Concepts and theories of ethics

Ethics begins by clarifying its central words: good, right, justice, duty and obligation are not interchangeable. A theory is teleological when it judges actions by their ends or consequences, and deontological when it judges them by duty and principle regardless of outcome. For example, telling a lie to save a life divides the two approaches: the teleologist asks what outcome follows, while the deontologist asks whether lying itself violates duty.