The word deontology comes from the Greek words for duty and science. Deontology acts as a moral guide to assess choices of what a person ought to do in contrast to what kind of person someone should be¹. Deontology is sometimes described as duty or rule-based ethics because rules bind one to their duty¹. Additionally, deontologists stand in direct opposition to consequentialists.
Kantianism is considered to be deontological for several reasons. First, Kant argues that to act in the morally right way, people must act from duty². Second, Kant argues that it is not the consequences of actions that make them right or wrong but the motives of the person who carries out the actions².
Some deontologists are moral absolutists and believe that certain actions are absolutely right or wrong regardless of the intentions behind them¹. Immanuel Kant argues that the only absolutely good thing is a good will². For example, if a person has the idea that they will lie, then their action is wrong even if good comes out of it. This is in opposition to non-abolitionists who believe that the outcome makes the action right.
The divine command theory is sometimes related to deontology and states that an action is right if God has decreed that it is right¹. These philosophers believe that moral obligations arise from God’s commands.
2. Kant, Immanuel. 1780. “Preface”. In The Metaphysical Elements of Ethics. Translated by Thomas Kingsmill Abbott.