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Home , Consilience (book)

DESCARTES’ DREAM

A USED BOOK STORE I love to browse through used bookstores. Not surprisingly, some of the best ones happen to be in university towns. That is one of the perks of going to meetings of scientific societies because they are almost always held on large university campuses. About 10 years ago, a collection of ecological and organismal societies met on the campus of the University of Toronto. Certainly, Toronto is much more than a university town, but the city is made of many neighborhoods, each with its distinctive character. That is true, too, of the area around the university. Between talks and meetings I wandered the university neighborhood and went into a large used bookstore. The store was average in size, but its holdings were amazing. I recall that I missed a whole session of talks because I spent so much time browsing and talking to the store owner. Although there were several glass cases with books that appeared to be important, there was one case with some interesting and very old books. One book was covered with white velum and occupied a place of some importance. I asked if I could see the book, but the proprietor, with whom I had been talking about various old books, just smiled and handed me a pair of white cotton gloves. He unlocked the case and urged me to open it up and read the title. I caught my breath as I read Discours de la Methode (Discourse on the Method) . The book was from the mid seventeenth century and was written by Rene Descartes.

AN ETERNAL STUDENT There is need of a method for finding out the truth. –Rene Descartes Rene Descartes was born on March 31, 1596 to an aristocratic family in France. His father was a counselor of the Parliament of Brittany. On his mother’s side he appeared to have been descended from a long line of physicians. His parents sent him to the Jesuit school of La Fleche in 1606. until he left in 1614. He was supposed to have been sickly as a child and even the Jesuits allowed him to sleep until noon while there, a habit that he retained through his life. After La Flesche, Descartes spent the next two years in Paris studying . He then left Paris in 1617 to study law in Poitiers. Some authorities say that he received a law degree from Poitiers; however, that appears unlikely because he left within a year and never claimed to have a degree in law. Furthermore, because he was an aristocrat, and had enough money to support himself, he did not have to worry about how to make a living. Consequently, he had no need of a degree or a profession. Descartes became a volunteer without pay in the Dutch army of the Prince of Orange in whose service he wandered over much of Europe. He finally settled in the Netherlands in 1628. While there, he attended universities at Franeker (1629) and Leyden (1630). Again, he seemed to have been attracted to universities for the sake of learning, not to obtain a degree. Descartes was not an extravagant man, but he lived comfortably by a pension that he received from his father. Later, he inherited money from his mother’s and father’s estates, which allowed him the freedom to live as he chose. How is it, then, that a man who was without ambition became a household name in Europe? In 1628, Descartes met with Cardinal Berulle who implored the young aristocrat to

1 use his talents. In fact he stressed that God would hold Descartes accountable for how he employed his abilities. Berulle’s admonition seemed to light a fire in Descartes, who showed a burst of productive work that lasted from 1629 to 1649. During that time he lived in Holland, but although he remained in the same country, he did not like to live in the same place and moved about twenty times during that twenty-year period. Always he required that he live in the neighborhood of a university and a Catholic Church, both of which were sources of inspiration. Much earlier, Descartes claimed to have had a series of dreams in which the method for discovering fundamental laws governing nature were revealed by “the Spirit of Truth”. He “experimented with this method and the application of mathematics to questions in physics.

LAWS AND EXPLANATION ...To divide up each of the difficulties which I examined into as many parts as possible, as seemed requisite in order that it might be resolved in the best manner possible. –Rene Descartes Descartes’ method included several steps. The first of which was to reject everything so that the observer would be objective and without prejudice. The second step was to divide up the problem into as many parts as possible. In this way, the problem could be reduced to simpler and simpler components. This reduction or simplification of the problem is really an attempt to explain the problem. Descartes and his contemporaries were concerned with large problems like why do the planets stay where they do. That is, why do they seem to move around the sun (he agreed with Galileo on this) and not fall to the sun or fly away out of orbit. Later, formulated a mathematical statement, which he called the law of gravity that described the movement of the planets. In this law, Newton said that it made no difference whether the object was a planet or an apple, two bodies attract each other according to the product of their masses and the inverse square of their distance from each other. This law describes the behavior of orbiting planets, falling apples, and any objects of mass. Nevertheless, Newton’s law of gravity does not define gravity itself. The other laws of and physics behave the same way. For example, Boyle’s Law describes the relationships between the pressure, temperature, and volume of a gas. It does not explain what pressure and temperature are, but describes their relationships with mathematical precision. Chemistry and physics are generally referred to as the physical . Laws within these sciences are universal and ultimately, all phenomena in nature must reduce to one or more of the physical laws. Some claim that this is the way in which phenomena are explained, by reducing them to natural laws. In essence, this is the second step of Descartes’ method. That is, the phenomenon should be reduced to descriptive laws and, thereby, be explained.

AN INVERTED PYRAMID ...To separate out what is quite simple from what is complex. –Rene Descartes The science of Descartes was mainly that of optics and mechanics. His book Discourse was written around the birth of Newton (and the death of Galileo), and Descartes,

2 himself, died before the publication of Newton’s Principia. Nevertheless, he recognized that the physical sciences were necessarily the simpler or less complex of the sciences. Other sciences like and Geology are more complex than Chemistry and Physics. The more complex sciences are more defined by complex interactions of their constituent parts. For the sake of explanation, the landforms around my home in Freeburg, PA can be reduced to the actions of erosion, sedimentation, plate tectonics, geochemistry, climate, and hydrology. Those can be reduced to aspects of chemistry and physics. Although they are reducible to the laws of chemistry and physics, those laws do not indicate the particular interrelationships that gave rise to Pleasant Valley. That would have to be given in a narrative style more like that of a historian than a physicist although the story must not violate physical law. Thus, I view the sciences as an inverted pyramid (see Figure 1) with the less complex and more abstract disciplines at the bottom. Above chemistry and physics rise geology and biology. These are crowned by the most complex of the sciences, namely Environmental Science and Psychology.

FIGURE 1. The hierarchy of explanation in the sciences. Sciences at the top are the more complex. Ultimately, all sciences reduce to the laws of the physical sciences (divided from the complex sciences by the horizontal bar). Physics is described by mathematics.

3 Because the complex sciences depend upon interrelationships that might be unique, they cannot generate their own universal laws. For example, there can be no universal laws of life because life as we know it is unique to planet earth. I have no doubt that if life is found elsewhere, it would be so different in its details that we would have some difficulty even recognizing that it is life.

WHAT? HOW? WHY? It is true as regards the which may conduce to this end, that one man could not possibly accomplish all of them. –Rene Descartes Biology, like the sciences as a whole, displays a nested or hierarchical form. As I look out of the window in my study, I see a forested ridge. The forest community is made up of a collection of species each represented by its own collection or population. The population is made up of individuals, each of which (in the case of the plants, animals and fungi) is constructed of organs that are made of tissues composed of cells. All of these have their own anatomies and physiologies defined by their particular molecular biologies. Another way to say it is that the study of life ranges in complexity from molecular biology (the simplest) to (the most complex). The simpler the science, the more easily it lends itself to the experimental method. Experimentation requires, above all, that the system in question be simple or simplified. Suppose, for example, that you are interested in the nutritional requirements of the common yeast (Saccharomyces cerevisiae). In particular, does it grow best on a simple sugar like glucose or a more complex sugar like sucrose (also known as table sugar, sucrose is a disaccharide made of glucose and fructose). Immediately, I imagine an in which equal concentrations of yeast are measured into flasks. Half of the flasks are given sucrose and the other half are given glucose in equal concentrations. Growth response could be measured by the rate at which yeast cells divide by determining the change in cell concentration over hours or days. However, an easier way would be to measure the volume of carbon dioxide given off by the over time. Everything but the form of sugar must be constant in order to make this comparison. A more complex question would be to explore dietary requirements in humans. Researchers cannot put their human subjects into flasks or restrict diets sufficiently to look for deficiencies in vitamin C and incipient scurvy. Ernst Mayr, evolutionary biologist and philosopher of biology, said that questions asked by biologists tend to fall into “What?”, “How”, and “Why” categories. Answers to what questions tend to be descriptive and provide a factual basis for the discipline. Unfortunately, to say that a discipline is descriptive is almost pejorative in biology. Certainly, description is the first step of any discipline. It should not be surprising, then, that much of molecular biology has been descriptive. The studies of taxonomy and biological diversity remain descriptive. “How?” questions according to Mayr are most frequently asked in functional biology from molecular biology through physiology and development. Answers to “How?” questions tend to be answers to experiment and, therefore, are quite powerful in their ability to explain. Not surprisingly, “How?” questions are the most frequently asked questions in the physical sciences. “Why?” questions are asked in relation to evolutionary connections between organisms or between organisms and their environment. Mayr points out that made “Why?” questions legitimate in biology after publication of the Origin of

4 Species in 1859. Theodosius Dobzhonsky went even farther and said ”nothing in biology makes sense except in light of .” That is, because all living things share a common descent, life on earth bears certain fundamental similarities. These are now being explored at all levels in biology.

HISTORICAL SCIENCE ...To carry on my reflections in due order, commencing with objects that were the most simple and easy to understand, in order to rise little by little, or by degrees, to knowledge of the most complex, assuming an order, even if a fictitious one among those which do not follow a natural sequence relatively to one another. –Rene Descartes Descartes’ third step was to reconstruct the parts of the phenomenon. That is, to take the simpler components and build more complex scenarios. This is known as prediction and is the second important function of science. Prediction begins with theories and natural laws and attempts to define particular outcomes. Experiments are special cases in which hypotheses (predictions) are tested by holding most variables constant. In this way predictions can be pronounced false or confirmed. Experiments are not the only methods to be employed in predicting nature. As the scientist explores questions of greater and greater complexity, it becomes more and more difficult to hold variables constant. By and large, ecologists face this difficulty. Interactions in a grassland or flowing stream are almost infinitely more complex than interactions within a flask of yeast. In general, ecology occurs as two different types of subdisciplines: ecology of the species and ecology of communities. Ecology of the species is called autecology and usually is practiced by zoologists (animal biologists). A group of individuals in the same species that occupies the same area is called a population and most autecology deals with populations. Particular questions would deal with competition (either within a population or between populations), densities (reproduction and population size), predator-prey relationships, food chains, and life cycles. Botanists (those who study the myriad of organisms that are not animals) tend to study communities or synecology. A community is the collection of populations and their interrelationships in a particular area. Questions asked by synecology includes succession (changes in communities), climax (stable communities), ecosystems (the movement of materials and energy through a community), and biodiversity. I have explored questions that are both autecological and synecological in nature. In all cases, I tried to discover the dominant influences over populations or communities because it was impossible to discover all of the controlling factors. Indeed, the interactions generally are the objects of study. Aspects of history also play a large part in ecology. That is, a community exists in time as well as in space. The conditions that affect a community were influenced by the conditions that preceded them. My stream studies are strongly affected by time of year, storm events, farming practices, as well as by the biota that occurred there the preceding week or day. My students get tired of hearing me say that ecology is historical. If I failed to collect samples correctly on September 3, 1998, I would not be able to go back in time to collect them. In that sense, all ecological data are unique and ecologists are more like historians in their reconstructions except that nature does not leave records that are easily read.

5 FALSE PATTERNS It must always be recollected, however, that possibly I deceive myself and what I take to be gold and diamonds is perhaps no more than copper and glass. –Rene Descartes Because explanations and predictions in ecology are the products of the history of a particular population or community, patterns may appear when they do not exist. Take a very simple case. Last spring I conducted a “random walk” test in which I tossed a nickel 200 times. Prior to the “experiment”, I decided that heads would have the value of +1 and tails the value of –1. The first toss was tails (-1), the second toss was heads (+1). These were independent events, each with a 50% chance of happening. However, I made them dependent such that the value of toss two equaled the sum of heads and tails (-1+1=0). Toss 200 was equal to the sum of all heads and tails. I plotted the number of the coin toss against the sum value (By the way, the graph with its X-Y coordinates was an invention of Descartes’ to allow algebra to be visualized. That is why this system is called Cartesian coordinates.). Figure 2 clearly shows the rise and fall that could be a pattern. It is not. This is the consequence of each point being dependent on those that preceded it. To put it another way, each point is a product of its history and subject to the contingencies of that history. For example, tosses 85 to 91 were all tails. That caused the line to plunge. However, each toss had a 50-50 chance of being heads or tails. I was concerned that the graph represented an unequal distribution of heads and counted the number of heads and tails. To my surprise, I had 98 tails and 102 heads in a random pattern.

FIGURE 2. A random walk illustrating a false pattern.

6 I keep that graph on my wall in the office as a warning, a warning that was so eloquently stated by Simon and Garfunkel when they sang, “A man hears what he wants to hear and disregards the rest.” If pseudopatterns can be created by the history of a coin toss, imagine the problems facing ecologists.

PLEISTOCENE PARK And I thought that it was easy for me to select certain matters which would not be the occasion for many controversies. –Rene Descartes Aside from my own research, which holds the most interesting problems for me, ecology is filled fascinating problems, both large and small. One of the most interesting problems in ecology is discussed in the October 2, 1998 issue of Science. A Russian scientist, Sergei Zimov, is convinced that he can recreate a Mammoth Steppe, a cold grassland that occurred at the leading edge of the glaciers during the last ice age. The problem is greater than just making a parkland. He believes that he can regenerate a whole ecosystem. Zimov and teams of scientists from Canada and Alaska think that the Mammoth Steppe grasslands were shaped by the actions of mammoths, bison and other large herbivores, themselves. That is, the constant disturbance provided by the animals destroyed the mosses and favored the growth of grasses. Zimov plans to change an area in northern Siberia (above the Arctic Circle) that is dominated by mosses by reintroducing bison, horses, and musk oxen. His computer models suggest that the disturbance provided by the animals will destroy the mosses that grow there and allow for the revival of a cold grassland. He is even considering the introduction of Indian Elephants (What he will do with them during the long, Arctic winters I don’t know). Zimov’s idea has not been met by universal enthusiasm by the scientific community. Some object that the mosses occur in Northern Siberia because the climate is much wetter now than it was during the Pleistocene. Also, there is that particularly difficult problem of a Mammoth Steppe without a mammoth. Zimov counters that the climate now probably is as moist as it was 11,000 years ago. Although there is evidence that Pleistocene-age soil was much drier than now, grasses, were much better at pulling water from the ground than were mosses. If he is successful in his attempt to establish large numbers of herbivores, he will have to add carnivores to make it a stable ecosystem. To that end, he has plans to add wolves and Siberian tigers. Suppose that Zimov is successful. Suppose that he can establish large herds of horses (there now), the wood bison (coming from Canada) and other herbivores and carnivores. Suppose that the populations become stable, tear up the moss-dominated landscape, and grasses begin to take over. Would this prove that mammoths created the Mammoth Steppe? No, it would not. However, it would confirm that such control is possible. This project is particularly interesting to me because it explores typical synecological problems. However, the project also attempts to reconstruct the autoecology of the extinct Woolly Mammoth. The project will last many years with a great likelihood of uncertain results. This is the predicament of complex science.

7 A PLEA FOR ...Long chains of reasoning..., simple and easy as they are,... had caused me to imagine that all those things which fall under the cognizance of man might very likely be mutually related in the same fashion. –Rene Descartes Still, as difficult as it is to glean knowledge from nature, we have been quite successful. Science has advanced our understanding of the natural universe from the Renaissance to the present. E. O. Wilson attributes most of the success of the sciences to the vertical relationship in explanation from the simple to the complex sciences. The vertical association of the disciplines in sciences means that they have a common foundation of natural law. Wilson suggests in his book Consilience (a word that means jumping together) that the other disciplines could be brought into a similar vertical relationship with science at their base. He suggests that Psychology could serve as the foundation of the Social Sciences. Thus, the Social Sciences would have to be consistent with the “laws of psychology”. Similarly, the Social Sciences would serve as the basis for the Humanities which would serve as the basis for the . Descartes, himself, was interested in many areas of knowledge. He was the founder of modern , a physicist, and mathematician. He wrote on topics that ranged from embryology and medicine to music. He indicated that his methods were meant for a consilience-type of understanding. In 1633 Descartes was nearing the completion of a monumental work called a Treatise on the World. This was a major work that attempted to integrate all knowledge. He abandoned its publication when he saw the treatment of Galileo by the Catholic Church. His next work was Discourse on the Method. Still, Descartes and his philosophy were controversial. Even in liberal Holland his works were viewed with suspicion by the church and civil authorities and he was protected by influential people like Princess Elizabeth, daughter of Frederick V who was in exile in Holland. One lasting effect that he had on science was an insistence that there was a fundamental difference between mind and body. In many ways, this has been one of the greatest barriers to the consilience of Psychology with the rest of the sciences. In 1649 Descartes was enticed to go to Sweden in the service of Queen Christina. He was to teach philosophy to her and set up an academy of science. Unfortunately, within a year, Descartes contracted pneumonia and died on February 11, 1650.

THE FOURTH ADMONITION ...I have since that time found other reasons which caused me to change my opinion. –Rene Descartes In the end, I decided not to buy the copy of Discourse on the Method. Although I was sorely tempted, the book cost about as much as I could muster at the time. I still had to get home and eat for the rest of the month. The experience did cause me to seek out a copy of Discourse when I returned home. I read the somewhat stilted translation and was impressed by how clearly he described the practice of science. The fourth step of Descartes’ method was to repeat steps one through three to confirm the results. It is possible to repeat those steps in the simple sciences by description (answers to “What?” questions) and experiment (answers to “How?” questions). However, like

8 Descartes’ life, Zimov’s Pleistocene Park, and my studies in aquatic ecology, it is impossible to repeat the steps in a historical science. -Jack Holt, December 1998 BIBLIOGRAPHY: Bowler. Peter J. 1992. The Fontana History of the Environmental Sciences. Fontana Press. London. Carnap, Rudolph. 1966. The Value of Laws: Explanation and Prediction. In: Martin Curd and J.A. Cover, eds. 1998. , The Central Issues. W.W. Norton and Co. New York. Descartes, Rene. 1629. Rules for the Direction of the Mind. Trans. Elizabeth Haldane and G.R.T. Ross. In: Robert M. Hutchins, ed. 1952. The Great Books of the Western World. Vol 31. Encyclopaedia Britannica, Inc. Chicago. Descartes, Rene. 1637. Discourse on the Method. Trans. Elizabeth Haldane and G.R.T. Ross. In: Robert M. Hutchins, ed. 1952. The Great Books of the Western World. Vol 31. Encyclopaedia Britannica, Inc. Chicago. Hempel, Carl G. 1962. Two Basic Types of Scientific Explanation. In: Martin Curd and J.A. Cover, eds. 1998. Philosophy of Science, The Central Issues. W.W. Norton and Co. New York. Hull, David L. 1988. Science as a Process. University of Chicago Press. Chicago. Mayr, Ernst. 1982. The Growth of Biological Thought: Diversity, Evolution, and Inheritance. The Belknap Press of the Harvard University Press. Cambridge, Mass. Mayr, Ernst. 1997. This is Biology, The Science of the Living World. The Belknap Press of the Harvard University Press. Cambridge, Mass. Nagel, Ernest. 1961. The Structure of Science, Problems in the Logic of Scientific Explanation. Harcourt, Brace and World, Inc. New York. Nagel, Ernest. 1974. Issues in the Logic of Reductive Explanations. In: Martin Curd and J.A. Cover, eds. 1998. Philosophy of Science, The Central Issues. W.W. Norton and Co. New York. Rosenberg, Alexander. 1986. The Structure of Biological Science. Cambridge University Press. New York. Stone, Richard. 1998. A bold plan to re-create a long-lost Siberian ecosystem: an international team of scientists will test whether bison, horses, and other large grazers can bring back the mammoth steppe. Science. 282(5386): 31-33. Wilson, Edward O. 1998. Consilience, The Unity of Knowledge. Alfred A. Knopf. New York.

Internet Sources: http://es.rice.edu/ES/humsoc/Galileo/Catalog/Files/descartes.html http://www.brooklyn.cuny.edu/bc/ahp/SDPS/SD.PS.Outline.html http://www.nrm.se/virtexhi/mammsaga/ecosyst.html http://www.utm.edu/research/iep/h/hempel.htm http://www2.lucidcafe.com/library/96mar/descartes.html http://www2.theatlantic.com/atlantic/unbound/bookauth/ba98031.htm

9 QUESTIONS TO THINK ABOUT

1. What likely pushed Rene Descartes to be productive in mathematics, science, and philosophy?

2. What is the nature or characteristic of natural law?

3. What is Descartes’ method?

4. What do I mean by the simple sciences and the complex sciences?

5. How does the inverted pyramid (Figure 1) illustrate the hierarchy of explanation in the sciences?

6. What are the three kinds of questions asked in the sciences?

7. How does a historical science differ from an experimental science?

8. Why did I refer to Figure 2 as illustrating a false pattern?

9. What is the goal of Sergei Zimov?

10. What does consilience mean?

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