17. Stoicism
Stoicism teaches the cultivation of virtue, resilience, and acceptance of what we cannot control. Ancient philosophers such as Marcus Aurelius and Epictetus encouraged individuals to focus on their inner character and respond to challenges with wisdom and composure. Stoic principles have experienced a resurgence in modern life, influencing approaches in therapy, leadership, and self-help by emphasizing emotional resilience, mindfulness, and a clear sense of purpose.