Ancient Greek epistemologists

Aristotle (; 384–322 BC) was an ancient Greek philosopher and polymath. His writings cover a broad range of subjects spanning the natural sciences, philosophy, linguistics, economics, politics, psychology, and the arts. As the founder of the Peripatetic school of philosophy in the Lyceum in Athens, he began the wider Aristotelian tradition that followed, which set the groundwork for the development of modern science.

Plato ( ; Greek: , ; born  BC, died 348/347 BC) was an ancient Greek philosopher of Classical Athens who is most commonly considered the foundational thinker of the Western philosophical tradition. An innovator of the literary dialogue and dialectic forms, Plato influenced all the major areas of theoretical philosophy and practical philosophy, and was the founder of the Academy, a philosophical school in Athens where Plato taught the collection of philosophical theories that would later become known as Platonism.

Socrates (; ; – 399 BC) was an ancient Greek philosopher from Classical Athens, perhaps the first Western moral philosopher, and a major inspiration on his student Plato, who largely founded the tradition of Western philosophy. An enigmatic figure, Socrates authored no texts and is known mainly through the posthumous accounts of classical writers, particularly his students Plato and Xenophon. These accounts are written as dialogues, in which Socrates and his interlocutors examine a subject in the style of question and answer; they gave rise to the Socratic dialogue literary genre. Contrad

Democritus (, ; , Dēmókritos, meaning "chosen of the people"; – ) was an Ancient Greek pre-Socratic philosopher from Abdera, primarily remembered today for his formulation of an atomic theory of the universe. Democritus wrote extensively on a wide variety of topics.

Epicurus (, ; ; 341–270 BC) was an ancient Greek philosopher who founded Epicureanism, a highly influential school of philosophy; it asserted that philosophy's purpose is to attain as well as to help others attain tranquil lives, characterized by freedom from fear and the absence of pain.

Heraclitus (; ; ) was an ancient Greek pre-Socratic philosopher from the city of Ephesus, which was then part of the Persian Empire. He exerts a wide influence on Western philosophy, both ancient and modern, through the works of such authors as Plato, Aristotle, the Stoics, Georg Wilhelm Friedrich Hegel, Friedrich Nietzsche, and Martin Heidegger.

Protagoras ( ; ; ) was a pre-Socratic Greek philosopher and rhetorical theorist. He is numbered as one of the sophists by Plato. In his dialogue Protagoras, Plato credits him with inventing the role of the professional sophist.

Plotinus (; , Plōtînos;  – 270 CE) was a Hellenistic Greek philosopher, born and raised in Roman Egypt. Plotinus is regarded by modern scholarship as the founder of Neoplatonism.

Xenophanes of Colophon ( ; ; – c. 478 BC) was a Greek philosopher, theologian, poet, and critic of Homer. He was born in Ionia and travelled throughout the Greek-speaking world in early classical antiquity.

Greek philosopher (c. 495 – c. 430 BC)

2nd-century Roman philosopher and physician

Pyrrho of Elis (; ; ) was a Greek philosopher of Classical antiquity, credited as being the first Greek skeptic philosopher and founder of Pyrrhonism.

Arcesilaus (; ; 316/5–241/0 BC) was a Greek Hellenistic philosopher. He was the founder of Academic Skepticism and what is variously called the Second or Middle or New Academy – the phase of the Platonic Academy in which it embraced philosophical skepticism.

Aenesidemus ( or Αἰνεσίδημος) was a 1st-century BC Greek Pyrrhonist philosopher from Knossos who revived the doctrines of Pyrrho and introduced ten skeptical "modes" (tropai) for the suspension of judgment. He broke with the Academic Skepticism that was predominant in his time, synthesizing the teachings of Heraclitus and Timon of Phlius with philosophical skepticism. Although his primary work, the Pyrrhonian Discourses, has been lost, an outline of the work survives from the later Byzantine Empire, and the description of the modes has been preserved by a few ancient sources.

Greek Pyrrhonist philosopher (c.320–c.235 BC)

Skeptic philosopher