Gassendi on the Science of Observation and the Human Soul
Pierre Gassendi (1592-1655) was a seventeenth-century French Catholic priest and philosopher. A contemporary of Descartes's, Gassendi was part of a group of intellectuals in France who sought a new philosophy of nature that could replace the traditional teachings of Aristotle that had been so severely criticized by Copernicus and his followers. Gassendi had no doubt that his faith as a Christian was compatible with his enthusiasm for the new sciences of observation, but in order to demonstrate this to his contemporaries he had to show that the mechanical explanations of the universe and the natural world did not necessarily lead to a heretical materialism or atheism. In the following passage, taken from his posthumously published work Syntagma Philosophicum (1658), Gassendi attempted to demonstrate that one might infer the existence of the human soul, even if it was not accessible to the senses.
Here are many such things for which with the passage of time helpful appliances are being found that will make them visible to the senses. For example, take the little animal the mite, which is born under the skin; the senses perceived it as a certain unitary little point without parts; but since, however, the senses saw that it moved by itself, reason had deduced from this motion as from a perceptible sign that this little body was an animal and because its forward motion was somewhat like a turtle's, reason added that it must get about by the use of certain tiny legs and feet. And although this truth would have been hidden to the senses, which never perceived these limbs, the microscope was recently invented by which sight could perceive that matters were actually as predicted. Likewise, the question had been raised what the galaxy in the sky with the name of the Milky Way was. Democritus, concerning whom it was said that even when he did not know something he was knowing, had deduced from the perceptible sign of its filmy whiteness that it was nothing more than an innumerable multitude of closely packed little stars which could not be seen separately, but produced that effect of spilt milk when many of them were joined together. This truth had become
Known to him, and yet had remained undisclosed to the senses until our day and age, until the moment that the telescope, recently discovered, made it clear that things were in fact what he had said. But there are many such things which, though they were hidden from the ancients, have now been made manifest for our eyes. And who knows but a great many of those which are concealed in our time, which we perceive only through the intelligence, will one day also be clearly perceived by the senses through the agency of some helpful appliance thought up by our descendants? . . .
Secondly, if someone wonders whether a certain body is endowed with a soul or not, the senses are not at all capable of determining that by taking a look as it were at the soul itself; yet there are operations which when they come to the senses' notice, lead the intellect to deduce as from a sign that there is some soul beneath them. You will say that this sign belongs to the empirical type, but it is not at all of that type, for it is not even one of the indicative signs since it does not inform us of something that the senses have ever perceived in conjunction with the sign, as they have seen fire with smoke, but informs us instead of something that has always been impenetrable to the senses themselves, like our skin's pores or the mite's feet before the microscope.
You will persist with the objection that we should not ask so much whether there is a soul in a body as what its nature is, if it is the cause of such operations, just as there is no question that there is a force attracting iron in a magnet or that there is a tide in the sea, but there are questions over what their nature is or what they are caused by. But let me omit these matters which are to be fully treated elsewhere, and let it be enough if we say that not every truth can be known by the mind, but at least some can concerning something otherwise hidden, or not obvious to the senses themselves. And we bring up the example of the soul both because vital action is proposed by Sextus Empiricus as an example of an indicative sign and because even though it pertains not so much to the nature of the soul as to its existence, still a truth of existence of such magnitude as this, which it is most valuable for us to know, is made indisputable. For when among other questions we hear it asked if God is or exists in the universe, that is a truth of existence which it would be a great service to establish firmly even if it is not proven at the same time what he is or what his nature is. Although God is such that he can no more come under the perusal of the senses than the soul can, still we infer that the soul exists in the body from the actions that occur before the senses and are so peculiarly
The society’s journal, Philosophical Transactions, reached out to professional scholars and experimenters throughout Europe. Similar societies began to appear elsewhere. The French Academy of Sciences was founded in 1666 and was also tied to seventeenth-century state building, in this case Bourbon absolutism (see Chapter 15). Royal societies, devoted to natural philosophy as a collective enterprise, provided a state (or princely) sponsored framework for science and an alternative to the important but uncertain patronage of smaller nobles or to the religious (and largely conservative, Aristotelian) universities. Scientific societies reached rough agreement about what constituted legitimate research. They established the modern scientific custom of crediting discoveries to those who were first to publish results. They enabled information and theories to be exchanged more easily across national boundaries, although philosophical differences among Cartesians, Baconians, and traditional Aristotelians remained very difficult to bridge. Science began to take shape as a discipline.
The early scientific academies did not have explicit rules barring women, but with few exceptions they contained only male members. This did not mean that women did not practice science, though their participation in scientific research and debate remained controversial. In some cases, the new science could itself become a justification for women’s inclusion, as when the Cartesian philosopher Franpois Poullain de la Barre used anatomy to declare in 1673 that “the mind has no sex.” Since women possessed the same physical senses as men and the same nervous systems and brains, Poullain asked, why should they not equally occupy the same roles in society? In fact, historians have discovered more than a few women who taught at European universities in the sixteenth and seventeenth centuries, above all in Italy. Elena Cornaro Piscopia received her doctorate of philosophy in Padua in 1678, the first woman to do so. Laura Bassi became a professor of physics at the University of Bologna after receiving her doctorate there in 1733, and based on her exceptional contributions to mathematics she became a member of the Academy of Science in Bologna. Her papers—including titles such as “On the Compression of Air” (1746), “On the Bubbles Observed in Freely Flowing Fluid” (1747), “On Bubbles of Air That Escape from Fluids” (1748)—gained her a stipend from the academy.
Italy appears to have been an exception in allowing women to get formal recognition for their education and research in established institutions. Elsewhere, elite women could educate themselves by associating with learned men. The aristocratic Margaret Cavendish (1623-1673), a natural philosopher in England, gleaned the information necessary to start her career from her family and their friends, a network that included Thomas Hobbes and, while in exile in France in the 1640s, Rene Descartes. These connections were not enough to overcome the isolation she felt working in a world of letters that was still largely the preserve of men, but this did not prevent her from developing her own speculative natural philosophy and using it to critique those who would exclude her from scientific debate. The “tyrannical government” of men over women, she wrote, “hath so dejected our spirits, that we are become so stupid, that
FROM MARIA SYBILLA MERIAN, METAMORPHOSIS OF THE INSECTS OF SURINAM (1705). Merian, the daughter of a Frankfurt engraver, learned in her father's workshop the skills necessary to become an important early entymologist and scientific illustrator and conducted her research on two continents.
Beasts being but a degree below us, men use us but a degree above beasts. Whereas in nature we have as clear an understanding as men, if we are bred in schools to mature our brains.”
The construction of observatories in private residences enabled some women living in such homes to work their way into the growing field of astronomy. Between 1650 and 1710, 14 percent of German astronomers were women, the most famous of whom was Maria Winkel-mann (1670-1720). Winkelmann had worked with her husband, Gottfried Kirch, in his observatory, and when he died she had already done significant work, discovering a comet and preparing calendars for the Berlin Academy of Sciences. When Kirch died, she petitioned the academy to take her husband’s place in the prestigious body but was rejected. Gottfried Leibniz, the academy’s president, explained, “Already during her husband’s lifetime the society was burdened with ridicule because its calendar was prepared by a woman. If she were now to be kept on in such capacity, mouths would gape even wider.” In spite of this rejection, Winkelmann continued to work as an astronomer, training both her son and two daughters in the discipline.
Like Winkelmann, the entymologist Maria Sibylla Merian (1647-1717) also made a career based on observation. And like Winkelmann, Merian was able to carve out a space for her scientific work by exploiting the precedent of guild women who learned their trade in family workshops. Merian was the daughter of an engraver and illustrator in Frankfurt, and she served as an informal apprentice to her father before beginning her own career as a scientific illustrator, specializing in detailed engravings of insects and plants. Traveling to the Dutch colony of Surinam, Merian supported herself and her two daughters by selling exotic insects and animals she collected and brought back to Europe. She fought the colony’s sweltering climate and malaria to publish her most important scientific work, Metamorphosis of the Insects of Surinam, which detailed the life cycles of Surinam’s insects in sixty ornate illustrations. Merian’s Metamorphosis was well received in her time; in fact, Peter I of Russia proudly displayed Merian’s portrait and books in his study.
Sir Isaac Newton’s work marks the culmination of the scientific revolution. Galileo, peering through his telescope in the early 1600s, had come to believe that the earth and the heavens were made of the same material. Galileo’s experiments with pendulums aimed to discover the laws of motion, and he proposed theories of inertia. It was Newton who articulated those laws and presented a coherent, unified vision of how the universe worked. All bodies in the universe, Newton said, whether on earth or in the heavens, obeyed the same basic laws. One set of forces and one pattern, which could be expressed mathematically, explained why planets orbited in ellipses and why (and at what speed) apples fell from trees. An Italian mathematician later commented that Newton was the “greatest and most fortunate of mortals”—because there was only one universe, and he had discovered its laws.
Isaac Newton (1642-1727) was born on Christmas Day to a family of small landowners. His father died before his birth, and it fell to a succession of relatives, family friends, and schoolmasters to spot, then encourage, his genius. In
NEWTON'S EXPERIMENTS WITH LIGHT (1672). Newton's own sketch (left) elegantly displays the way he proved that white light was made up of differently colored light rays. Earlier scientists had explained the color spectrum produced by shining sunlight through a prism by insisting that the colors were a by-product of contaminating elements within the prism's glass. Newton disproved this theory by shining the sunlight through two consecutive prisms. The first produced the characteristic division of light into a color spectrum. When one of these colored beams passed through a second prism, however, it emerged on the other side unchanged, demonstrating that the glass itself was not the cause of the dispersal. He was not yet thirty when he published the results of this experiment.
1661, he entered Trinity College in Cambridge University, where he would remain for the next thirty-five years, first as a student, then as the Lucasian Professor of Mathematics. The man who came to represent the personification of modern science was reclusive, secretive about his findings, and obsessive. During his early work with optics, he experimented with his own eyes, pressing them to see how different shapes would change the effects of light and then, intrigued by what he found, inserting a very thick needle “betwixt my eye and the bone as neare to the backside of my eye as I could” to actually curve his eyeball. (Please do not try this at home.)
Newton’s first great burst of creativity came at Cambridge in the years from 1664 to 1666, “the prime of my age for invention.” During these years, Newton broke new ground in three areas. The first was optics. Descartes believed that color was a secondary quality produced by the speed of particulate rotation but that light itself was white. Newton, using prisms he had purchased at a local fair, showed that white light was composed of different-colored rays (see image on this page). The second area in which Newton produced innovative work during these years was in mathematics. In a series of brilliant insights, he invented both integral calculus and differential calculus, providing mathematical tools to model motion in space. The third area of his creative genius involved his early works on gravity. Newton later told different versions of the same story: the idea about gravity had come to him when he was in a “contemplative mood” and was “occasioned by the fall of an apple.” Why did the apple “not go sideways or upwards, but constantly to the earth’s center? . . . Assuredly the reason is, that the earth draws it. There must be a drawing power in matter.” Voltaire, the eighteenth-century French essayist, retold the story to dramatize Newton’s simple brilliance. But the theory of gravity rested on mathematical formulations, it was far from simple, and it would not be fully worked out until Principia, more than twenty years later.
Newton’s work on the composite nature of white light led him to make a reflecting telescope, which used a curved mirror rather than lenses. The telescope earned him election to the Royal Society (in 1672) and drew him out of his sheltered obscurity at Cambridge. Encouraged by the Royal Society’s support, he wrote a paper describing his theory of optics and allowed it to be published in Philosophical Transactions. Astronomers and scientists across Europe applauded the work. Robert Hooke, the Royal Society’s curator of experiments, did not. Hooke was not persuaded by Newton’s mode of argument; he found Newton’s claims that science had to be mathematical both dogmatic and high-handed; and he objected—in a series of sharp exchanges with the reclusive genius— that Newton had not provided any physical explanation for his results. Stung by the conflict with Hooke and persuaded that few natural philosophers could understand his theories, Newton withdrew to Cambridge and long refused to share his work. Only the patient effort of friends and fellow scientists like the astronomer Edmond Halley (1656-1742), already well known for his astronomical observations in the Southern Hemisphere and the person for whom Halley’s Comet is named, convinced Newton to publish again.
Newton’s Principia Mathematica (Mathematical Principles of Natural Philosophy) was published in 1687. It was prompted by a visit from Halley, in which the astronomer asked Newton for his ideas on a question being discussed at the Royal Society: was there a mathematical basis for the elliptical orbits of the planets? Halley’s question i nspired Newton to expand calculations he had made earlier into an all-encompassing theory of celestial—and terrestrial— dynamics. Halley not only encouraged Newton’s work but supervised and financed its publication (though he had less money than Newton); and on several occasions he had to persuade Newton, enraged again by reports of criticism from Hooke and others, to continue with the project and to commit his findings to print.
Principia was long and difficult—purposefully so, for Newton said he did not want to be “baited by little smatterers in mathematics.” Its central proposition was that gravitation was a universal force and one that could be expressed mathematically. Newton built on Galileo’s work on inertia, Kepler’s findings concerning the elliptical orbits of planets, the work of Boyle and Descartes, and even his rival Hooke’s work on gravity. He once said, “If
I have seen further, it is by standing on the shoulders of giants.” But Newton’s universal theory of gravity, although it drew on work of others before him, formulated something entirely new. His synthesis offered a single, descriptive account of mass and motion. “All bodies whatsoever are endowed with a principle of mutual gravitation.” The law of gravitation was stated in a mathematical formula and supported by observation and experience; it was, literally, universal.
The scientific elite of Newton’s time was not uniformly persuaded. Many mechanical philosophers, particularly Cartesians, objected to the prominence in Newton’s theory of forces acting across empty space. Such attractions smacked of mysticism (or the occult); they seemed to lack any driving mechanism. Newton responded to these criticisms in a note added to the next edition of the Principia (General Scholium, 1713). He did not know what caused gravity, he said, and he did not “feign hypotheses.” “For whatever is not deduced from the phenomena must be called hypothesis,” he wrote, and has “no place in the experimental philosophy.” For Newton, certainty
NEWTON AND SATIRE. The English artist and satirist William Hogarth mocking both philosophy and "Newton worship" in 1763. The philosophers' heads are being weighed on a scale that runs from "absolute gravity" to "absolute levity" or "stark fool."
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