Eleatics

The Eleatics were a school of pre-Socratic philosophy based in Elea (present-day Velia, Italy), active in the early 5th century BCE. Its most prominent figures were Parmenides and Zeno of Elea, with later contributions from Melissus of Samos. The school is known for its rationalist approach to ontology and its challenge to common sense.

They argued for monism: Being is, and non-being cannot exist. Reality is one, ungenerated, indivisible, and unchanging; change and multiplicity are appearances of sense experience. The senses mislead; reason reveals truth. Parmenides distinguished between the Way of Truth and the Way of Opinion; the former asserts the unity and immutability of Being, the latter is the domain of belief and sensory illusion.

Zeno's paradoxes: Zeno of Elea argued to defend Parmenides' view by showing that motion and plurality would lead to contradictions. Notable paradoxes include Achilles and the Tortoise, the Dichotomy, and the Arrow.

Melissus and legacy: Melissus of Samos extended Eleatic argument to assert that Being is single, continuous, and unbounded, with no void or empty space. The Eleatics influenced later Greek thought, notably Plato’s theory of forms and metaphysical speculation, and contributed to early debates in ontology, logic, and epistemology. The school's influence waned by the end of the 5th century BCE as other philosophies, including Heraclitus, Pythagoreans, and the early Sophists, offered alternatives.