Lucretius (c. 99–55 BCE)

Titus Lucretius Carus was a Roman poet and philosopher who is best remembered for his comprehensive epic On the Nature of Things. This remarkable work offered a dynamic worldview that departed significantly from the Aristotelian interpretation of this universe, life forms on earth, and the place our human species occupies within nature. Because his ideas differed greatly from those of the Greek thinker, Lucretius was not taken seriously by his contemporaries. In fact, his provocative thoughts on time, change, and reality would not be appreciated by scholars until his lost manuscripts were revived from philosophical oblivion during the Renaissance.

Aristotle had presented a geostatic and geocentric model of the universe. He separated the ethereal heavens from our material planet and claimed that the finite but eternal spherical cosmos is enclosed by a fixed ceiling of stars, each star equidistant from the earth. For him, both terrestrial linear motion and celestial circular motion are caused by the existence of the Unmoved Mover beyond the stars; this perfect entity of reflecting thought is the ultimate object that all desiring things attempt to emulate in terms of their development from potentiality to actuality. within his philosophical system, Aristotle taught that species are eternally fixed, with the human animal occupying the highest position in a static ladder of planetary organisms. Lucretius boldly challenged each of these basic Aristotelian assumptions.

Rejecting religious beliefs and ignorant superstitions, but indebted to the earlier thoughts of Epicurus, Lucretius presented a strictly naturalistic interpretation of and explanation for the existence of this eternal and infinite universe. He argued that endless reality consists only of material atoms and the void, there being no difference in makeup between celestial and terrestrial objects; thus, his natural philosophy taught the cosmic unity of all existence. Furthermore, Lucretius saw this dynamic universe as a creative process within which, over time, material atoms combine by chance to form an infinite number of stars, planets, and organisms. As a thoroughgoing naturalist, he taught that all objects and events are a part of an ongoing material reality that has no center, design, purpose, or goal.

For Lucretius, if there are immortal gods somewhere in this universe, then they have no interest in human existence. Nevertheless, with his powerful imagination, he speculated that life forms and intelligent beings (perhaps beings even superior to humans) exist elsewhere on other worlds throughout the cosmos. within this dynamic worldview, Lucretius glimpsed the forthcoming evolutionary framework. He held that, over time, the material earth itself gave birth to those plants and animals that now inhabit this planet, including our own species. Furthermore, for him, organic history is full of both creativity and extinction.

with exceptional insight, Lucretius outlined the sociocultural development of the human animal. In their prehistoric state, our naked but robust ancestors lived in caves and subsisted on pears, acorns, and berries. They wandered through the forests and woodlands searching for wild beasts (e.g., boars, lions, and panthers) with clubs and stones. Later, our ancestors wore animal skins, learned to use fire, and lived in nomadic hunting/ gathering societies that waged war. Over time, humans even developed the use of symbolic language as articulate speech. with the emergence of agriculture, they learned to cultivate plants and domesticate animals. Eventually, civilizations appeared and flourished, with people living in cities, using metals (first copper, then bronze, and later, iron), and developing art, law, and religion.

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