Hellenistic schools of thought

· Cynicism

· Eclecticism

· Epicureanism

· Middle Platonism

· Neo-Platonism

· Neopythagoreanism

· Peripatetic School

· Pyrrhonism

· Stoicism

· Sophism

Socrates (/ˈsɒkrətiːz/;^[2] Greek: Σωκράτης Sōkrátēs [sɔːkrátɛːs]; 470/469 BC – 399 BC) was a classical Greek (Athenian) philosopher credited as one of the founders of Western philosophy. He is an enigmatic figure known chiefly through the accounts of classical writers, especially the writings of his students Plato and Xenophon and the plays of his contemporary Aristophanes. Plato's dialogues are among the most comprehensive accounts of Socrates to survive from antiquity, though it is unclear the degree to which Socrates himself is "hidden behind his 'best disciple', Plato".

Through his portrayal in Plato's dialogues, Socrates has become renowned for his contribution to the field of ethics, and it is this Platonic Socrates who lends his name to the concepts of Socratic irony and the Socratic method, or elenchus. The latter remains a commonly used tool in a wide range of discussions, and is a type of pedagogy in which a series of questions is asked not only to draw individual answers, but also to encourage fundamental insight into the issue at hand. Plato's Socrates also made important and lasting contributions to the field of epistemology, and the influence of his ideas and approach remains a strong foundation for much western philosophy that followed.

Plato (/ˈpleɪtoʊ/; Greek: Πλάτων, Plátōn, "broad"; 428/427 or 424/423 BCE – 348/347 BCE) was a philosopher, as well as mathematician, in Classical Greece, and an influential figure in philosophy, central in Western philosophy. He was Socrates' student, and founded the Academy in Athens, the first institution of higher learning in the Western world. Along with Socrates and his most famous student, Aristotle, Plato helped to lay the foundations of Western philosophy and science. Alfred North Whitehead once noted: "the safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato."

Plato's dialogues have been used to teach a range of subjects, including philosophy, logic, ethics, rhetoric, religion and mathematics. His theory of Forms began a unique perspective on abstract objects, and led to a school of thought called Platonism. Plato's writings have been published in several fashions; this has led to several conventions regarding the naming and referencing of Plato's texts.

Aristotle (Aristatolie) (/ˈærɪˌstɒtəl/; Greek: Ἀριστοτέλης [aristotélɛːs], Aristotélēs; 384–322 BCE) was a Greek philosopher and scientist born in the Macedonian city of Stagirus, in 384 BCE. His father, Nicomachus, died when Aristotle was a child, whereafter Proxenus of Atarneus became his guardian. At eighteen, he joined Plato's Academy in Athens and remained there until the age of thirty-seven (c. 347 BCE). His writings cover many subjects – including physics, biology, zoology, metaphysics, logic, ethics, aesthetics, poetry, theater, music, rhetoric, linguistics, politics and government – and constitute the first comprehensive system of Western philosophy. Shortly after Plato died, Aristotle left Athens and, at the request of Philip of Macedon, tutored Alexander the Great between 356 and 323 BCE. According to the Encyclopædia Britannica, "Aristotle was the first genuine scientist in history ... [and] every scientist is in his debt."

Teaching Alexander the Great gave Aristotle many opportunities and an abundance of supplies. He established a library in the Lyceum which aided in the production of many of his hundreds of books. The fact that Aristotle was a pupil of Plato contributed to his former views of Platonism, but, following Plato's death, Aristotle immersed himself in empirical studies and shifted from Platonism to empiricism.^[5] He believed all peoples' concepts and all of their knowledge was ultimately based on perception. Aristotle's views on natural sciences represent the groundwork underlying many of his works.

Aristotle's views on physical science profoundly shaped medieval scholarship. Their influence extended into the Renaissance and were not replaced systematically until the Enlightenment and theories such as classical mechanics. Some of Aristotle's zoological observations were not confirmed or refuted until the 19th century.^{[examples needed]} His works contain the earliest known formal study of logic, which was incorporated in the late 19th century into modern formal logic.

In metaphysics, Aristotelianism profoundly influenced Judeo-Islamic philosophical and theological thought during the Middle Ages and continues to influence Christian theology, especially the scholastic tradition of the Catholic Church. Aristotle was well known among medieval Muslim intellectuals and revered as "The First Teacher" (Arabic: المعلم الأول‎).

His ethics, though always influential, gained renewed interest with the modern advent of virtue ethics. All aspects of Aristotle's philosophy continue to be the object of active academic study today. Though Aristotle wrote many elegant treatises and dialogues – Cicero described his literary style as "a river of gold" – it is thought that only around a third of his original output has survived.