Onset to the Hellenistic Era to End of the Classical World

Pyrrho of Elis

Founder of Skepticism, taught to avoid certainty and suspend judgment to achieve inner peace (ataraxia).

Epicurus of Samos

Advocated for a life free from fear and pain by seeking moderate pleasures and denied the existence of an afterlife.

Antisthenes

Founder of Cynicism, rejected societal conventions in favor of self-sufficiency and influenced existential perspectives on well-being.

Diogenes of Sinope

Famous Cynic known for rejecting social norms and emphasizing living naturally, influencing discussions on authenticity in psychology.

Zeno of Citium

Founder of Stoicism, taught that virtue and reason are keys to happiness and that emotions should be controlled through rational thought.

Plotinus

Founder of Neoplatonism, emphasized a hierarchical universe and viewed happiness as attainable through reason and introspection.

Galen

Expanded on Hippocrates' theory of four humors, linking bodily fluids to personality types, shaping early personality psychology.

Augustine of Hippo

Integrated Neoplatonism and Stoicism into Christian theology, emphasizing free will and the pursuit of divine truth.