This document discusses the study of ethics. It defines ethics as the science of morality of human acts, derived from the Greek word meaning characteristic way of living. It discusses two ethical systems - the atheistic approach which assumes only matter exists, and the theistic approach which begins with God as the supreme lawgiver. Professional ethics regulates professions through moral codes of ethics. Human acts are defined as actions performed knowingly and freely, while acts of man are involuntary. Elicited acts are performed by the will without being bodily externalized, while commanded acts are done by mental or bodily powers under the will's command.