Aristotle’S Voluminous Writings Provide a Case Ages We ﬁnd That This Thread, Though Perilously in Point

9781405175432_4_001.qxd 1/12/2008 16:54 Page 3 Part I 9781405175432_4_001.qxd 1/12/2008 16:54 Page 4 9781405175432_4_001.qxd 1/12/2008 16:54 Page 5 Introduction to Part I 1 The Unbroken Thread largely reduced to anatomy and conjectural tax- onomy, and its connections to chemistry and The various scientific disciplines as we know them geology are severed. today have distinctive characteristics by which Even as far back as 1700, at least physics and even the uninitiated can recognize them. Physics astronomy look like threadbare versions of their has intricate equations and imposing particle modern selves. But when we retreat backwards accelerators, astronomy boasts orbital telescopes across the 1600 line, the fabric of science un- and maps of supergalactic clusters, biology has ravels with shocking abruptness. Physics is shorn a sweeping evolutionary narrative and describes of its mathematical tools, including calculus proteins that fold into exact three- dimensional and modern algebra, and the foundations of shapes to catalyze reactions, chemistry proudly elementary dynamics are in disarray. Telescopes displays its periodic table and produces number- and microscopes have disappeared. What passes less new compounds that find their way into the for chemistry is inseparable from alchemy, and surgical room and the supermarket. And the dis- astronomers eke out their incomes by casting ciplines are linked in important ways. Geology horoscopes for the nobility. The majority opinion intersects with both evolutionary biology and is that the earth does not orbit the sun or rotate physics. Physicists are as interested in the periodic on its axis, and fundamental biological facts such table as chemists. Biochemistry straddles the dis- as the circulation of the blood are unknown. ciplinary division between biology and chemistry. We might stop there and declare that, prior Astronomers make use of physics to describe to 1600, science simply did not exist. But on a exotic objects like black holes and to understand closer look this drastic pronouncement appears stellar evolution. too simplistic. Though the technology and even But as we work our way backwards in time, the fundamental principles of all the major the view becomes less and less familiar. Much sciences are absent, there remain recognizable of the technology that is the cultural signature similarities of aim and purpose. It is not just that of physics and chemistry disappears by the time we recognize, beneath the strange terminology we cross the 1900 line. When we move back of alchemy and surrounded by a good deal of to 1850, biology has lost its grand unifying nonsense, bits of true empirical lore; the more vision and chemistry has lost its table of the ele- significant fact is that the alchemists are actively ments. Prior to 1800 chemistry looks even less seeking a set of basic principles that govern familiar, with odd substances like phlogiston the transformations of matter. In astronomy, and caloric populating the textbooks. Biology is the models of the solar system are complex 9781405175432_4_001.qxd 1/12/2008 16:54 Page 6 6 introduction to part i geometrical nightmares; but the underlying aim 2 Greek Science and Greek Philosophy of giving a rational account of the motions of the sun, moon, planets, and stars remains. In The early history of science is largely a history anatomy the leading thinkers are investigating the of philosophical ideas regarding the nature and structure of the human body with great attention structure both of the cosmos and of our know- to detail, and in medicine the best minds are ledge of it. Philosophy and science flourished hunting for the causes of disease and the together in the golden age of Greece; indeed, mechanisms of contagion. In the aims of these the line between them was not as sharply drawn Renaissance disciplines, we can see a thread of con- as it is today, and in many cases it is difficult tinuity stretching from that era to our own. to say where philosophy ends and science begins. Moving carefully backwards through the Middle Aristotle’s voluminous writings provide a case Ages we find that this thread, though perilously in point. In founding the discipline of logic, thin, is never quite broken. We see it in Paris for example, Aristotle does more than to codify during the 1300s. It virtually disappears from the some principles of correct reasoning and list west prior to 1100 but remains visible in the some common fallacies; he fashions syllogistic work of Arab and Persian and Jewish scholars in logic with one eye on the metaphysics of essences Baghdad and Cordoba and Damascus and Fez. In and the other on the structure of scientific the 500s, it surfaces in Alexandria. Moving back knowledge. Scientific knowledge, according to before the fall of Rome we find it in Italy, and other Aristotle, is demonstrative: it is arrived at by threads appear across the Roman Empire. Before rigorous reasoning from premises that are them- the dawn of the Christian era these threads selves known and not merely conjectured. An stretch back into Greece, where for a brief and infinite regress threatens, each item of knowledge glorious period they draw together into a vivid requiring others to be known first. Aristotle sees conceptual ribbon woven in rich texture with and resolves this problem by developing a version strange but explicit designs. Back through Archi- of foundationalism, the view that all scientific medes and Euclid, Aristotle and Plato, Epicurus knowledge rests in the end on primary certain- and Democritus and Empedocles and Pythagoras ties that are known immediately rather than by and Thales we can trace it, though the ribbon derivation from anything else. narrows to a mere thread again at the earliest parts The analogy here with mathematics is very of this period. strong, and this is no accident. Aristotle wrote And there at last, somewhere around 600 BC, about one generation before Euclid, and geometry, the thread disappears altogether. already a well-developed branch of learning, This is why we must begin our study of the provided a compelling model of structured and history of science with the Greeks. They were the certain knowledge. But in the case of geometry, first thinkers known to us who clearly articulated the foundations are – most of them – intuitively the idea that the world is a cosmos, an ordered compelling. It is natural to ask whether the ana- whole governed by rationally discoverable prin- logy can be pressed at this point. Are there also ciples. The earliest conjectures regarding the intuitively compelling foundations for biology, nature of those principles look wholly foreign to astronomy, and the other sciences? If so, what are us, even absurd. Thales guessed that the funda- they? And by what means can we identify them? mental stuff out of which all things are made is Aristotle’s answer is suggestive but frustrat- water, Anaximander suggested that it was some- ingly inexplicit: in experience we recognize, some- thing formless and boundless, Anaximenes thought how, the universal implicit in a few particular it was air, and Xenophanes took it to be earth. instances. In one sense this is plausible enough. But their varied and incompatible answers are far We see many cats that differ in size and color and less interesting than the assumption lying behind shape of head, but they are all similar; later when the question they all seek to answer: the assump- we see another cat we can recognize that it is the tion that there is a fundamental kind of stuff and same type of creature. But does this experience that the bewildering complexity of the visible give us knowledge of the essence of felines – that world is in some way a function of a simpler is, of their true nature? And is that knowledge underlying order. certain, so that the conclusions we deduce from 9781405175432_4_001.qxd 1/12/2008 16:54 Page 7 introduction to part i 7 it will also be certainties? These are high standards. each epicycle rides on the circumference of a Aristotle is well aware that mere enumeration larger circle, with the earth standing motionless of instances does not guarantee knowledge of near the center of the whole system. The complete essences; the mental move he calls epagoge, in construction, which sometimes involves epicycles which the mind rises from perception of particu- upon epicycles and epicycles oriented vertically to lars to knowledge of universals, cannot be flattened account for latitudinal motions of the planets, is out into anything like induction in the modern enormously complex. It yields, however, reason- sense. For the next two millennia, some of the best ably accurate predictions for the visible motions minds in the world wrestled with the problems of all of the major heavenly bodies. posed by Aristotle’s account of the structure and But was the resulting construct real? Was this foundations of scientific knowledge. the way the heavens were constituted? Once A second strand of Greek thought about scien- asked, the question could not be retracted. If the tific knowledge is no less important: science aims goal of science is to give knowledge not just of to give us not merely foresight but understanding. the fact but of the reasoned fact, as Aristotle puts Predictive astronomy is older than the attempt it, then mere guesses at the hidden mechanism to understand why things happen in the heavens. of the universe could never suffice. In the long Babylonian cuneiform tablets bearing dated records history of commentary both on Aristotle and on of astronomical events reach as far back as 747 BC, Ptolemy there is much more than mere servile and star catalogues and records of planetary endorsement.

Load more