Origin...

Origin, in astronomy, of the dual: systematic, fixed stellar system and chaotic, dynamic terrestrial world. Ethics, too, rooted in number-mysticism 2.2.1.2 Problem of change arises from the intuition that something from nothing is impossible Problem of Change: Qualitative Theories of Change: Empedocles [495-435 BCE] and Anaxogoras [500-428 BCE]. Quantitative theories: Atomism: transition from teleology to mechanism: Leucippus and Democritus [460-370 BCE].

Metaphysics, cosmology, psychology, theory of knowledge, theology and ethics Heraclitus [535-475 BCE] born Ephesus: [^1] Fire and universal flux, [^2] opposites and their union, [^3] harmony and the law Eleatic School: Xenophanes [570-480 BCE] Colophon, precursor, first basis of skepticism in Greek thought, Parmenides founder of philosophy of permanence change is relative: combination and separation [becoming]paradoxes of being and nonbeing, Zeno [of the paradoxes] [490-430 BCE] and Melisus of Samos are defenders of the doctrine Democritus: same concept in atomic form.

Metaphysics, ontology: space: nonbeing exists; motion in space: atomic. Psychology, theory of knowledge: information from object to sentient: propagation of actions through toms in air, soul atoms: the finest in-between body atoms 2.2.2 Age of sophists The development of Greek thought led to a spirit of free inquiry in poetry: Aeschylus [525-456 BCE], Sophocles [490=405 BCE], Euripedes [480-406 BCE]; history: Thucydides [b. 471 BCE]; medicine: Hippocrates [b. 460 BCE].

The construction of philosophical systems ceases temporarily; the existing schools continue to be taught and some turn attention to natural-scientific investigation The resulting individualism made an invaluable contribution to Greek thought but led, finally, to an exaggerated intellectual and ethical subjectivism. The Sophists who were originally well-regarded came gradually to be a term of reproach partly owing to the radicalism of the later schools: their subjectivism, relativism and nihilism.

For Protagoras, all opinions are true [though some "better"]; for Gorgias none are true [there is nothing; even if there were something we could not know it; if we could know it we could not communicate it].