Anaximander

Anaximander (Ἀναξίμανδρος, Anaxímandros; Anaximander; /ˌænəˈsɪməndər/) was a pre-Socratic philosopher from Miletus in Ionia; a student of Thales, Anaximander contributed significantly to early philosophical thought, particularly in cosmology, geography, and biology. He is often regarded as the first philosopher to write down his studies, producing a work that some have called the first philosophical treatise, although the text itself has not survived except in fragments quoted by later writers.

The Boundless (Ἄπειρον, Ápeiron) or Infinite (Ἄπειρον, Ápeiron) was Anaximander's idea of the originating principle (archē) of the cosmos. Unlike Thales, who posited water as the fundamental substance, Anaximander argued that the source of all things must be something indefinite and unlimited, from which all the elements emerge and to which they return upon their destruction. Anaximander's cosmological model described the earth as a cylindrical shape floating free in the center of an infinite void, an idea revolutionary for its time. He theorized that the heavens were rings of fire, with the stars, sun, and moon existing as openings in these rings that allowed light to escape or be obscured. He was the first Greek philosopher was the first to develop a cosmology (a systematic, philosophical view of the world).

Anaximander postulated eternal motion, along with the apeiron, as the originating cause of the world. This (probably rotary) motion caused opposites, such as hot and cold, to be separated from one another as the world came into being. However, the world is not eternal and will be destroyed back into the apeiron, from which new worlds will be born. Thus, all existing things must “pay penalty and retribution to one another for their injustice, according to the disposition of time,” as he rather figuratively expressed it.

Anaximander also speculated on the origins of human life, suggesting that humans and other animals originated from the sea. This early form of evolutionary theory posited that life began in a moist environment and that humans had developed from fish-like creatures, a radical idea that prefigured evolutionary concepts by millennia. He is credited with creating one of the first maps of the known world, contributing significantly to the field of geography and cartography. His map included the known parts of the world at the time, offering a speculative but systematic approach to understanding the earth's geography.

He is also attributed with the introduction of the gnomon to Greece, a simple astronomical instrument used to measure the sun's height and to determine the equinoxes, solstices, and geographical latitudes. Anaximander's work laid the groundwork for later pre-Socratic philosophers, including his pupil Anaximenes. His concept of the ápeiron influenced subsequent philosophical thought, including the work of Plato and Aristotle, who engaged with and critiqued his ideas.

In his thinking about Earth, he regarded the inhabited portion as flat, consisting of the top face of a cylinder, whose thickness is one-third its diameter. Earth is poised aloft, supported by nothing, and remains in place because it is equidistant from all other things and thus has no disposition to fly off in any one direction. He held that the Sun and the Moon are hollow rings filled with fire; their disks are vents or holes in the rings, through which the fire can shine. The phases of the Moon, as well as eclipses of the Sun and the Moon, are due to the vents closing up. Anaximander also discussed the causes of meteorological phenomena, such as wind, rain, and lightning.

While Thales had already dispensed with divine explanations of the world around him, he had not written a book about his philosophy. Moreover, Anaximander went much further in trying to give a unified account of all of nature. Although Anaximander’s primitive astronomy was soon superseded, his effort to provide a rational explanation of the world had a lasting influence. Through his efforts in mapping and astronomy, Anaximander contributed to the early development of scientific inquiry, moving Greek thought further from mythological explanations of the world to more empirical and rational understandings.

The knowledge of Anaximander's philosophy comes from later philosophers and historians, such as Aristotle, Theophrastus, and Simplicius, who provided summaries and analyses of his work. The fragmentary nature of these sources means that interpretations of Anaximander's thought must be approached with caution. Modern scholars continue to study Anaximander's fragments and testimonies to understand better his contributions to philosophy and science. His work is seen as a pivotal moment in the intellectual history of the West, representing a move towards a more abstract and rational explanation of the natural world.