In retrospect: The Sceptical Chymist

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Robert Boyle's widely misunderstood book elevated the status of chemistry, explains Lawrence Principe.

The Sceptical Chymist

Robert Boyle
First published 1661. ISBN: 9780554396620

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It can be said of books, as Shakespeare said of people, that “some are born great, some achieve greatness, and some have greatness thrust upon them”. Robert Boyle's The Sceptical Chymist (1661) falls into the last category. Widely celebrated as a landmark, it remains misrepresented, misunderstood and unread. It has been praised for opening the way to modern chemistry by sweeping away misguided alchemy and for providing the first modern definition of an element. Yet it did neither. Both Boyle and the book are important, but not for the reasons often cited.

Boyle (1627–91), seventh son of the richest man in Britain, devoted his life and fortune to the study and advancement of science and Christianity. At his sister's Pall Mall address in London where he lived much of his adult life, he performed countless experiments, received visitors and colleagues, and wrote many books. The Sceptical Chymist was Boyle's fourth volume, following a devotional treatise, a collection of chemical essays and an account of experiments performed with the 'Pneumatick Engine', or air-pump. That device, built for him by Robert Hooke, led to the enunciation of the inverse relationship between the pressure and volume of gases, later named Boyle's law.


Far from defining the chemical elements, Robert Boyle in fact doubted their existence.

The Sceptical Chymist is not an easy read. Begun as a dialogue among proponents of various chemical systems, the book is an unpolished pastiche of several unfinished works. It is prolix, repetitive, disjointed and occasionally contradictory.

Boyle's goals were to question some commonly held chemical theories, to make chemical practitioners more “philosophical” and less commercially focused, and to raise chemistry's status. In his day, the field was held in low esteem; it had no place at universities, its practice was dirty, smelly and laborious. Chemical techniques were used mainly to produce medicaments, a situation preserved in the British usage of the word chemist to mean pharmacist. Chemical textbooks were predominantly lists of pharmaceutical preparations. Boyle believed that chemistry should be much more. For him, it was the key to understanding nature.

Boyle held that chemical pharmacists and textbook writers — the vulgar chymists as he called them — relied on unsound ideas. Chief among them was the concept, advanced by the sixteenth-century medical reformer Paracelsus, that all substances were composed of three essential components. Paracelsians based this belief on their finding that organic materials could be distilled to provide volatile, inflammable and saline fractions, which they named Mercury, Sulphur and Salt, respectively. Boyle argued that these could not be isolated from all materials, and were produced rather than separated by the distilling fire. Hence, they could not be universal principles. Moreover, when the vulgar chymists thought they were concentrating the 'essence' of something by distillation, they were reducing its therapeutic value through thermal decomposition.

“Boyle's view supported the alchemists' goal of transmuting base metals into gold.”

Boyle drew on a long chemical tradition for his arguments. A generation earlier, Joan Baptista van Helmont, one of the most influential chemists of the seventeenth century, had expressed the same sceptical views about fire analysis and the three principles. Indeed, contemporaneous readers viewed The Sceptical Chymist as a popularization of van Helmont, who proposed that all substances were produced by modification of a single primordial principle — water. Boyle likewise attributed everything to a single stuff, which he called Catholick matter. Differences in the shape, size and motions of minute particles of this matter gave rise to the diverse substances of the world, and changing these characteristics using chemistry could transform any material into any other one. So rather than defining chemical elements as we know them, Boyle doubted that there were any. His view, moreover, supported the alchemists' goal of transmuting base metals into gold.

Although misrepresented by later generations as magical or fraudulent, alchemy was in Boyle's day a serious means of investigating nature. Alchemy had an important and positive role in the history of science. Boyle first learned chemical ideas and practices (and studied van Helmont) under the tutelage of George Starkey, an immigrant from America and graduate of Harvard College. Using the pen-name Eirenaeus Philalethes, Starkey wrote influential books on transmutation and devised a sophisticated theory of matter. Boyle himself strove to prepare the philosophers' stone, the secret substance able to transmute metals; he recounted how he had witnessed a demonstration of its powers and tested the gold it produced. He even petitioned Parliament successfully in 1689 to repeal a law forbidding gold-making, which he thought impeded research towards discovering the secret of the stone.

Far from repudiating alchemy, The Sceptical Chymist cites alchemical texts and theories to criticize the vulgar chymists. In the 1680 second edition, Boyle referred respectfully to “a much higher order” of chemists “able to transmute baser Metalls” and do things that less-skilled chemists “have judg'd impossible”. Although Boyle expressed frustration at the secrecy of alchemical authors, he also thought of them as preferable to and possessed of greater knowledge and expertise than the “meer operators” against whose “unphilosophical” practice his book was directed.

The Sceptical Chymist was neither the most widely read nor the most important of Boyle's works. Its fame was thrust upon it by retrospective attempts more than two centuries after its publication to locate a revolutionary moment for chemistry. This view attributed to Boyle innovations that later generations thought were important — such as the definition of an element and the repudiation of alchemy — but which were far from Boyle's mind. Those attempts worked only because few cared to wade through Boyle's prose and still fewer took time to recognize his motives. Besides, such revolutionary moments exist mostly in the minds of those who imagine that science develops by sudden leaps made by isolated geniuses rather than by slow, laborious steps accumulated and shared by many talented workers.

The Sceptical Chymist was one facet of Boyle's larger project to elevate the status of chemistry, to free it from servitude to medical and commercial endeavours, and to use it for exploring and explaining the hidden workings of nature. Today, chemistry continues to serve the basic physical needs of society and the intellectual and methodological needs of other sciences more than any other discipline. Even as it continues to struggle with its identity in the ever-changing landscape of modern science, chemistry has become established as an independent, fundamental and philosophical discipline. Boyle, although sceptical of elements and convinced of alchemy, played a key part in this achievement.

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