Metaethics encompasses the study of the nature of moral values, the role of reason and emotion in moral decision-making, and the relationship between moral principles and individual actions.

Moral cognitivism posits that moral statements express objective truths that can be known through reason, independent of personal preferences or cultural influences.

Deontology, also known as duty-based ethics, emphasizes the importance of following moral rules and principles, regardless of the consequences of one's actions.

Virtue ethics emphasizes the importance of developing virtuous character traits, such as honesty, courage, and compassion, as the foundation for moral action.

Consequentialism, also known as teleological ethics, evaluates the morality of an action based on its consequences or outcomes.

Consequentialist theories prioritize the maximization of happiness or well-being as the primary moral consideration.

Deontology emphasizes the importance of acting in accordance with reason and moral principles, regardless of the consequences of one's actions.

The principle of universalizability, often associated with Immanuel Kant, states that an action is morally right if it can be rationally justified to all rational beings.

Virtue ethics emphasizes the importance of acting in accordance with one's own values and beliefs, as well as developing virtuous character traits.

The principle of double effect states that an action is morally permissible if it is intended to produce a good outcome, does not produce any harmful side effects, or the good outcome outweighs the harmful side effects.

Intuitionism emphasizes the importance of acting in accordance with one's own conscience and moral intuitions, rather than relying on moral rules or principles.

Moral particularism posits that moral principles are not absolute and universally applicable, but rather are relative to specific situations and contexts.

Emotivism posits that moral statements express subjective feelings and emotions, rather than objective truths.

Moral relativism posits that moral values are relative to specific cultures and societies, and there is no objective or universal standard of morality.

Egoism posits that moral actions are those that maximize one's own self-interest or benefit.