unlike Descartes, had spent many years of his life studying the principles of alchemy.


If detailed experimental knowledge in alchemy contributed to new conceptions of the nature of matter, so did developments in medical knowledge. In part this was the direct result of alchemical ideas being used to reform medicine by thinkers like Paracelsus and Jean Baptiste van Helmont (15771644), but there were older medical traditions involved. Medical writers had always been concerned to understand the differences between life and death, between the living and nonliving. Although Aristotle noticed the link between heat and life, he denied that life was maintained by fire. Instead he attributed animal heat to the "element of the stars," since the stars were self-moving, and so, according to Aristotle, must be alive. Descartes simply insisted that the heat of the living body was nothing more than the result of a fire burning in the animal heart. William Harvey (15781657), discoverer of the circulation of the blood, by contrast, located animal heat in the blood, and asserted that blood corresponded to the element of the stars, having its own principle of life within it. Among the succeeding generation of medical writers in England were those, like Thomas Willis (16211675) and John Mayow (16411679), who tried to explain living systems in terms of the (al)chemically tempered (non-Cartesian) mechanical philosophy; and those like Francis Glisson (15971677), who was led by his discovery of tissue contractility and irritability (even in the absence of nerves) to conclude that all matter was endowed with perception, appetite, self-motility, and therefore life.

Descartes had tried to reduce all living processes to mechanistic interactions, and although he initially had some influence here, it seems safe to say that, for most thinkers, animal development and especially animal generation seemed to defeat Descartes's mechanistic ingenuity. By the eighteenth century only radically atheistic thinkers like Julien Offray de la Mettrie (17091751) and Baron d'Holbach (17231789) took the strict mechanistic line. Glisson's physiology, if not his theory of matter, was taken up by Albrecht von Haller (17081777), while post-Harveian medical research came together with the Newtonian version of the mechanical philosophy to consolidate a vitalistic theory of life that went hand in hand with a theory of matter that allowed for certain principles of activity within matter. One important ingredient in the mix emerged as a result of experimental investigations firstly of static electricity, and subsequently of current electricity. In the final paragraph of the second edition of the Principia (1713) Newton referred influentially to an electrical spirit, which he seemed to believe was not only responsible for attractions and repulsions between particles but also played a physiological role in animals.


Epicurean atomism was usually regarded as an atheistic philosophy and those natural philosophers who were associated with its revival, or indeed with any corpuscular matter theory which might be construed as atomistic, took pains to correct this view. Gassendi used all his scholarly and philosophical resources to "baptize" Epicurus and show that his philosophy was compatible with Christian doctrine. Corpuscular philosophers in England, such as Kenelm Digby (16031665), Walter Charleton (16201707), and Robert Boyle effectively began the tradition known as "natural theology" by showing how their natural philosophy could be used to prove the existence of God. Even so, the materialism of the strict versions of the mechanical philosophywhich included the system developed by Thomas Hobbes (15881679) as well as Cartesianismled many to distrust these new philosophies.

Nicolas Malebranche (16381715) and other followers of Descartes tried to assert the necessary theism of Cartesianism by suggesting that matter was so inert that it was incapable of any causal activity. A hurled brick has no power of its own to break a window, they would have suggested, and only does so because God, ensuring the perpetuation of the laws of nature, causes the glass to break on the occasion that the brick hits it. This religiously motivated "occasionalism," as it is called, was regarded as unacceptable by many orthodox believers, however, because it seemed to make God directly responsible for everything in the world, including all the most debasing and the most wicked acts of mankind.

Assumptions about the activity of matter, on the other hand, seemed to many to support the theistic cause while allowing for the transcendence of God. If matter could be shown, by experiment, to have principles of activity within it, this raised the question of how these active principles came to be there. Clearly, they could only have been put there by a supreme Creator. This argument depended upon the standard assumption that matter was, by its nature, completely passive and inert, and therefore active principles must be extraneous additions.

Unfortunately, atheists found it easy to suggest that matter was not inherently passive. Indeed, they could use Newtonian and other claims to demonstrate that it was not. Nevertheless, the most common strategy among the orthodox was to strike a balance, making matter not passive but not too active, either. Matter that was too active was also regarded as subversive to sound religion. Glisson's living matter was regarded by some leading churchmen as highly pernicious, as was John Locke's (16321704) argument that God's omnipotence allowed him to make matter capable of thinking. For such churchmen, traditional religious dualism between passive matter and active spirit had to be upheld in order to leave a significant role for immaterial spirit. Consequently, living or thinking matter had to be declared to be logical impossibilities, which not even an omnipotent God could bring about.

In Roman Catholic countries atomism confronted its own special problem. Aristotelian hylomorphism could easily account for the seemingly paradoxical fact that the bread and wine used for the Eucharist continued to look and taste like bread and wine (even though it was supposed to be actually the blood and flesh of Christ). Atomist or corpuscularist theories could not, however. As a result, Descartes's works were included on the Inquisition's Index of Prohibited Books after 1663, and from 1671 his theories could not be taught in French universities.


The mechanical philosophy and its theory of passive and inert matter, interacting only by physical collision and entanglement, has been used by recent historians to make a number of bold claims about the nature of Western civilization. Feminist historians, for example, have seen it as the embodiment of a philosophy of domination and exploitation, insensitive to organicist and ecological concerns, which has led to the current lamentable excesses of capitalistic and technological culture. Unfortunately, most of this work characterizes the mechanical philosophy as monolithically Cartesian in its nature. In these same feminist accounts, alchemy and magical worldviews are seen as being holistic and organicist, and completely antithetical to the mechanical philosophy. A more sensitive reading of the historical development of matter theory and the mechanical philosophy, showing the crucial role of alchemical and other occult ideas, suggests that the story is more complex than feminist historiography has so far acknowledged.

As the complexities of early modern matter theory have been uncovered, another once influential historiographical claim has fallen out of favor. Some historians claimed to be able to see parallels between matter theory and political belief systems in early modern England. In these accounts orthodoxy was represented in natural philosophy by the mechanical philosophy, and in politics by monarchism and episcopalianism. Radical political thinkers, republicans and those with democratic tendencies, and presbyterians or independents in religion, by contrast, were held to favor theories of active matter. There were supposed to be clear parallels between the idea of passive matter, moved from outside by an omnipotent God, and an obedient populace ruled from above by an absolute monarch. Similarly, those with more democratic political tendencies were supposed to believe that particles of matter should have their own principles of movement within them. According to this view, only those of quite extreme radical politics believed in active matter. Looking back to the recent heyday of this historiographical trend, the only thing to be said in its favor was that it stimulated historians to look more closely at the actual details of early modern matter theory. As should be apparent from the foregoing, it was not long before historians realized that the assumptions about matter theory in this historiographical tradition were hopelessly crude, if not downright wrong.

Part of the problem with both these historiographical trends is that they are based upon glib presuppositions about the nature of early modern sciencein particular assumptions that the mechanical philosophy was always and everywhere indistinguishable from Cartesianism. This in itself could be seen to stem from the fact that until comparatively recently historians of science had a tendency to concentrate on those aspects of the history of science that were presupposed on presentist grounds to contribute to modern science. Accordingly, alchemy and other occult ideas were ignored as irrelevant. Feminist historians can perhaps be forgiven, therefore, for taking such recent historical reconstructions for granted, and using them in their own accounts. The inadequacies of this approach to the history of science have now been thoroughly recognized, however, and the current trend is to try to understand natural philosophy and past science in its own terms, not in relation to modern scientific beliefs.

See also Alchemy ; Bacon, Francis ; Boyle, Robert ; Cartesianism ; Charleton, Walter ; Copernicus, Nicolaus ; Descartes, René ; Galileo Galilei ; Harvey, William ; Hobbes, Thomas ; Locke, John ; Mechanism ; Medicine ; Natural Philosophy ; Newton, Isaac ; Philosophy ; Scientific Method ; Scientific Revolution .


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John Henry