Epictetus was a Greek Stoic philosopher who lived from around 55 to 135 CE. He was born a slave in Hierapolis, eventually gained his freedom, and founded a school of philosophy in Nicopolis, Greece. He is known for his practical teachings on how to live a virtuous and tranquil life, focusing on the distinction between what is in our control and what is not. His teachings, preserved in the Discourses and the Enchiridion, emphasize personal responsibility, inner freedom, and the acceptance of fate. He is one of the most influential Stoic thinkers, inspiring generations of philosophers and practitioners.

The dichotomy of control is Epictetus' most fundamental teaching. He argues that everything in life can be divided into two categories: what is within our control (our judgments, choices, desires, and actions) and what is not within our control (our body, property, reputation, health, and external events). He teaches that we should focus our energy and concern only on what is in our control, and accept everything else with equanimity. This distinction is the key to inner peace, freedom, and resilience, as it frees us from anxiety about things we cannot change.

Epictetus himself wrote nothing; his teachings were recorded by his student Arrian. The major works are the Discourses, a collection of conversations and lectures, and the Enchiridion (Handbook), a condensed summary of his essential teachings. The Discourses cover a wide range of topics, including ethics, logic, and physics, while the Enchiridion is a practical manual for daily living. Both works are written in a clear, direct style and have become classics of Stoic philosophy, widely read for their practical wisdom and timeless relevance.

For Epictetus, reason is the faculty that distinguishes humans from other beings and is the foundation of virtue and happiness. He taught that we must use reason to judge our impressions, evaluate our desires, and make wise choices. By cultivating rationality, we align our will with the natural order of the universe, which is governed by reason (the Logos). Reason helps us to distinguish between what is in our control and what is not, and to accept events as they unfold. A life guided by reason is a life of inner freedom and tranquility.

While both are major Stoic philosophers, Epictetus and Seneca differ in their life experiences and emphases. Seneca was a Roman statesman, wealthy and powerful, whose philosophy often reflects on political life, wealth, and the challenges of power. Epictetus, born a slave, writes from a perspective of poverty and social marginality, focusing more on personal inner freedom and resilience in the face of adversity. Seneca's works are more rhetorical and literary, while Epictetus' teachings are more direct, practical, and no-nonsense. Both, however, share core Stoic principles, including the primacy of virtue and the importance of inner control.

Impressions are the initial thoughts, perceptions, and judgments that arise in our minds in response to external events. Epictetus taught that while we cannot control the occurrence of impressions, we can control our assent to them. We can choose to accept, reject, or suspend judgment about an impression. For example, if a negative event occurs, we can choose to interpret it as a challenge to be faced rationally rather than a catastrophe. This process of disciplined judgment is central to his philosophy, as it allows us to maintain inner calm and act wisely in all circumstances.

Epictetus' teachings have had a profound influence on modern psychology, particularly cognitive-behavioral therapy (CBT), which emphasizes the role of thoughts and judgments in shaping emotional responses. His emphasis on the distinction between controllable and uncontrollable factors has been adopted in therapeutic approaches to anxiety and depression. His ideas have also influenced existentialist and humanist philosophers. His practical wisdom continues to be a source of guidance for those seeking resilience, self-mastery, and a meaningful life in the face of modern challenges.

The Enchiridion, or Handbook, is a short manual that summarizes Epictetus' essential teachings. It is designed as a practical guide for daily living, offering clear, direct advice on how to apply Stoic principles in everyday situations. It has been widely read and cherished for centuries, serving as an accessible introduction to Stoic philosophy. Its enduring popularity lies in its practical wisdom, which remains relevant for navigating the complexities of modern life. It is often the first Stoic text recommended to newcomers.