Experimental methods

Earlier this year Lego released a new set called “The Research Institute.” The Research Institute consists of three scientists with the tools of their trade: an astronomer with a telescope and star chart, a chemist with a lab bench and Erlenmeyer flasks, and a paleontologist with a, magnifying glass, a microscope and a dinosaur skeleton. This set was wildly popular. It sold out rapidly, and the four-centimeter high scientists currently have over 41,000 followers on Twitter (@LegoAcademics).


I’d like to begin this page on experimental method by reflecting on how this very popular toy represents the activities of scientists in the modern world. What is it that scientists do? One of the things that scientists do is to observe the natural world. Of course, scientists can and do observe the world with the unaided eye, but they also have at their disposal instruments that can enhance vision and other senses. The telescope and the microscope are two tools invented in the seventeenth century that made it possible for scientists to observe things that were too far away or too tiny to see with the naked eye. We have covered Galileo’s use of the telescope as an astronomical instrument. If you are interested in the microscope, see here.  So far in this course, we have explored the work and ideas of people who made keen observations of the natural world. These individuals include ancient philosophers (Aristotle and Ptolemy), Islamic scholars (Muḥammad ibn Mūsā al-Khwārizmī, Ibn al-Haytham, Ibn Rushd, Nasir al-Din al-Tusi, and Ibn al-Shatir), medieval scholastics (Nicole Oresme and John Buridan), and early modern intellectuals (Copernicus, Tycho, Kepler and Galileo). The astronomer and the paleontologist in the Research Institute thus stand in a millennia-long tradition of observational science.

But what about the other figure in the set, the chemist? The Lego chemist comes equipped with a lab bench and flasks full of brightly colored liquids. The chemist is prepared to perform experiments, another major activity that we today associate with science and scientists. What is an experiment and how is it different from an observation? Generally speaking, scientists who observe nature do not alter nature as they make their observations. Astronomers are the quintessential type of observational scientists: they can watch the movements of celestial bodies but they cannot alter these movements in any way. Experimenters, by contrast, actively manipulate the natural world. They artificially isolate natural phenomena and processes in order to study them. They create conditions that do not exist in nature in order to learn something about natural conditions. This kind of contrived or artificial manipulation of nature came to be a very important way of studying nature in the sixteenth and seventeenth centuries. Although one can certainly find examples of experiments in earlier periods, it was only in the early modern period that experiments became a prominent part of natural philosophy (or what would come to be called science.)

The dramatic rise in importance of experiments in the sixteenth and seventeenth centuries is connected to the demise of Aristotelian philosophy and to the rising status of artisans and artisanal labor. Let me take these factors in turn.

Experiments and “experimental philosophy” were associated both with the rejection of Aristotelian methods for studying the natural world as well as Aristotelian explanations for natural phenomena. Experimental methods developed in opposition to Aristotelian methodology and entailed the breakdown of certain Aristotelian categories and ways of producing knowledge. In Aristotelian methodology, knowledge claims about the natural world could be made on the basis of “experience,” but not on the basis of “experiment.” A statement such as, “heavy bodies fall,” was an appropriate basis for knowledge claims because it represented a universal, commonly held, textually verified experience. A statement such as, “On such-and-such a date in such-and-such a place I rolled a ball down a smooth plane with a certain angle of inclination and calculated the velocity,” was not appropriate because singular, unusual, contrived events such as this could not reveal the regular course of nature. They could be anomalies or misperceptions on the part of the individual observer. Experimenters rejected these claims and argued that active intervention in natural processes produced more reliable and certain knowledge about these processes tan “passive” observation. Many experimenters explicitly rejected Aristotelian physics and proposed alternative theories of matter and motion. For example, some proposed that matter was made out of small particles, called “atoms” or “corpuscles,” too small to be seen by the naked eye. All natural phenomena were the result of these particles of matter interacting with each other. Atoms or corpuscles might be different shapes and sizes. As they moved they bumped into other particles, which set these particles in motion, and these particles in turn set other particles in motion, and so on. For “corpuscularians” or “atomists” the motions of these fundamental particles were caused by the mechanical forces of particles hitting other particles, like billiard balls on a pool table. This is certainly not modern atomic theory, but it is a far cry from the four Aristotelian elements seeking their natural place in the cosmos. Another name for these anti-Aristotelian thinkers was “mechanical philosophers.” If natural phenomena were mechanical, it made sense to examine them in the way one might examine a machine. That is, it made sense to actively intervene – to take it apart, to look at parts in isolation, to test how it worked under different conditions. In other words, it made sense to experiment on it. What I’ve just sketched is a very general picture of “atomism” and “mechanical philosophy” and their relationship to “experimental philosophy.” In the sixteenth and seventeenth centuries there was tremendous variation in what it meant to be an “atomist” or a “mechanical philosopher.”

The second important factor in the rise of experimental methods was the rising status of artisans in this period. In my Introduction to this course I noted that in the ancient and medieval periods there was a sharp division between the work of the mind and the work of the hands. Pure reason was valued much more highly than practical know-how. Philosophical knowledge was purse and abstract, above the mundane, practical realities of everyday life. It was the highest form of knowledge. Practical know-how, by contrast, was about the messy and contingent world in which we live. Questions about how to increase crop yield, build bridges that would not collapse and cannons that could break down fortifications were important, but the people who could answer these questions were of lower social status than philosophers. I also noted in my introduction that this sharp distinction started to break down in the early modern period.  The sixteenth and seventeenth centuries saw the emergence of new views of labor and of the functions of technical knowledge. The artificial processes through which nature was altered and transformed by artisans were granted new significance. Now these artificial manipulations of nature were seen as a crucial way to learn about the natural world.

Anne of Denmark, by Lucas Cranach the Younger. Wikimedia Commons.

In what follows, I take two examples of early modern experimenters to illustrate the wide range of activities and theoretical commitments among sixteenth- and seventeenth-century scientists.

My first example is the sixteenth-century Danish/German scientist Anna of Denmark, Duchess of Saxony (1532 – 1585). (This paragraph is based on the excellent work on Anna of Saxony by Alisha Rankin, cited below.)  Anna was the oldest child of King Christian III of Denmark. In 1548, she married Duke August of Saxony, becoming the Duchess of Saxony. (Saxony was one of the largest and most powerful territories in the Holy Roman Empire. Sixteenth-century Saxony corresponds roughly to the modern German state of Saxony.) Anna of Saxony had a chemical laboratory where she prepared medicines. In the sixteenth century there was considerable interest in chemical remedies. Chemical remedies included medicines made out of minerals, rather than the more usual plant substances, but they also included medicines made by distilling herbs and other substances. Anna was in the forefront of chemical medicine in the sixteenth century. People from all over Europe and from all walks of life (royalty and aristocracy as well as local artisans and peasants) consulted her about medical problems ranging from fevers to stroke to hemorrhoids to infertility, and requested medicines from her distillery.  Anna learned the techniques of chemistry from another German noblewomen, the Countess Dorothea of Mansfeld (1493 – 1578). Distillation and other chemical processes required elaborate, specialized and very expensive equipment. Distillation was also a labor-intensive process, often requiring many assistants. Some of Anna’s remedies had hundreds of ingredients and took two or three years to make. Anna employed servants to manage her distillery, although she seems to have personally overseen a good bit of the work that went on. These servants were not mere technicians either. Anna’s were so well trained and trusted that she directed at least one of them to do her own experiments to modify and improve a pre-existing recipe for a remedy. Anna herself experimented with new ingredients and frequently sought to improve her remedies. Essentially, Anna was the director of a laboratory devoted to pharmaceutical research and production. Although Anna carried on extensive correspondence about her work with physicians, patients and natural philosophers throughout Europe, she never published any of her work, making her considerably less well known today than some of her contemporaries who published books.

Woman distilling, on the title page of Michael Puff von Schrick, Von allen geprenten Wassern, 1530. Photo: National Library of Medicine, Washington, D.C.
NPG D5346; Margaret Cavendish (nÈe Lucas), Duchess of Newcastle upon Tyne by William Greatbach, after  Abraham Diepenbeeck
Margaret Cavendish, by William Greatbach, after Abraham Diepenbeeck (1846) © National Portrait Gallery, London

My second example is the seventeenth-century English scientist, Margaret Cavendish (1623 – 1673). Margaret Cavendish (née Lucas) was born into a wealthy and aristocratic English family. She was highly educated, although as a woman she was not permitted to attend a university. In 1643 she married William Cavendish, the Duke of Newcastle (making her the Duchess of Newcastle). Cavendish was interested in science from a young age and wrote several books on natural and experimental philosophy. (Science fiction fans might want to take note that she wrote one of the earliest works in this genre, The Description of a New World, Called the Blazing World, in 1666.) Like many seventeenth-century scientists she rejected Aristotelian philosophy. She believed that matter was composed of tiny, sub-visible particles of different shapes and sizes. One of the distinctive features of her theory of matter is her belief that matter was animated (alive). She did not believe that mechanical forces alone could account for all of the properties of matter and all natural phenomena.  In her Observations upon Experimental Philosophy she wrote: “I cannot conceive how inanimate bodies can work upon each other, I mean such bodies as have neither life nor motion, for without life or motion there can be no action” (112).

Margaret_Newcastle_1686_Grounds_Front+TitleCavendish wrote on a wide variety of natural philosophical topics. In one of her scientific books, Observations upon Experimental Philosophy (1668), she discussed the use of the microscope, the inner structures of insects and plants, magnetism, the question of whether change is possible in the celestial realm, the rational soul, chemical principles and the plague. She commented critically on the ideas of ancient and contemporary natural philosophers, including Aristotle and Descartes. And this is just a selected list of the topics she covered! Cavendish was not unusual in the breadth of her interests. Few scientists before the nineteenth century confined themselves to particular specialties like astronomy, biology, geology or chemistry. Most ranged widely across a broad array of subjects. Cavendish

To get a sense of how experiments figured in Cavendish’s work, let’s take a closer look at the section on freezing in her Observations upon Experimental Philosophy. In this section she addresses such questions as: what causes water to freeze? what are the properties of ice? These may seem like simple questions, but recall that Cavendish and her contemporaries are among the first western scientists to reject Aristotle’s notion that water is an element. That opens up all kinds of new questions about the properties of water and ice and steam, questions that no longer have satisfactory answers.

Photo by Kathleen Crowther.

Cavendish asserts that the transformation of water into ice, snow or hail takes place at the level of its constituent particles. Under the influence of cold, the particles that make up water “contract and condense” (103). Snow particles are triangles and ice particles are square, accounting for the greater heaviness of ice. She acknowledges that some other natural philosophers believe that freezing is a process of expansion rather than contraction of the fundamental particles of water. Their evidence is the observation that glass or earthenware vessels filled with water will crack when the water inside them freezes. Further, they note that ice floats on water, which they believe means it is less dense than water. But neither of these observations is proof that water expands when it freezes, according to Cavendish. Ice is not necessarily lighter than water, she writes, “because it will float above water; for a great ship of wood which is very heavy, will swim, when as other sorts of bodies that are light and little, will sink” (105). And she counters with the observation “that some spirituous liquors of a mixt nature will not expand, but on the contrary, do visibly contract in the act of freezing” (105). These examples may sound more like “observations” than “experiments.” This is not unusual in the period, even in a book with “experimental philosophy” in the title. The line between observations and experiments was often blurry. However, Cavendish does also bring in some “artificial” processes, noting that it is possible “to turn water or snow into the figure of ice, by the commixture of salt, niter, allum, or the like” (114). She also points out that some “chemical extracts” (that is, substances extracted by distillation) will not freeze.  These examples are drawn from just one chapter in one book by Cavendish, but hopefully they give a taste of her methods.

By this point, most readers will have noticed that all of the experimenters I’ve discussed on this page (including the Lego chemist) are female. Women are, of course, active participants in scientific fields today, and they were in the past as well. Although women were barred from universities in the medieval and early modern periods (and indeed, until the twentieth century in some cases), most experiments did not take place in universities. Most experiments were performed in the homes of wealthy individuals, at courts, or in scientific societies. Homes and courts, unlike universities and scientific societies, were spaces open to women (at least women of the upper classes). Some aristocratic women sponsored scientific work, including experiments. A prime example of this type of aristocratic patron is the Christina of Lorraine, the Grand Duchess of Tuscany, who was one of Galileo’s principal supporters. But other wealthy and high born women like Anna of Saxony and Margaret Cavendish set up their own experimental equipment and participated directly in scientific work.

However, women were barred from the other major site of experimental practice: scientific societies. A number of scientific societies were formed throughout Europe in the seventeenth century. Most of them had royal or aristocratic patronage and promoted experimental work. One of the earliest of these societies was the Accademia del Cimento in Florence.

ASSIGNMENT: Read about the Accademia del Cimento and the experimenter Evangelista Torricelli (1608-1647) on the website Court Scientists set up by the Galileo Museum in Florence. Take the “Tour” and read the sections on “History” and “The question of the vacuum” (and all subsections under these).

OPTIONAL: You can read about another scientific society, the Royal Society of London, and one of its most famous experimenters, Robert Boyle (1627-91).

Sources and useful references:

J.A. Bennett, “The Mechanics’ Philosophy and the Mechanical Philosophy” History of Science 24 (1986): 1-28.

Peter Dear, Discipline and Experience: The Mathematical Way in the Scientific Revolution (Chicago and London: University of Chicago Press, 1995).

Pamela O. Long, Artisan/Practitioners and the Rise of the New Sciences, 1400-1600 (Corvallis: Oregon State University Press, 2011).

Alisha Rankin, Panaceia’s Daughters: Noblewomen as Healers in Early Modern Germany (Chicago: University of Chicago Press, 2013).

Paolo Rossi, Philosophy, Technology, and the Arts in the Early Modern Era, trans. S. Attanasio (New York: Harper & Row, 1970).

Steven Shapin and Simon Schaffer, Leviathan and the Air-Pump: Hobbes, Boyle, and the Experimental Life (Princeton: Princeton University Press, 1985).

Pamela Smith, The Body of the Artisan. Art and Experience in the Scientific Revolution. (Chicago: University of Chicago Press, 2004).

Edgar Zilsel, “The Sociological Roots of Science” American Journal of Sociology 47 (1941-42): 544-62.

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