Stoicism
A Hellenistic philosophy founded by Zeno of Citium, holding that virtue is the only good and that accepting fate brings tranquility.
Virtue ethics: The view that moral character, not consequences or rules, is the basis of ethical evaluation. Stoicism is one of the three principal ancient virtue theories, alongside Aristotle's and Epicurus's rivals.
Zeno of Citium: Phoenician-born merchant who founded Stoicism in Athens around 300 BC after shipwreck ended his trading career. The founder whose teaching in the Stoa Poikile gave the school its name.
Chrysippus: Third head of the Stoa, systematized Stoic logic and physics; over 700 works, none surviving intact. Without his systematization, early Stoicism would not have survived as a coherent doctrine.
Epicureanism: The rival Hellenistic school teaching that pleasure, understood as tranquility, is the highest good. On happiness, gods, and death the two schools take nearly opposite positions at every point.
Natural law: The doctrine that moral law derives from nature or reason, binding all humans equally. Stoic cosmopolitanism and rational law fed directly into Roman legal theory and beyond.
Dichotomy of control: Epictetus's division of things into what is up to us (judgment, desire) and what is not (health, reputation, wealth). The practical core of Stoic training: peace comes from caring only about the former.
Stoa Poikile: The painted porch in Athens where Zeno taught, from which the school takes its name. The literal birthplace of the school and the source of its name.
Epictetus: Former slave turned teacher whose Discourses and Enchiridion made Stoicism a practical discipline. His dichotomy of control is the most cited Stoic idea in the modern revival.
Aristotelianism: Aristotle's philosophy, holding that flourishing needs virtue plus external goods like friendship and health. The Stoic claim that externals are valueless is a direct answer to Aristotle.
Cognitive behavioral therapy: A psychotherapy treating distress by changing the beliefs and judgments that generate it. Albert Ellis and Aaron Beck explicitly drew Stoic techniques for rethinking judgments.