Ancient Greek logicians

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.

Aelius Galenus or Claudius Galenus (; September 129 – CE), often anglicized as Galen () or Galen of Pergamon, was a Roman and Greek physician, surgeon, and philosopher. Considered to be one of the most accomplished of all medical researchers of antiquity, Galen influenced the development of various scientific disciplines, including anatomy, physiology, pathology, pharmacology, and neurology, as well as philosophy and logic.

Theophrastus (; ; c. 371 – c. 287 BC) was an ancient Greek philosopher and naturalist. A native of Eresos in Lesbos, he was Aristotle's close colleague and successor as head of the Lyceum, the Peripatetic school of philosophy in Athens. Theophrastus wrote numerous treatises across all areas of philosophy, working to support, improve, expand, and develop the Aristotelian system. He made significant contributions to various fields, including ethics, metaphysics, botany, and natural history. Often considered the "father of botany" for his groundbreaking works "Enquiry into Plants" () and "On the

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

Chrysippus of Soli (; , ; ) was a Greek Stoic philosopher. He was a native of Soli, Cilicia, but moved to Athens as a young man, where he became a pupil of the Stoic philosopher Cleanthes. When Cleanthes died, around 230 BC, Chrysippus became the third head of the Stoic school. A prolific writer, Chrysippus expanded the fundamental doctrines of Cleanthes' mentor Zeno of Citium, the founder and first head of the school, which earned him the title of the Second Founder of Stoicism.

ancient Greek philosopher

Greek philosopher and dialectician (died c. 284 BC)

ancient Greek philosopher

Alexinus (; ; –265 BC) of Elis, was a philosopher of Megarian school and a disciple of Eubulides. From his argumentative nature he was facetiously named the wrangler (), From Elis he went to Olympia, hoping to found a sect which was to be called the Olympian, but his disciples soon became disgusted with the unhealthiness of the place and their scanty means of subsistence, and left him with a single attendant.