This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Named philosophical schools built around a founder, a teaching lineage and a body of texts arose independently in several traditions long before anyone tried to compare them. India's six orthodox darshanas, Nyaya, Vaisheshika, Samkhya, Yoga, Mimamsa and Vedanta, each systematized a distinct method of reasoned inquiry toward liberation, disagreeing with one another on logic, causation and the nature of the self while sharing acceptance of the Vedas as authoritative. China's Warring States period produced its own rival systems in the same few centuries, Confucianism, Daoism, Legalism and Mohism among them, each proposing a different account of how a person and a state should be ordered, and arguing against the others by name.
Greek philosophy organized itself around physical schools tied to a place and a founder: Plato's Academy, Aristotle's Lyceum, the Stoa where the Stoics taught, and the Garden where Epicurus taught. When later Islamic philosophers, al-Kindi, al-Farabi and Avicenna among them, engaged with Greek texts newly available in Arabic translation, they did not simply repeat them; they produced falsafa, a new synthesis that argued with the inherited Aristotelian and Neoplatonic material on its own terms and became its own documented school tradition in turn.
Comparative study of philosophical schools traces doctrine, but it also traces transmission, teacher to student lineages, the texts a school considered authoritative, and how long an institutional home for the school persisted, since a school's ideas and its institutional survival are two different facts that do not always track together: a school's texts can outlive its teaching institution by centuries, as happened to several of the Hellenistic schools whose writings were still read and debated long after their original physical schools had closed.