Epicureanism. Major Thinkers include Epicurus (d. 270 BCE) and Lucretius (95-55 BCE). Key Concepts. Greatest good comes from peace of mind (ataraxia) and pleasure (lack of bodily pain). Pleasure can be found in knowledge, friendship, and living a virtuous and temperate life. Since eternal atoms make up existence, individuals should control lives without fear of God or death. No call for social duty.