
Writing in a letter to his friend Lucilius around AD62, the Roman philosopher Seneca outlined two arguments for vegetarianism. The first argument came from a Roman philosopher called Sextius whom Seneca particularly admired, who had lived in the first century BC and had been known for his simple lifestyle.
Sextius argued that humans can get all the nutrition we need from eating plants. This means that killing animals for food is done purely for the pleasure derived from eating meat. Sextius believed that killing animals for pleasure makes people develop the habit of cruelty. Morally speaking, people shouldn’t develop the habit of cruelty, so we shouldn’t kill animals just for the pleasure of eating meat.