Altruism refers to helping or benefiting others at some cost or sacrifice to oneself. It originated from the Italian word 'alturi' meaning 'other people'. While altruism is commonly understood as concern for others' well-being, some philosophers and scientists argue that true altruism does not exist based on evidence from sociology, neurobiology, and religion. These fields provide examples of how altruistic behavior may ultimately benefit oneself through kin selection, brain rewards, or religious teachings.