For example, suppose we have a theoretical gas confined in a jar with a piston at the top. The initial state of the gas has a volume equal to 4. With the temperature and number of moles held constant, weights are slowly added to the top of the piston to increase the pressure. When the pressure is 1. The product of pressure and volume remains a constant 4 x 1.
At this time even the idea of an experiment was controversial. The established method of 'discovering' something was to argue it out, using the established logical rules Aristotle and others had worked out 2, years before. Boyle was more interested in observing nature and drawing his conclusions from what actually happened.
He was the first prominent scientist to perform controlled experiments and publish his work with details concerning procedure, apparatus and observations. He began to publish in and continued to do so for the rest of his life on subjects as diverse as philosophy, medicine and religion.
It is Boyle's Law for which he remains most famous. This states that if the volume of a gas is decreased, the pressure increases proportionally. Understanding that his results could be explained if all gases were made of tiny particles, Boyle tried to construct a universal 'corpuscular theory' of chemistry. He defined the modern idea of an 'element', as well as introducing the litmus test to tell acids from bases, and introduced many other standard chemical tests.
He agreed with Bacon that the natural world was too complex for the categorical syllogism to penetrate. He thought that scientific progress requires an inductive method that posits a hypothesis that can then be tested by experiment involving multiple controlled observations. Because the theories could be modified in light of new empirical evidence, Boyle believed the experimental method was fundamentally superior to the scholastic syllogistic model of science.
This early modern philosophical movement sought to explain natural phenomena in terms of matter and motion, rather than, for example, the composition and proportion of Aristotelian terrestrial elements.
Boyle thought mechanical explanations were inherently more intelligible than explanations based on the elemental model because they appealed to properties which themselves were more intelligible, such as size, shape, and motion, rather than to ultimately obscure causes such as real qualities or substantial forms. For Boyle, generation, corruption, and alteration could all be explained mechanically, as various types of interaction between microscopic particles of matter he called corpuscles.
When fire-analysis experiments revealed that some compound bodies could be reduced to five, rather than only four, homogenous elements, some natural philosophers thought this was evidence of a fifth element. Boyle rejected the elemental explanatory model altogether. In a similar way, Boyle also rejected the Aristotelian notion of natural motion. In Book 8 of the Physics, Aristotle argued that each element has a natural location in the universe and a natural tendency to return to this location.
This was used to explain such things as why rocks fall and smoke rises. In contrast, Boyle argued that all matter was essentially passive and insensible, lacking any tendencies or dispositions beyond its mechanical properties. Matter can be acted upon but contains no internal force, source of motion, substantial form, or disposition.
The traditional Aristotelian qualities of hot, cold, wet, and dry could be mechanically explained in a similar way. For example, Boyle thought that heat was not a primary quality of matter, but instead a property that is reducible to a particular type of rapid corpuscular motion. The conception of heat as molecular motion is a direct descendent of this view.
In a similar way, Boyle thought the power of a key to open a lock is not due to some real quality, substantial form, or occult power of the key; rather, it is an emergent power, ultimately reducible to the size, shape, and motion of the key and the lock, which Boyle called their mechanical affections.
Boyle coined the term Mechanical Philosophy and used it to describe any attempt to explain natural phenomena in terms of matter and motion, rather than in terms of substantial forms, real properties, or occult qualities. For Boyle, this included the work of a wide variety of philosophers that otherwise differed in many respects.
His list of mechanical philosophers included the ancient atomists Democritus, Leucippus, Epicurus, and Lucretius—names synonymous with atheism at the time—as well as his contemporaries Galileo, Descartes, Gassendi, Hobbes, Locke, and Newton.
In the Origin of Forms and Qualities , among other works, he argued that our senses provide a representation of an independently existing, external physical world, which is ultimately composed of material particles moving through empty space.
Boyle held that these corpuscles have mechanical affections, properties such as size, shape, and motion, which are the primary qualities of matter, real properties that exist in any bit of material substance, no matter how small. The secondary qualities we perceive, such as color, sound, taste, odor, and warmth, are mental perceptions that are produced by these primary qualities causally interacting with our sense organs, but do not actually exist as real qualities in the object of perception itself.
Thus, perception involves information about the external world entering the brain as a result of the causal interaction between the conscious perceiver and the object perceived. Boyle thought God has the power to infinitely divide matter, even if this is beyond our rational comprehension, but the actual physical world is composed of minima or prima naturalia , microscopic particles of matter which never are, as a matter of fact, divided. These basic corpuscles interact and combine to form larger and larger clusters until they form the ordinary macroscopic material substances with which we are familiar.
He also held that there is no real distinction between a substance and its attribute. Just as there is no body that lacks extension, Descartes held that there is no extension that lacks body. Descartes held that the universe was a plenum, completely filled with material substance. Boyle thought theory had to be subordinate to observation.
Extension, rather than being the essence of matter through which all other properties were mere modifications, is only another empirically manifest mechanical affection like size, shape, texture, arrangement, and solidity. For Boyle, empty space is not only logically possible but also empirically corroborated by experiments like those performed by Torricelli, Otto von Guericke , and himself, with Robert Hooke.
Boyle also thought motion in empty space was more intelligible than in a plenum. Descartes had to resort to a complex theory of circular motion to explain it. Boyle believed that mechanical explanations were inherently more intelligible than those of the Aristotelians or the Paracelsians because they involved easily understandable concepts like size, shape, and motion.
He thought the local motion involved in the mechanical interaction of corpuscles is inherently more intelligible than the Aristotelian conception of motion as the actualization of a potential. Boyle thought the appeal to substantial forms in natural philosophy produced explanations that were vacuous when compared to mechanical explanations. However, explanations that appealed only to mechanical properties were clear, intelligible, and often had the advantage of being empirically testable.
In About the Excellency and Grounds for the Mechanical Hypothesis , Boyle points out that no one appeals to substantial forms when mechanical explanations are available, as, for example, when one is shown how the moon is eclipsed by the shadow caused by the position of the earth relative to the sun.
Likewise, there is no reason to appeal to witchcraft to explain how a concave mirror can project the image of a man into the air, once catoptrics is understood.
Boyle thought Aristotelians and Paracelsians failed to realize that this mechanical approach can be applied to natural phenomena in general. Boyle was interested in occult qualities, natural phenomena in which the effect is observable, but the cause is not, such as magnetic and electrical attraction. Boyle thought such phenomena could be explained mechanically in terms of corpuscular effluvia, the emission of small corpuscular clusters.
In A Discourse of Things above Reason , though, Boyle also recognized that some phenomena cannot be mechanically explained. These included the miracles featured in the Bible, as well as more traditional philosophical problems such as whether or not matter is infinitely divisible, how mind-body interaction is possible, and how human free will and moral responsibility can be compatible with divine foreknowledge.
Perhaps these might be explained by future philosophical investigation, but they resist straightforward mechanical explanation. This influence is apparent in his metaphysical views on the nature of substance and causation, his defense of the corpuscular hypothesis, his epistemological views on role of experiment in scientific explanation and the limits of reason, and his theological views on the importance of studying the book of nature and its potential for medicine.
Boyle is considered by many to be the father of modern experimental chemistry. Through years of diligent work he became a skilled chemist. His interest and work in chemistry lasted from the early s to the end of his life. His social status and efforts to show that natural philosophy was a theologically acceptable pursuit did much to make the science of chemistry socially respectable.
In The Sceptical Chymist , Boyle points out the limitations of fire analysis as a universal method of separating compound substances into their homogenous components, a method many Aristotelians and Paracelsians used. For example, a green stick burned in open fire seems to separate into four homogenous parts, demonstrating its compound nature: The smoke was the element of air being separated, the hissing and snapping of the sap indicated the water element, the quantity of fire grew as the stick burned, and the remaining ash was the element of earth that was left.
Pacracelsians had a similar explanation, separating the stick into the chemical principles of salt, sulfur and mercury. Boyle thought the separation could be better explained by the rapid mechanical bombardment of corpuscles from the fire onto the structure of the corpuscles composing the stick, setting them in motion.
Chemical analysis revealed that the smoke and ash are not homogenous elements but are compound bodies themselves. Some compound substances, such as gold, could be burned for extended periods at extreme temperatures without separating into other homogenous substances. Furthermore, chemical distillation of other compound substances, such as raisins, could produce five homogenous substances.
Boyle was able to chemically sublimate several substances, such as sulfur, turning them from a solid state to a gas and back without going through a liquid phase. Boyle thought such experiments had serious consequences for the elemental model since, according to it, the release of a gas involved the separation of an element or chemical principle, which would require a diminution of the whole. If a substance can be turned back and forth from a solid to a gas again and again without any sign of disintegration, then such a diminution clearly has not taken place.
The only alternative explanation on the elemental model would be that the substance has transmuted back and forth into different elements. However, if this is the case, then neither can be considered a true element. Others, such as the Philosophical History of Minerals, never came to fruition, though much of the research was completed.
These projects were records of chemical experiments and other empirical observations concerning the given substance. The goal was to create a sort of publicly accessible database of the chemical analysis of every known substance. Concerning salt, a basic chemical principle according to the Paracelsians, Boyle claimed to be able to distinguish three different kinds, each of which he could chemically produce. Boyle believed colors were caused by the mechanical properties of material corpuscles.
He also analyzed samples of phosphorous he had acquired, which produce light chemically. Boyle achieved significant success in these endeavors, though this pales in comparison to the success of later philosophers on the nature of color. This line of investigation also led Boyle to discover things not directly related to color, such as a reliable method of distinguishing an acid from a base. Developing an interpretation of a laboratory accident of Hennig Brandt, in Boyle saturated some coarse paper in phosphorous and drew a stick coated with sulfur across it, creating a steady flame.
This was the first friction match. The creation of a reliable and eventually safe way to easily produce fire was a major technological advancement that changed the world.
Boyle spent the last twenty years of his life engaged, often with the help of Ranelagh, in the chemical analysis of medical recipes. These efforts did much to bring chemistry out of the shadows of alchemy and into the light of social respectability. Throughout his work in chemistry, Boyle advocated openness in the publication of experimental results, including even those experiments that were unsuccessful. Nonetheless, there were exceptions to this openness involving alchemy.
Many of the early modern philosophers, most notably Isaac Newton, had a significant interest in alchemy, and Boyle was no exception.
Though Boyle often tried to distance chemistry from its alchemical association, many of his projects in natural philosophy were clearly alchemical. Boyle believed it was possible to transmute one substance into another, and this included the traditional alchemical quest of turning lead into gold.
He believed the possibility of transmutation directly followed from the mechanical philosophy. If there is only one universal type of matter, and the differences between the macroscopic substances we perceive are the result of structural differences at the microscopic level, then it follows that causing changes in the structure and arrangement of corpuscles might cause substantial changes at the macroscopic level.
Since gold and lead have similar macroscopic properties, there might be only a subtle difference between them at the microscopic level. Boyle claimed to have witnessed the transmutation of lead into gold on more than one occasion. Boyle also claimed to have turned gold into a base metal, using a powder given to him by a mysterious stranger.
In some works, Boyle describes successful transmutation experiments on other substances. Boyle spent a great deal of time, effort, and financial resources in these pursuits, which included searching for the elixir of life, a medicine capable of curing all diseases and extending the human lifespan. Boyle was hoodwinked on more than one occasion by charlatans who claimed to have alchemical knowledge or the rare substances required for his alchemical pursuits.
The most notable incident involved a con man named Georges Pierre. Boyle eventually realized he was being had, and there is evidence that he was aware of the danger of such scams and viewed them as an unfortunate but necessary risk in the pursuit of alchemical knowledge, a risk that his unique wealth allowed him to take.
This allowed his experiments to be reproduced and the knowledge acquired to be used to help people, especially in areas such as medicine, where the benefit to the public was obvious and immediate. There were limits to this support of scientific openness, though. For example, Boyle was concerned that the publication of instructions for turning lead into gold could collapse the world economy, bringing social chaos.
Boyle had anticipated this and left detailed instructions in his will to prevent it. The sort of secrecy involved here, however, was a part of the cost of networking with other alchemists to share recipes and other experimental data, and was considered common practice in the world of alchemy. Most alchemists were secretive, and would exchange recipes and materials only if their secrets were kept.
Boyle was justified in believing that, if he had refused to make such promises, other alchemists would not have shared their work with him. Nevertheless, this is a notable exception to his otherwise deep aversion to taking oaths, as well as his Baconian belief that scientific data should be open to the public for the benefit of humanity.
Boyle also had a deep interest in medicine. Though he never formally studied it, much of his research in natural philosophy was either directly medical in nature or motivated by medical goals, both practical and theoretical. He nonetheless distrusted physicians, after an event in his youth in which he became gravely ill when a physician at Eton gave him the wrong medicine by mistake.
Furthermore, he generally rejected their Galen-based theories in favor of mechanical ones. At the same time, Boyle knew, respected, and was respected by many of the leading physicians of his day. He sometimes even asked Boyle and Ranelagh to accompany him on house calls. While the two should not be conflated, as Boyle worked on many nonmedical projects in natural philosophy, neither can be fully understood apart from the other.
Though Boyle worked on medical projects throughout his scientific career, a renewed interest in medicine began in the late s. He would go on to steadily publish books on medical topics for the rest of his life, including Memoirs for the Natural History of Human Blood , Of the Reconcileableness of Specifick Medicines to the Corpuscular Philosophy , Some Receipts of Medicines , Medicina Hydrostatica , Experimenta et Observationes Physicae , and Medical Experiments Boyle worked with Locke on a few medical projects that are worth noting.
Though early 21 st century scholars remember Locke primarily for his work in epistemology and political philosophy, he considered himself first and foremost a physician. Boyle and Locke collaborated for several years to create a Baconian experimental history of human blood. Their work was interrupted while Locke was travelling or Boyle was ill, but their persistence resulted in the publication of Memoirs for the Natural History of Human Blood A second medical project with Locke was the collection of data for testing the miasma theory of disease.
This is particularly noteworthy because this theory proposes the mechanical explanation that disease is caused by noxious vapors moving in the air. The theory holds that these vapors act as a contagion, penetrating the bodies of those who come in contact with them through respiration. Boyle believed the contagions were composed of corpuscles and might originate deep underground, being released by human activity such as mining. Boyle and Locke hypothesized that these noxious corpuscular emanations were then spread far and wide by the wind.
Believing disease and weather were linked, they collected data from physicians across the country on both the weather and the patients they had treated, looking for correlations. Despite this, Boyle was still part of a general effort to cure the plague that included Ranelagh, Sydenham, Locke, and many others.
Boyle spent the last twenty years of his life engaged in medical research with his sister, Katherine Ranelagh. Through their vast network of correspondents, they would find medical recipes which they would then chemically analyze.
Through medical research, Boyle found the clearest way to wed his passion for natural philosophy with his philanthropic goals. Although he sometimes exaggerated his poor health, Boyle also suffered from very real and serious ailments including malaria, edema, seizures, kidney stones, toothaches, and deteriorating eyesight. Boyle considered these ravings both a medical condition and a moral defect and spent years seeking a remedy.
Since Boyle distrusted doctors and was an expert chemist, he often treated these illnesses with his own concoctions, sometimes making his condition worse. In , Boyle suffered a severe stroke that left him partially paralyzed. He eventually recovered most of the mobility he had lost and continued working on his experiments.
In , Evangelista Torricelli, a friend and advocate of Galileo, filled a glass tube with mercury, turned it upside down, and placed it in a basin of mercury. The level of mercury in the tube lowered, but some mercury remained in the tube, suspended by the weight of the air—the air pressure—pressing down on the surface of the mercury in the basin.
Since the tube was airtight, Torricelli reasoned that the area in the tube above the mercury must be a vacuum. Through Marin Mersenne and his vast correspondence network, news of the experiment quickly spread throughout Europe. Otto von Guericke heard of the Torricelli experiment and designed a pump capable of producing an evacuated receiver so strong, due to the outward air pressure, that sixteen horses could not pull the two hemispheres of the receiver apart. Boyle designed an improved model which featured a chamber made of glass, allowing direct observation of the phenomena within the evacuated receiver.
Boyle first approached the scientific instrument-maker Ralph Greatorex to build it, but when he failed Hooke took up the difficult challenge and succeeded. From the spring through the fall of , Boyle and Hooke performed dozens of experiments using the air pump and published the results in New Experiments Physico-Mechanical Touching the Spring of the Air and its Effects In this book, Boyle provides extremely detailed presentations of 43 of the experiments, giving compelling evidence for such claims as that air is a distinct substance from space, that air is elastic and has a spring, and that air pressure is so powerful that a glass vial of water placed in the receiver explodes when the air is removed.
They demonstrated that air is required for phenomena such as combustion, respiration, and sound. They even placed a Torricellian barometer in the receiver, showing that the mercury does not remain suspended in the vacuum. With its success, Boyle went from being an amateur gentleman interested in natural philosophy to being the leading scientist of the day. At many of the early meetings of the Royal Society, Boyle was asked to replicate some of the experiments.
Unlike other natural philosophers, Boyle had the financial resources to conduct the experiments and to repair the temperamental air pump when it broke. He even had an additional air pump made at considerable expense, which he gave to the Royal Society on May 15, The book was also controversial, and it remains so to this day. Steven Shapin and Simon Schaffer explore the social construction of science, using the controversy between Hobbes and Boyle over the air pump experiments as their focal point in their influential book Leviathan and the Air Pump: Hobbes, Boyle and the Experimental Life The Jesuit Priest Francis Linus tried to replicate some of the experiments and offered an alternative Aristotelian interpretation of the results, defending the view that nature abhorred a vacuum in Treatise on the Inseparable Nature of Bodies Christiaan Huygens also reported that he could not replicate some of the experiments.
Boyle praised Linus for his use of experiment, but pointed out the defects in his experimental practice in A Defense of the Doctrine Touching the Spring and Weight of the Air
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