- History of science in Classical Antiquity
The history of science in Classical Antiquity begins with the search for practical knowledge. In Antiquity, the inquiry into the workings of the universe took place both in investigations aimed at such practical goals as establishing a reliable calendar or determining how to cure a variety of illnesses and in those abstract investigations known as
natural philosophy. The ancient peoples who are considered the first " scientists" may have thought of themselves as natural philosophers, as practitioners of a skilled profession (for example, physicians), or as followers of a religious tradition (for example, temple healers).
The practical concerns of the ancient Greeks to establish a calendar is first exemplified by the "Works and Days" of the Greek poet
Hesiod, who lived around 700 BC. The "Works and Days" incorporated a calendar, in which the farmer was to regulate seasonal activitities by the seasonal appearances and disappearances of the stars, as well as by the phases of the Moon which were held to be propitious or ominous. [Lloyd (1970), p. 81; Thurston, p. 21.] Around 450 BC we begin to see compilations of the seasonal appearances and disappearances of the stars in texts known as "parapegmata", which were used to regulate the civil calendars of the Greek city-states on the basis of astronomical observations. [Thurston, pp. 111-12; D. R. Lehoux, "Parapegmata: or Astrology, Weather, and Calendars in the Ancient World", [http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ53766.pdf PhD Dissertation, University of Toronto, 2000] , p. 61.]
Medicine provides another example of practically oriented investigation of nature among the Ancient Greeks. It has been pointed out that Greek medicine was not the province of a single trained profession and there was no accepted method of qualification of licensing. Physicians in the Hippocratic tradition, temple healers associated with the cult of Asclepius, herb collectors, drug sellers, midwives, and gymnastic trainers all claimed to be qualified as healers in specific contexts and competed actively for patients. [Lloyd (1979), pp. 38-9.] This rivalry among these competing traditions contributed to an active public debate about the causes and proper treatment of disease, and about the general methodological approaches of their rivals. In the Hippocratic text, "On the Sacred Disease", which deals with the nature of epilepsy, the author attacks his rivals (temple healers) for their ignorance and for their love of gain. The author of this text seems modern and progressive when he insists that epilepsy has a natural cause, yet when he comes to explain what that cause is and what the proper treatment would be, his explanation is as short on specific evidence and his treatment as vague as that of his rivals. [Lloyd (1979), pp. 15-24.]
There were several acute observers of natural phenomena, especially
Aristotleand Theophrastus, who wrote extensively on animals and plants. Theophratus also produced the first systematic attempt to classify minerals and rocks, summarised in the Naturalis Historiaof Pliny the Elderin 77 AD.
This pattern of debate is found among the earliest Greek philosophers, known as the
pre-Socratics, who provided alternative answers to the same question found in the myths of their neighbors: "How did the ordered cosmosin which we live come to be?" [Cornford, p. 159.] But although the question is much the same, their answers and their attitude towards the answers is markedly different. As reported by such later writers as Aristotle, their explanations tended to center on the material source of things. Thalesof Miletus (624-546 BC) considered that all things came to be from and find their sustenance in water. Anaximander(610-546 BC) then suggested that things could not come from a specific substance like water, but rather from something he called the "boundless." Exactly what he meant is uncertain but it has been suggested that it was boundless in its quantity, so that creation would not fail; in its qualities, so that it would not be overpowered by its contrary; in time, as it has no beginning or end; and in space, as it encompasses all things. [Lloyd (1970), pp. 16-21; Cornford, pp. 171-8.] Anaximenes (585-525 BC) returned to a concrete material substance, air, which could be altered by rarefaction and condensation. He adduced common observations (the wine stealer) to demonstrate that air was a substance and a simple experiment (breathing on one's hand) to show that it could be altered by rarefaction and condensation. [Lloyd (1970), pp. 21-3.] Heraclitusof Ephesus (about 535 - 475 BC), then maintained that change, rather than any substance was fundamental, although the element fire seemed to play a central role in this process. [Lloyd (1970), pp. 36-7.] Finally, Empedoclesof Acragas (490-430 BC), seems to have combined the views of his predecessors, asserting that there are four elements (Earth, Water, Air and Fire) which produce change by mixing and separating under the influence of two opposing "forces" that he calls Love and Strife. [Lloyd (1970), pp. 39-43.]
All these theories imply that matter is a continuous substance. Two Greek philosophers,
Leucippus(first half of the fifth century BC) and Democritusof Abdera (lived about 410 BC) came up with the notion that there were two real entities: atoms, which were small indivisible particles of matter, and the void, which was the empty space in which matter was located. [Lloyd (1970), pp. 45-9.] Although all the explanations from Thales to Democritus involve matter, what is more important is the fact that these rival explanations suggest an ongoing process of debate in which alternate theories were put forth and criticized.
The materialist explanations of the origins of the cosmos seems to miss an important point. It doesn't make much sense to think that an ordered universe comes out of a random collection of matter. How can a random assemblage of fire or water produce an ordered universe without the existence of some ordering principle?
The first step in this emphasis upon a model was that of the followers of
Pythagoras(approximately 582 – 507 BC), who saw number as the fundamental unchanging entity underlying all the structure of the universe. For Pythagoras and his followers matter was made up of ordered arrangements of point/atoms, arranged according to geometrical principles into triangles, squares, rectangles, and the like. Even on a larger scale, the parts of the universe were arranged on the principles of a musical scale and a number. For example, the Pythagoreansheld that there were ten heavenly bodies because ten is a perfect number, the sum of 1 + 2 + 3 + 4. Thus with the Pythagoreans we find number emerging as the rational basis for an orderly universe — as the first proposal for a scientific ordering principle of the cosmos. [Lloyd (1970), pp. 24-31.]
Plato and Aristotle (Socratic Philosphers
Like the Pythagoreans,
Plato(c. 427–c. 347 BC) found the ordering principle of the universe in mathematics, specifically in geometry. A later account has it that Plato had inscribed at the entrance to his school, the Academy, "Let no man ignorant of geometry enter." [A. M. Alioto, "A History of Western Science", (Englewood Cliffs, NJ: Prentice-Hall, 1987), p. 44.] The story is a myth, but like all myths it has a grain of truth, for in his writings Plato repeatedly tell us of the importance of geometry.
Plato is known more for his contributions to the philosophical basis of scientific method than to particular scientific concepts. He maintained that all things in the material world are imperfect reflections of eternal unchanging ideas, just as all mathematical diagrams are reflections of eternal unchanging mathematical truths. Since Plato believed that material things had an inferior kind of reality, he considered that we don't achieve demonstrative knowledge – that kind of knowledge we call science — by looking at the imperfect material world. Truth is to be found through rational demonstrations, analogous to the demonstrations of geometry. [Lindberg, pp. 35-9; Lloyd (1970), pp. 71-2, 79.] Applying this concept, Plato recommended that astronomy be studied in terms of geometrical models [Plato, "Republic", 530b-c.] and proposed that the elements were particles constructed on a geometrical basis. [Plato, "Timaeus", 28b - 29a.]
Aristotle (384 - 322 BC) disagreed with his teacher, Plato, in several important respects. While Aristotle agreed with Plato that truth must be eternal and unchanging, he maintained that we come to know the truth through the external world which we perceive with our senses. For Aristotle, directly observable things are real; ideas (or as he called them, forms) only exist as they express themselves in matter or in the mind of an observer or artisan. [Lindberg, pp. 47-68; Lloyd (1970), pp. 99-124.]
This theory of reality led to a radically different approach to science:
* First, Aristotle emphasized observation of the material entities which embody the forms.
* Second, he played down the importance of mathematics.
* Third, he emphasized the process of change where Plato had emphasized eternal unchanging ideas.
* Fourth, he reduced the importance of Plato's ideas to one of four causal factors.
As this last point suggests, Aristotle's concept of causes was less limited than ours. Among causes he included:
* the matter of which a thing was made (the material cause).
* the form into which it was made (the formal cause; something similar to Plato's ideas).
* the agent who made the thing (the moving or efficient cause).
* the purpose for which the thing was made (the final cause).
Aristotle's emphasis upon causes fundamentally shaped the later development of science by insisting that scientific knowledge, what the Greeks called "episteme" and the Romans "scientia", is knowledge of necessary causes. He and his followers would not accept mere description or prediction as science. In view of this disagreement with Plato, Aristotle established his own school, the Lyceum, which further developed and transmitted his approach to the investigation of nature.
Most characteristic of Aristotle's causes is his final cause, the purpose for which a thing is made. He came to this insight through his biological researches, in which he noted that the organs of animals serve a particular function.:The absence of chance and the serving of ends are found in the works of nature especially. And the end for the sake of which a thing has been constructed or has come to be belongs to what is beautiful. [Aristotle, "De partibus animalium", 645a22-6; quoted in Lloyd (1968), p. 70.]
Thus Aristotle was one of the most prolific natural philosophers of Antiquity. He made countless observations of nature, especially of the structure and habits of
plants and animals. He also made many observations about the large-scale workings of the universe, which led to his development of a comprehensive theory of physics. For example, he developed a version of the classical theory of the elements (earth, water, fire, air, and aether). In his theory, the light elements (fire and air) have a natural tendency to move away from the center of the universe while the heavy elements (earth and water) have a natural tendency to move toward the center of the universe, thereby forming a spherical earth. Since the celestial bodies - that is, the planets and stars - were seen to move in circles, he concluded that they must be made of a fifth element, which he called Aether. [Lloyd (1968), pp. 134-9, 162-70.]
Aristotle could point to the falling stone, rising flames, or pouring water to illustrate his theory. His laws of motion emphasized the common observation that
frictionwas an omnipresent phenomenon - that any body in motion would, unless acted upon, "come to rest". He also proposed that heavier objects fall faster, and that voids were impossible.
His successor at the
Lyceumwas Theophrastus, who wrote valuable books describing plant and animal life. His works are regarded as the first to put botanyand zoologyon a systematic footing. He also produced one of the very first works on mineralogy, with descriptions of ores and minerals known to the world at that time. He made some shrewd observations of their properties. For example, he made the first known reference to the phenomenon of pyroelectricity, noting that the mineral tourmalinebecomes charged when heated. Pliny the Eldermakes clear references to his use of the work in his Naturalis Historiaof 77 AD, while updating and making much new information available on mineralshimself. From both these early texts was to emerge the science of mineralogy, and ultimately geology. Both authors describe the sources of the minerals they discuss in the various mines exploited in their time, so their works should be regarded not just as early scientific texts, but also important for the history of engineeringand the history of technology. Pliny is especially significant because he provides full bibliographic details of the earlier authors and their works he uses and consults. Because his encyclopediasurvived the Dark Ages, we know of these lost works, even if the texts themselves have disappeared. The book was one of the first to be printed in 1489, and became a standard reference work for Renaissancescholars, as well as an inspiration for the development of a scientific and rational approach to the world.
The important legacy of this period of Greek science included substantial advances in factual knowledge, especially in anatomy, zoology, botany, mineralogy and astronomy; an awareness of the importance of certain scientific problems, especially those related to the problem of change and its causes; and a recognition of the methodological importance of applying mathematics to natural phenomena and of undertaking empirical research. [Lloyd (1970), pp. 144-6.]
The military campaigns of
Alexander the Greatspread Greek thought to Egypt, Asia Minor, Persia, up to the Indus River. The resulting Hellenistic civilizationproduced seats of learning in Alexandriain Egypt and Antiochin Anatolia along with Greek speaking populations across several monarchies. Hellenistic science differed from Greek science in at least two ways: first, it benefited from the cross-fertilization of Greek ideas with those that had developed in the larger Hellenistic world, secondly, to some extent it was supported by royal patrons in the kingdoms founded by Alexander's successors. Especially important to Hellenistic science was the city of Alexandria in Egypt, which became a major center of scientific research in the third century BC. Two institutions established there during the reigns of Ptolemy I Soter(reigned 323 - 283 BC) and Ptolemy II Philadelphus(reigned 281 - 246 BC) were the Library and the Museum. Unlike Plato's Academy and Aristotle's Lyceum, these institutions were officially supported by the Ptolemies; although the extent of patronage could be precarious, depending on the policies of the current ruler. [Lloyd (1973), pp. 1-7.]
Hellenistic scholars frequently employed the principles developed in earlier Greek thought: the application of mathematics and deliberate empirical research, in their scientific investigations. [Lloyd (1973), p. 177.]
medicine, Herophilos(335 - 280 BC) was the first to base his conclusions on dissection of the human body and to describe the nervous system.
Geometers such as
Archimedes(ca. 287 BC – 212 BC), Apollonius of Perga(ca. 262 BC – ca. 190 BC) , and Euclid(ca. 325 BC – 265 BC), whose "Elements" became the most important textbook in mathematicsuntil the 19th century, built upon the work of the Hellenic era Pythagoreans. Eratosthenesused his knowledge of geometry to measure the distance between the Sunand the Earthalong with the size of the Earth.
Hipparchus(ca. 190 – ca. 120 BC) built upon the measurements of the Babylonian astronomers before him, to measure the precessionof the Earth. Pliny reports that Hipparchus produced the first systematic star catalog after he observed a new star (it is uncertain whether this was a novaor a comet) and wished to preserve astronomical record of the stars, so that other new stars could be discovered. [Otto Neugebauer, "A History of Ancient Mathematical Astronomy", (New York: Springer, 1975), pp. 284-5; Lloyd (1973), pp. 69-71.] It has recently been claimed that a celestial globe based on Hipparchus's star catalog sits atop the broad shoulders of a large second-century Roman statue known as the Farnese Atlas. [Bradley E. Schaefer, "The Epoch of the Constellations on the Farnese Atlas and Their Origin in Hipparchus's Lost Catalogue," "Journal for the History of Astronomy", 36(2005): 167-96. But see also Dennis W. Duke, "Analysis of the Farnese Globe," "Journal for the History of Astronomy", 37(2006): 87-100]
The level of Hellenistic achievement in
astronomyand engineeringis impressively shown by the Antikythera mechanism(150-100 BC). It is a 37-gear mechanical computer which computed the motions of the Sun and Moon, including lunar and solar eclipses predicted on the basis of astronomical periods believed to have been learned from the Babylonians. [cite journal | last = Freeth | first = T. |coauthors= "et al." | year = 2006 | title = Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism | journal = Nature | issue = 444 | pages = pp. 587–91 | doi = 10.1038/nature05357 | volume = 444 ; cite journal | last = Marchant | first = Jo | year = 2006 | title = In Search of Lost Time | journal = Nature | issue = 444 | pages = pp. 534–8 | doi = 10.1038/444534a | volume = 444 ; ] Devices of this sort are not found again until the tenth century, when a simpler eight-geared luni-solar calculator incorporated into an astrolabewas described by the Persian scholar, Al-Biruni. [cite journal | last = Charette | first = François | year = 2006 | title = High tech from Ancient Greece | journal = Nature | issue = 444 | pages = pp. 551–2 | doi = 10.1038/444551a | volume = 444 ; cite web | last = Noble Wilford | first = John | title = Early Astronomical ‘Computer’ Found to Be Technically Complex | work = The New York Times | date = 2006-11-30| url = http://www.nytimes.com/2006/11/30/science/30compute.html?ex=1322542800&en=088bd939ca75fbbb&ei=5088&partner=rssnyt&emc=rss | accessdate = 2006-11-30 ]
The interpretation of Hellenistic science varies widely. At one extreme is the view of the English classical scholar, Cornford, who believed that "all the most important and original work was done in the three centures from 600 to 300 BC" [F. M. Cornford, "The Unwritten Philosophy and Other Essays", p. 83, quoted in Lloyd (1973), p. 154.] At the other is the view of the Italian physicist and mathematician,
Lucio Russo, who claims that scientific method was actually born in the 3rd century BC, to be forgotten during the Roman period and only revived in the Renaissance. [cite book |last=Russo |first=Lucio |authorlink=Lucio Russo |title=The Forgotten Revolution: How Science Was Born in 300 BC and Why It Had To Be Reborn |year=2004 |publisher=Springer |id=ISBN 3-540-20396-6 |location=Berlin But see the critical reviews by Mott Greene, "Nature", vol 430, no. 7000 (5 Aug 2004):614 [http://www.nature.com/nature/journal/v430/n7000/full/430614a.html] and Michael Rowan-Robinson, "Physics World", vol. 17, no. 4 (April 2004) [http://physicsweb.org/articles/review/17/4/1/1] .]
Science in the
Roman Empireperiod was concerned with systematizing knowledge gained in the preceding Hellenistic period and the knowledge from the vast areas the Romans had conquered. It was largely their work that would be passed on to later civilizations. Of especial importance is the Naturalis Historiaof Pliny the Elderpublished in 77 AD, one of the most extensive compilations of the natural world that survived the Dark Ages. Pliny does not simply list materials and objects but also seeks explanations of phenomena. Thus he is the first to correctly describe the origin of amberas being the fossilized resin of pine trees. He makes the inference from the observation of trapped insects within some amber samples. The Naturalis Historiadivides neatly into the organic world of plants and animals, and the realm of inorganic matter, although there are frequent digressions in each section. He is especially interested in not just describing the occurrence of plants, animals and insects, but also their exploitation (or abuse) by man. The description of metalsand mineralsis particularly detailed, and valuable for the history of science as being the most extensive compilation still available from the ancient world. Ptolemysystematized the study of astronomy, drawing on the work of his predecessors to build astronomy upon a secure empirical basis and to demonstrate the relationship between astronomical observations and the resulting astronomical theory. His " Almagest" defined the method and subject matter of future astronomical research and the Ptolemaic systembecame the dominant model for the motions of the heavens. [Bernard R. Goldstein, "Saving the Phenomena: the Background to Ptolemy's Planetary Theory", "Journal for the History of Astronomy", 28(1997): 1-12.]
In like manner, the Roman-era physician
Galencodified and somewhat built upon Hellenistic knowledge of anatomyand physiology. His careful dissections and observations of dogs, pigs, and barbary apes, his descriptions (based on these and the works of earlier authors) of such structures as the nervous system, heartand kidneysand his demonstrations that, for instance, arteries carry blood instead of air became a central part of medical knowledge for well over a thousand years.
However, even though science continued under the Roman Empire,
Latintexts were mainly compilations drawing on earlier Greek work; advanced scientific research and teaching continued to be carried on in Greek. Meanwhile, such Greek and Hellenistic works as survived were preserved and developed in the Byzantine Empireand in the Islamic world. Late Roman attempts to translate Greek writings into Latin had limited success and direct knowledge of most ancient Greek texts only reached western Europe from the 12th centuryonwards. [Stahl, see esp. pp. 120-133.]
History of science in early cultures
Obsolete scientific theories
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* Clagett, Marshall. "Greek Science in Antiquity". New York: Collier Books, 1955.
* Cornford, F. M. Principium Sapientiæ: "The Origins of Greek Philosophical Thought". Cambridge: Cambridge Univ. Pr., 1952; Gloucester, Mass.: Peter Smith, 1971.
Lindberg, David C."The Beginnings of Western Science: The European Scientific Tradition in Philosophical, Religious, and Institutional Context, 600 B.C. to A.D. 1450". Chicago: Univ. of Chicago Pr., 1992. ISBN 0-226-48231-6.
* Lloyd, G. E. R. "Aristotle: The Growth and Structure of his Thought". Cambridge: Cambridge Univ. Pr., 1968. ISBN 0-521-09456-9.
* Lloyd, G. E. R. "Early Greek Science: Thales to Aristotle". New York: W.W. Norton & Co., 1970. ISBN 0-393-00583-6.
* Lloyd, G. E. R. "Greek Science after Aristotle". New York: W.W. Norton & Co., 1973. ISBN 0-393-00780-4.
* Lloyd, G. E. R. "Magic Reason and Experience: Studies in the Origin and Development of Greek Science". Cambridge: Cambridge Univ. Pr., 1979.
* Pedersen, Olaf. "Early Physics and Astronomy: A Historical Introduction". 2nd edition. Cambridge: Cambridge University Press, 1993. ISBN 0-521-40899-7.
* Stahl, William H. "Roman Science: Origins, Development, and Influence to the Later Middle Ages". Madison: Univ. of Wisconsin Pr., 1962.
* Thurston, Hugh. "Early Astronomy". New York: Springer, 1994. ISBN 0-387-94822-8.
* [http://www.history-of-physics.com/en/applets.htm Shockwave-Animations of ancient inventions]
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