Anaximander 610 B.C.–c. 546 B.C.
Anaximander is considered one of the most important of Presocratic philosophers, all of whom are concerned with the principle governing change in the natural world. Some accounts name him as the first Western philosopher, as he was the first to have developed a comprehensive scientific approach to the origin and guiding principles of the world. Anaximander constructs a cosmology based upon the apeiron, or the Bound less, which is itself an indeterminate substance which gave rise to all particular entities. Furthermore, he is credited by Diogenes Laertius not only with developing an original model of the universe and the foundations of life but with producing the first known map in the West and with being the first Greek author to write in prose.
whatsoever is known about Anaximander's life has been gleaned from various sources, some of which conflict in their accounts. Most histories place his birth in 610 B.C. in Miletus, a city in Ionia. Anaximander may have been a student of Thales and was at least well acquainted with Thales's ideas. Anaximander himself was followed by a philosopher named Anaximenes, and the three together are known as the Milesian philosophers. As a prominent citizen of Miletus, Anaximander conducted the colony of Apollonia on the Black Sea. Although it is less certain than that of his birth, there is general agreement that the date of Anaximander's death is approximately 546 B.C.
During his lifetime, Anaximander wrote at least four works, which were housed in the library at Alexandria: On Nature, Description of the Earth, The Fixed Stars, and Sphere. These titles, however, may actually be subtitles of a single work. Anaximander's contributions fall into four major areas: the structure of the natural order, the shape and position of the earth, the origin of living creatures, and the causes of meteorological phenomena. While Thales defines the foundation of all matter as water, Anaximander contends that any particular substance could not be the ground of all
other particular substances. His cosmology is based on the concept of apeiron (generally translated as the Boundless or the Infinite). The Boundless transcends all specific characteristics but falls into opposition in its actualization in the natural world. The most fundamental of these oppositions—wet-dry and hot-cold—cause all motion and change in the universe. Anaximander claims that these cosmic forces are in continual conflict: any increase of water is an encroachment on dryness. Changes in the natural order therefore can be attributed to "justice," by which the "wrongdoing" of each force is counteracted by an equal and opposite force.
The only extant fragment of Anaximander's writing survived as part of a historical work by Theophrastus, a student of Aristotle. Theophrastus's study of the Presocratic philosophers was a resource for Aristotle's Physics. Theophrastus' writing is only indirectly preserved in the commentary on Aristotle's Physics by Simplicius entitled "Of the Opinions of the Physicists." Aristotle frequently refers to Anaximander in various extant works, and the Doxographers, who in the first century A.D. began studying Presocratic philosophy, also draw on Anaximander's work. However, all of these sources present problems of interpretation: Theophrastus's historical survey is highly schematic and only excerpted and paraphrased Anaximander's own writing; Aristotle refers to Anaximander without citation and tends to interpret rather than directly report on Presocratic ideas; Simplicius' work is thrice removed from Anaximander's text; the Doxographers approach their studies with particular interests and ultimately rely on Theophrastus' historical survey for information on Anaximander.
Anaximander's immediate successor—Anaximenes, the third of the Milesian philosophers—incorporates aspects of both Thales's and Anaximander's innovations. Although he retains the notion of the Boundless, he considers the world-substance to be air, which is held to divine status. Thus, Anaximenes's system returns to a natural order controlled by divine forces that could initiate change. Anaximander rejects the idea that the natural world is governed by the highly arbitrary and personified influence of deities and instead seeks a universal law by which nature can be understood as a system. Because of this move towards science, many historians consider Anaximander to be the first philosopher. His attempt to construct a system that unites science and philosophy places Anaximander at the beginning of a long tradition of rational inquiry, and his early innovations in the study of the natural world make him a significant figure in the history of Western philosophy.