All of these three theories share the same conclusions, which are as follows:

(a) we are never justified in believing that moral claims (claims of the form "state of affairs x is good," "action y is morally obligatory," etc.) are true and, even more so

Moral error theory holds that we do not know that any moral claim is true because

(iii) since we are not justified in believing any claim we have reason to deny, we are not justified in believing any moral claims.

Traditionally, normative ethics (also known as moral theory) was the study of what makes actions right and wrong. These theories offered an overarching moral principle one could appeal to in resolving difficult moral decisions.

One major trend in contemporary virtue ethics is the Modern Stoicism movement.

Objections to ethical intuitionism include whether or not there are objective moral values (an assumption which the ethical system is based upon) the question of why many disagree over ethics if they are absolute, and whether Occam's razor cancels such a theory out entirely.

Kant's three significant formulations of the categorical imperative are:

One thing that clearly distinguishes Kantian deontologism from divine command deontology is that Kantianism maintains that man, as a rational being, makes the moral law universal, whereas divine command maintains that God makes the moral law universal.

Photograph of Jurgen Habermas, whose theory of discourse ethics was influenced by Kantian ethics

Care ethics contrasts with more well-known ethical models, such as consequentialist theories (e.g. utilitarianism) and deontological theories (e.g., Kantian ethics) in that it seeks to incorporate traditionally feminized virtues and values that—proponents of care ethics contend—are absent in such traditional models of ethics. These values include the importance of empathetic relationships and compassion.

Starting from the premise that the goal of ethical philosophy should be to help humans adapt and thrive in evolutionary terms, Kropotkin's ethical framework uses biology and anthropology as a basis – in order to scientifically establish what will best enable a given social order to thrive biologically and socially – and advocates certain behavioural practices to enhance humanity's capacity for freedom and well-being, namely practices which emphasise solidarity, equality, and justice.

A more specific question could be: "If someone else can make better out of his/her life than I can, is it then moral to sacrifice myself for them if needed?" Without these questions, there is no clear fulcrum on which to balance law, politics, and the practice of arbitration—in fact, no common assumptions of all participants—so the ability to formulate the questions are prior to rights balancing. But not all questions studied in applied ethics concern public policy. For example, making ethical judgments regarding questions such as, "Is lying always wrong?" and, "If not, when is it permissible?" is prior to any etiquette.

People, in general, are more comfortable with dichotomies (two opposites). However, in ethics, the issues are most often multifaceted and the best-proposed actions address many different areas concurrently. In ethical decisions, the answer is almost never a "yes or no" or a "right or wrong" statement. Many buttons are pushed so that the overall condition is improved and not to the benefit of any particular faction.

Military ethics involves multiple subareas, including the following among others:

Ethics of nanotechnology is the study of the ethical issues emerging from advances in nanotechnology.

Ethics of quantification is the study of the ethical issues associated to different forms of visible or invisible forms of quantification.