Basic idea: Mechanism: DesCartes

Transcription

1 Basic idea: Mechanism: What does it matter? The cosmos is a machine, made up of small parts, functioning mechanically Each part has shape, size, quantity, and motion. Motion is transferred, and maintained, in the universe by contact between the constituent parts of that machine Bodies are made up of very small parts, whether atoms or corpuscles. All regular activities within the cosmos can be seen in terms of the interaction of these particles or the bodies which they constitute. Matter is completely inert. Motion is separate from matter itself. The world is completely full of matter or particles. Motion produces vortices of resultant motion around whatever is moving. The amount of motion in the universe is constant. DesCartes Gassendi: Matter is made of indivisible parts called atoms. All matter is endowed with a principle of action or force. Some atoms (at least) possessed a seminal power or internal force producing growth and change. More compatible with biology, and theology than DesCartes and Greek Atomism. Leibniz: Matter is nothing more than primitive active force. Motion is a manifestation of changing relationships between material bodies. Vis viva, the effect of motion, not motion itself, is conserved throughout the Universe. God, in making matter, was constrained by what matter, by definition, is -- activity. Matter can be nothing but active, and God could not have made it another way. Produces a potential distance between God and the Universe. Newton: Sometimes called a semi-mechanist Universe consists of matter and principles of activity added to it by God. Newton s work was made possible by observations he made in his alchemical experiments. Newton also believed that the Son of God, Jesus, was the essential principle which held actively held the universe together and supplied it with motion at all times. Newton s universe allowed for occult forces to explain the effects of force at a distance. What these forces are is irrelevant, their existence can be proven. Alchemy and Theology were the basis of Newton s acceptance of force at a distance. Newton s theories came to dominate the course of modern science, but divorced from the theology and alchemy which made it possible initially. 1

2 Significance of Mechanism: Marks a definite break with the past and sets the seal on the scientific revolution. A phenomenon largely of the mid to end of the 17th c. which dominates until the 20th c. Adoption is slow, older trends linger. Introduces the potential for confining causes within the observable cosmos. Consequently, produces our modern tendency to speak of Scientific Explanations, rather than supernatural. Sets the stage for the rise of atheist systems and later, atheism. Science in the Enlightenment Natural Philosophy goes Public An age of light: the triumph of the rational: In the Renaissance, Petrarch developed the concept of a dark age of ignorance and barbarism which preceded his own era, marked by the return of the light of knowledge and civilization. For Renaissance thinkers the Light which was returning was the civilization of classical Greece and Rome, and the original form of Christianity. As with the Renaissance, the Enlightenment was an era which defined itself: Intellectuals believed that the world (meaning all of Europe) was entering a new age of light after darkness. The Light of the Enlightenment was human reason. The Enlightenment, then, refers to a change in attitude. What was being left behind, in the minds of the self-identified Enlightenment intellectuals was all that was irrational or superstitious (including irrational forms of religion.) What was developing, according to these intellectuals was a rational and systematic approach to the world and human knowledge. By the end of the Enlightenment, the term science was in common use and we can see the emergence of the scientific world view, in which all things had to be demonstrable to reason and the senses to be believed. ancient Ascent of man Enlightenment View of History medieval stagnation Or fall Renaissance and Scientific Revolution Enlightenment Modern Triumph of Human Reason The Enlightenment is seen as the dawn of a final epoch, in which human reason triumphs over the irrational elements which held man back and subjected his fate to the whim of nature and superstition. Pre-History of the Enlightenment The Intellectual trend of the seventeenth century had had been toward a systematization of thought in regard to nature and the study of nature. Newton fused the Baconian tendency of looking for natures laws in observable phenomena and experimentation, with DesCartes tendency to explain the Universe mathematically, as a single predictable system. Now the universe could be said to operate according to set laws which were both observable and mathematically consistent. Newton is one example of a broader trend that included others such as Leibniz, and Hooke in regard to natural philosophy, Locke and Hobbes in regard to politics, and Spinoza and Locke (again) in regard to metaphysics and religion. Everywhere, to those who observed from a distance, the subjects of human inquiry were being systematized and improved by the light of reason. The big names of science and philosophy in the seventeenth century become celebrated as the sources of a new age when their ideas become popular in the eighteenth century. The Enlightenment is best seen as the eighteenth century development of these intellectual trends. Key Features of the Enlightenment: 1. Faith in the scientific method, or the Rules of Reason, as the means to establish truth. 2. The belief in progress as an axiom of modern history. 3. Belief that the scientific method could be applied to all aspects of intellectual activity (including society and morals.) 4. Skepticism in regard to the claims of religion (especially in light of the religious wars of the seventeenth century.) 5. A popularization of science and philosophy among the growing bourgeoisie or middle class, as more and more people became literate. 6. The shared goal of a triumph over nature by human achievement. 2

3 Religious Skepticism One of the most widely-recognized features of the Enlightenment (largely because of the Christian reaction against it.) It was a (rather visceral) reaction to the perceived failure of religion in the seventeenth century wars. It was also the result of the ability to construct a model of the universe based upon natural law. By the first years of the nineteenth century, Pierre Laplace could boldly say that he had no need of the hypothesis of God in his astronomy. It is also one of the features of the Enlightenment most overstated by later generations. There were few genuine atheists produced by the Enlightenment, but a legion of deists and agnostics. As David Hume said, he was too skeptical to be an atheist. It is important to remember that having issues with received religion does not imply a rejection of the idea that religion is good and necessary in society. Whatever religion there was, however, it would be best if it were rational, meaning subjected to human reason and not merely its own claims of authority. In England, this meant the development of Unitarianism (keep this in mind as we study Darwin and Victorian England.) Immanuel Kant and the Place for Faith Immanuel Kant ( ) Prussian philosopher of the Enlightenment, lived his whole life within a few miles of the city of Koenigsberg. Deist. Among his vast contributions to the development of philosophy, Kant drew what became a very popular line between that which can be subjected to human reason (the realm of the phenomenal) and that which is the stuff of meditation beyond the sphere of experience (the noumenal). In so doing, Kant was consciously following a distinction used in the seventeenth century, by Robert Boyle and others of the English Royal Society. Kant s philosophy pitched this idea in a new key -- not merely stating that there is a difference between the knowable and the transcendent, but also establishing a valid place for both science and religion in light of Enlightenment skepticism. Kant s position was more typical of Enlightenment thought than outright atheism. The Popularizers: First Example Bernard de Fontenelle s Conversations on the Plurality of Worlds. (1686) Set as a casual conversation between a man and a woman in which the man explains, in simple terms, the significance of the recent developments in astronomy leading to the triumph of the Copernican Theory. Typical Quotation: There came on the scene one Copernicus, who made short work of all those various circles, all those solid skies, which the ancients had pictured to themselves. Fired with the noble zeal of a true astronomer, he took the earth and spun it very far away from the center of the universe, where it had been installed, and in that center he put the sun, which had a far better title to that honor. Raised the tantalizing question: If the planets are other worlds like our own, might they not have life like ours? (That one had legs.) A good example of how accurate history, and scientific theory itself, can suffer when it is subjected to a marketing strategy. The Popularizers: Second Example The Encyclopedia: The Rational Dictionary of the Sciences, the Arts, and the Crafts ( ) Edited by Denis Diderot and Jean d Alembert. An ongoing project to place the advances in science, technology, and learning in ready reach of a literate public. Sought to be comprehensive. Had the open goal of destroying error and superstition. The editors marshaled serious scholars and experts in all fields to contribute. Represents a much more responsible approach to the topics than Fontenelle. However: Reading the Encyclopedia reveals a great deal less unity than its architects had hoped. What is rational for one author is absurd for the next. Had another nasty side effect of giving the impression that knowledge was finite and could be contained. Eventually the additions to, and revisions of, the encyclopedie overbalanced the project: At more than 66 volumes in its final edition, the attempt to catalog all human knowledge collapsed under its own weight. The Professionals: Science becomes Specialized The Enlightenment also saw tremendous advances in every area of natural philosophy. The natural philosopher grew in social status, and Scientific societies such as the English Royal Society and the French Royal Academy became prestigious institutions with paid research staff. The sciences also began dividing from the blanket natural philosophy into the modern categories: physics, chemistry, astronomy, biology, etc. Along with specialization came specialists, experts who devoted themselves to advancing one area, and were often hired by the societies or universities based on their areas of expertise. Example in Life Science: Linnaeus Linnaeus ( ) Swedish Naturalist, developed the modern binomial (genus, species) method of taxonomical listing Promoted the modern taxonomical distinctions based upon reproductive organs in plants Adherent of natural theology the study of God through nature Using reason, all of nature could be turned to practical ends, according to Linnaeus. Advocated practical (?) revolutions in farming such as the domestication of reindeer as a food source, along with guinea pigs ( slaughtered, shaved, and fried ) and the replacement of horses with moose in Sweden. 3

4 Example in Chemistry: Lavoisier Father of Modern Chemistry Advanced work on a gas which he named oxygen. Experiments with combustion proved that burning is a process combining a substance with oxygen. Oxidation, likewise, combined a prior substance with this gas. Also demonstrated that respiration in plants and animals requires oxygen, and can be likened to combustion. Advanced the production of saltpeter and gunpowder, for the use of the state. Worked as a team with his wife, Marie-Anne. Although not a royalist, he was arrested, tried and guillotined by the Revolution on May 8, According to the judge: The Republic has no need of geniuses. Galvani v. Volta And the Frog Massacre Luigi Galvani ( ) Anatomist and physiologist, Academy of Sciences in Bologna Worked on comparative anatomy, and, beginning in the 1780 s, the effect of electricity (static charges) on animal tissue. 26 Sept While working on a fresh frog leg, Galvani observed it jump when a metal dissecting instrument was touching it and an electrical discharge occurred nearby. The experiment was repeatable, as long as the frog leg was fresh. An undisclosed number of frogs later, Galvani devised a new experiment which involved fastening frogs to an iron railing outside his house via brass hooks through the spinal cords of the frogs. The Iron Rail Experiment The frog bodies were hung on Galvani s fence during an electrical storm. Surprisingly, Galvani observed that the frog legs would jump not only when the lightning flashed but even at times when the sky was quiet and serene. More frogs were needed. Galvani repeated the experiment and observed that he could make the frogs jump by pressing the brass hooks against the iron railing. He concluded that all animal bodies might produce a native electric charge (like electric eels.) Galvani followed this with new experiments (and many more frogs.) He observed that nerves were more sensitive than other cells, and concluded that they were designed to carry electricity, that muscles are the receivers of this electricity, and that motion is the result of continual discharges of electricity by the brain. Galvani published his findings in Alessandro Volta ( ) Physics professor at Pavia, and a friend of Galvani. (Volta coined the term galvanism in honor of him.) Volta read Galvani s study and initially agreed with the findings, but he also sought out his own frogs, and repeated all of Galvani s experiments. Eventually, Volta began to focus on the metals and not the frogs. He discovered that two dissimilar metals in contact with moisture produced a charge. Volta countered that the frogs were unnecessary, it was the metals which produced electricity, and Galvani had misinterpreted the evidence. A good natured, but serious, debate ensued in which followers rallied to one opinion or the other. In 1794 Galvani and an assistant published a paper in which they had been able to produce the reaction without using metals at all, merely by using the frogs own nerves. This experiment was more difficult to reproduce, and many, including Volta himself and the Royal Society, believed that Galvani had been refuted. Volta makes a Pile The discovery of a charge resulting from the contact of two different metals set Volta off in a different direction of inquiry. Volta began arranging metals on a scale based upon the degree of the charge they produced when in contact with one another and moisture. He found the most significant results came from silver and zinc. By arranging disks of zink and silver with a paper soaked in saline solution in between, Volta found that the electric effect could be magnified. By setting up 30 such Voltaic Piles in connection with each other, sufficient electricity was produced to keep a continuous flow of electricity going to a person who had a hand in a bowl of water at each end of this array. By connecting bowls of water with wires that had different metals on the ends, Volta demonstrated that direct contact between the metals did not increase the effect (but a moist separator was necessary). 4

5 Conclusions As a result of specialization Galvani and Volta interpreted the reaction of the frog legs differently: Galvani, the anatomist, looked to the frog, and Volta, the physicist considered the metals. Both Galvani and Volta were partially right, though it would be more than a century before Galvani s observations would be justified and qualified by the development of the chemical-electrical theory of neural impulses. The debate, which began with the anatomy of frogs, brought physics to the threshold of the wet cell which was developed from Volta s theories by the Englishman William Cruikshank in From physics, the chain reaction of the voltaic pile in science led onward to chemistry -- in 1800 William Nicholson and Anthony Carlisle noticed a drop of water at one end of the pile giving off gas. In 1813, the chemist Humphrey Davey identified the gases, and the composition of water. In addition to rigorous method, the Galvani/Volta debate rested upon a series of fortuitous accidental discoveries, each of which led to more rigorous experimentation, and ultimately to advances in four different fields. 5