#Greek philosopher
- Anaxagoras — Anaxagoras of Clazomenae (c. 500 – 428 BC); a famous presocratic Greek philosopher who introduced into philosophical thought the structural notion of 'Nous' (the universal Mind or Reason) as an ordering force governing the primordial matter made of 'homeomeries' (eternal seeds of all things). He is historically recognized for moving the center of philosophy to Athens and for his rational explanations regarding eclipses and celestial phenomena.
- Anaximander — Anaximander of Miletus (c. 610 – 546 BC); a presocratic Greek philosopher of the Milesian school, disciple of Thales and master of Anaximenes. He is structurally recognized as the first thinker to have written a philosophical treatise in prose and to have identified the primordial principle of all things (arche) in the 'apeiron' (the boundless, infinite, or indefinite), an eternal substance in motion from which opposites separate.
- Anaximenes — Anaximenes of Miletus (c. 585 – 528 BC); a presocratic Greek philosopher, the last representative of the Milesian school, disciple of Anaximander. He structurally simplified the search for the primordial principle (arche) by identifying it as infinite air (aer), a divine and animated substance that, through the physical processes of rarefaction and condensation, gives rise to all elements and forms in the universe.
- Antisthenes — An ancient Greek philosopher from Athens (c. 445 – 365 BC), a direct disciple of Socrates and considered the founder of the Cynic school of philosophy. In the evolution of Western thought, Antisthenes laid the foundations of Cynic asceticism, arguing that virtue is the sole path to happiness (eudaimonia) and that it relies on self-control, the rejection of artificial social conventions, luxury, and material pleasures, directly influencing Diogenes of Sinope.
- Antisthenes — An international graphic variant, of French or alphabetically transposed Greek origin, for the name of the ancient Greek philosopher Antisthenes (the founder of the Cynic school). In older Romanian academic works, 19th-century literary translations, or specialized philosophical jargon, this form is occasionally used to preserve fidelity to the original or Western European spelling of the name of Socrates' disciple.
- Archelaus — The name borne by several prominent personalities from antiquity, including Archelaus of Miletus (a 5th-century BC Greek philosopher, disciple of Anaxagoras and master of Socrates, who posited that air and infinity are the principles of the universe) and Archelaus I (king of Macedon from 413 to 399 BC, famous for modernizing the army, building fortresses, and patronizing the arts, inviting Euripides to his court). The name derives structurally from the Greek 'Archelaos', meaning 'leader of the people'.
- Aristippus — Aristippus of Cyrene (c. 435–356 BCE), a renowned Greek philosopher, direct disciple of Socrates, and founder of the Cyrenaic school. He is considered the father of classical ethical hedonism, promoting the idea that immediate sensual and spiritual pleasure constitutes the supreme good and the ultimate goal of human existence. His profound thought was based on self-discipline and absolute detachment, being famous for his motto: 'I possess, but I am not possessed', illustrating the wise use of luxury without becoming its slave.
- Asclepiades — The name borne by several prominent personalities of Greek Antiquity. The most famous is Asclepiades of Bithynia (b. c. 124 BC), a renowned Greek physician and philosopher who practiced in Rome. He founded the methodical school of medicine, rejecting Hippocrates' humoral theory and advocating an atomistic theory stating that disease results from the blocked movement of atoms through body pores, promoting humane treatments such as massage, diet, and physical exercise.