Science in classical antiquity
Science in classical antiquity encompasses inquiries into the workings of the world or universe aimed at both practical goals as well as more abstract investigations belonging to natural philosophy. Classical antiquity is traditionally defined as the period between the 8th century BC and the 6th century AD. It is typically limited geographically to the Greco-Roman West, Mediterranean basin, and Ancient Near East, thus excluding traditions of science in the ancient world in regions such as China and the Indian subcontinent.
Ideas regarding nature that were theorized during classical antiquity were not limited to science but included myths as well as religion. Those who are now considered as the first scientists may have thought of themselves as natural philosophers, as practitioners of a skilled profession, or as followers of a religious tradition. Some of the more widely known figures active in this period include Hippocrates, Aristotle, Euclid, Archimedes, Hipparchus, Galen, and Ptolemy. Their contributions and commentaries spread throughout the Eastern, Islamic, and Latin worlds and contributed to the birth of modern science. Their works covered many different categories including mathematics, cosmology, medicine, and physics.
Classical Greece
Knowledge of causes
This subject inquires into the nature of things first began out of practical concerns among the ancient Greeks. For instance, an attempt to establish a calendar is first exemplified by the Works and Days of the Greek poet Hesiod, who lived around 700 BC. Hesiod's calendar was meant to regulate seasonal activities 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. 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.Medicine is another area where practically oriented investigations of nature took place during this period. 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. 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.
An example of the search for causal explanations is found in the Hippocratic text On the Sacred Disease, which deals with the nature of epilepsy. In it, the author attacks his rivals for their ignorance in attributing epilepsy to divine wrath, and for their love of gain. Although the author insists that epilepsy has a natural cause, when it comes to explain what that cause is and what the proper treatment would be, the explanation is as short on specific evidence and the treatment as vague as that of his rivals. Nonetheless, observations of natural phenomena continued to be compiled in an effort to determine their causes, as for instance in the works of Aristotle and Theophrastus, who wrote extensively on animals and plants. Theophrastus also produced the first systematic attempt to classify minerals and rocks, a summary of which is found in Pliny's Natural History.
The legacy of Greek science in this era included substantial advances in factual knowledge due to empirical research, an awareness of the importance of certain scientific problems, and a recognition of the methodological significance of establishing criteria for truth, despite the lack of universal consensus in any of these areas.
Pre-Socratic philosophy
Materialist philosophers
The earliest Greek philosophers, known as the pre-Socratics, were materialists who provided alternative answers to the same question found in the myths of their neighbors: "How did the ordered cosmos in which we live come to be?" 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.Thales of Miletus considered that all things came to be from and find their sustenance in water. Anaximander 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. Anaximenes returned to a concrete material substance, air, which could be altered by rarefaction and condensation. He adduced common observations to demonstrate that air was a substance and a simple experiment to show that it could be altered by rarefaction and condensation.
Heraclitus of Ephesus, then maintained that change, rather than any substance was fundamental, although the element fire seemed to play a central role in this process. Finally, Empedocles of Acragas, seems to have combined the views of his predecessors, asserting that there are four elements which produce change by mixing and separating under the influence of two opposing "forces" that he called Love and Strife.
All these theories imply that matter is a continuous substance. Two Greek philosophers, Leucippus and Democritus 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. 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.
Xenophanes of Colophon prefigured paleontology and geology as he thought that periodically the earth and sea mix and turn all to mud, citing several fossils of sea creatures that he had seen.
Pythagorean philosophy
The materialist explanations of the origins of the cosmos were attempts at answering the question of how an organized universe came to be; however, the idea of a random assemblage of elements producing an ordered universe without the existence of some ordering principle remained problematic to some.One answer to this problem was advanced by the followers of Pythagoras, who saw number as the fundamental unchanging entity underlying all the structure of the universe. Although it is difficult to separate fact from legend, it appears that some Pythagoreans believed matter to be made up of ordered arrangements of points according to geometrical principles: triangles, squares, rectangles, or other figures. Other Pythagoreans saw the universe arranged on the basis of numbers, ratios, and proportions, much like musical scales. Philolaus, for instance, held that there were ten heavenly bodies because the sum of 1 + 2 + 3 + 4 gives the perfect number 10. Thus, the Pythagoreans were some of the first to apply mathematical principles to explain the rational basis of an orderly universe—an idea that was to have immense consequences in the development of scientific thought.
Hippocrates and the Hippocratic Corpus
According to tradition, the physician Hippocrates of Kos is considered the "father of medicine" because he was the first to make use of prognosis and clinical observation, to categorize diseases, and to formulate the ideas behind humoral theory. However, most of the Hippocratic Corpus—a collection of medical theories, practices, and diagnoses—was often attributed to Hippocrates with very little justification, thus making it difficult to know what Hippocrates actually thought, wrote, and did.Despite their wide variability in terms of style and method, the writings of the Hippocratic Corpus had a significant influence on the medical practice of Islamic and Western medicine for more than a thousand years.
Schools of philosophy
The Academy
The first institution of higher learning in Ancient Greece was founded by Plato, an Athenian who—Plato's philosophy maintained that all material things 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 demonstrative knowledge cannot be achieved by looking at the imperfect material world. Truth is to be found through rational argumentation, analogous to the demonstrations of mathematicians. For instance, Plato recommended that astronomy be studied in terms of abstract geometrical models rather than empirical observations, and proposed that leaders be trained in mathematics in preparation for philosophy.
Aristotle studied at the Academy and nonetheless disagreed with Plato in several important respects. While he agreed that truth must be eternal and unchanging, Aristotle maintained that the world is knowable through experience and that we come to know the truth by what we perceive with our senses. For him, directly observable things are real; ideas only exist as they express themselves in matter, such as in living things, or in the mind of an observer or artisan.
Aristotle's theory of reality led to a different approach to science. Unlike Plato, Aristotle emphasized observation of the material entities which embody the forms. He also played down the importance of mathematics in the study of nature. The process of change took precedence over Plato's focus on eternal unchanging ideas in Aristotle's philosophy. Finally, he reduced the importance of Plato's forms to one of four causal factors.
Aristotle thus distinguished between four causes:
- the matter of which a thing was made.
- the form into which it was made.
- the agent who made the thing.
- the purpose for which the thing was made.