Final answer:
Epicurus's fundamental claim is that pleasure is the highest good and pain is bad, advocating for a life of moderation, virtue, and wisdom to achieve pleasure and tranquility. His philosophy, known as Epicureanism, suggests that living well involves managing desires, being self-sufficient, and overcoming the fear of death.
Step-by-step explanation:
Epicurus's fundamental claim about the nature of the good and the bad is that pleasure is the highest good and pain is the equivalent of bad. Contrary to what might be a common misconception, Epicurus's concept of pleasure was nuanced and recommended moderation, virtue, and philosophy as pathways to the most pleasurable life. Epicureanism emphasized achieving ataraxia (tranquility), by managing desires, seeking freedom from fear—especially the fear of death—and living a self-sufficient life as methods for living well. Epicurus's hedonism was not about hedonistic indulgence, but rather a sophisticated understanding of living a pleasurable life through simple, moderate actions and a deep understanding of human nature.
The Epicureans viewed ethics as grounded in the natural world and believed that the ultimate goal of life is to pursue pleasure, using reason as the guide for human existence. They were empirical philosophers who believed that knowledge comes from sense experience. As such, Epicureans would turn away from public life, focusing instead on contemplative living in philosophical communities. Prevention of suffering and seeking of pleasure was best achieved by minimizing dependencies on others and facing both the inevitability and the naturalness of death without fear.