Anaximander of Miletus
c. 610-c. 547 B.C.
Greek Philosopher
Anaximander is famous for introducing the concept of the apeiron—the first use of an unobservable entity to explain empirical phenomena. He also developed the first geometrical model of the universe, drew the first Greek map of the inhabited world, produced the first Greek star-map and celestial globe, and adapted the gnomon sundial for measuring the hours of the day and annual variations in the Sun's path. His now lost work, On the Nature of Things, is believed to be the first scientific treatise.
Anaximander was born around 610 B.C.in Miletus, which at the time was the most powerful Greek city in Asia Minor. Little is known of his life. Tradition has it that he was a younger friend of Thales (c. 624-c. 546 B.C.), possibly his student. Regardless, Anaximander was clearly influenced by Thales. The only other detail we have concerning his life is the unsubstantiated report that he led a Milesian colony to Apollonia on the Black Sea.
Thales was the first thinker to describe the world in terms of the modifications of nature itself. He taught that the apparent chaos of the cosmos conceals an underlying permanence rooted in the substance of which the world is composed. He believed this primary substance, or arche, to be water (hydor). Thales was certainly influenced by myth, but his determination to fit his observations and beliefs into a rational scheme represented a radical break with previous modes of thought. This critical spirit and emphasis on natural causes was the hallmark of Milesian physical speculation about the origins of the world.
Anaximander agreed with Thales that a single substance underlies the plurality and apparent chaos of the cosmos but objected to his choice of water. According to Anaximander, the cosmos is composed of a warring concourse of opposites. There are two sets of opposites in continual conflict: (1) hot and cold, and (2) wet and dry. Observations revealed to him that when one element is in abundance, it has a tendency to consume its opposite. Thus, a particular element, such as water (wet), could not be the arche of all things because it would initially have to exist in sufficient quantity to give rise to the world. In such a state, it would enjoy permanent dominance over its potential opposite (dry), thereby preventing it from ever coming into existence.
To explain the origin and nature of the cosmos, Anaximander postulated as arche an undifferentiated mass of enormous extent that he called the apeiron or the "boundless." He understood the apeiron to be both spatially and temporally unbounded and without internal distinctions. The primary opposites were conceived of as potentialities of the apeiron that emerged by virtue of its eternal motions. Though unobservable and in all ways transcending the processes of this world, the apeiron circumscribes and governs all natural phenomena. Thus, with the introduction of the apeiron, Anaximander became the first to attempt an explanation of the perceptible in terms of the imperceptible.
In On the Nature of Things Anaximander described the universe as spherical with Earth occupying a stable position at its center. He argued that Earth had no reason to fall in particular any direction since it was equidistant from every point on the periphery of the celestial sphere. This symmetry argument was the first to reject the idea of a physical support for Earth.
Anaximander created the first mechanical planetary theory, imagining heavenly bodies to be fire-filled wheels rotating about Earth. He also realized Earth's surface must be curved to account for the changing position of stars. Thus, he conceived of Earth as a convex cylinder whose height was one-third its width.
This is the complete article, containing 603 words
(approx. 2 pages at 300 words per page).
