Correspondingly, the epistemology of ethics divides into cognitivism and non-cognitivism; a distinction that is often perceived as equivalent to that between descriptivists and non-descriptivists. Non-cognitivism may be understood as the claim that ethical claims reach beyond the scope of human cognition or as the (weaker) claim that ethics is concerned with action rather than with knowledge. Cognitivism can then be seen as the claim that ethics is essentially concerned with judgments of the same kind as knowledge judgments; namely about matters of fact.

The ontology of ethics is concerned with the idea of value-bearing properties, i.e. the kind of things or stuffs that would correspond to or be referred to by ethical propositions. Non-descriptivists and non-cognitivists will generally tend to argue that ethics do not require a specific ontology, since ethical propositions do not refer to objects in the same way that descriptive propositions do. Such a position may sometimes be called anti-realist. Realists on the other hand are left with having to explain what kind of entities, properties or states are relevant for ethics, and why they have the normative status characteristic of ethics.

Descriptive ethics

Descriptive ethics is a value-free approach to ethics which examines ethics not from a top-down a priori perspective but rather observations of actual choices made by moral agents in practice. Some philosophers rely on descriptive ethics and choices made and unchallenged by a society or culture to derive categories, which typically vary by context. This can lead to situational ethics and situated ethics. These philosophers often view aesthetics, etiquette, and arbitration as more fundamental, percolating "bottom up" to imply the existence of, rather than explicitly prescribe, theories of value or of conduct. The study of descriptive ethics may include examinations of the following:

Ethical codes applied by various groups. Some consider aesthetics itself the basis of ethics – and a personal moral core developed through art and storytelling as very influential in one's later ethical choices.

Informal theories of etiquette which tend to be less rigorous and more situational. Some consider etiquette a simple negative ethics, i.e. where can one evade an uncomfortable truth without doing wrong? One notable advocate of this view is Judith Martin ("Miss Manners"). According to this view, ethics is more a summary of common sense social decisions.

Practices in arbitration and law, e.g. the claim that ethics itself is a matter of balancing "right versus right," i.e. putting priorities on two things that are both right, but which must be traded off carefully in each situation.

Observed choices made by ordinary people, without expert aid or advice, who vote, buy, and decide what is worth valuing. This is a major concern of sociology, political science, and economics.

Applied ethics

Applied ethics is a discipline of philosophy that attempts to apply ethical theory to real-life situations. The lines of distinction between meta-ethics, normative ethics, and applied ethics are often blurry. For example, the issue of abortion can be seen as an applied ethical topic since it involves a specific type of controversial behaviour. But it can also depend on more general normative principles, such as possible rights of self-rule and right to life, principles which are often litmus tests for determining the morality of that procedure. The issue also rests on meta-ethical issues such as, "where do rights come from?" and "what kind of beings have rights?"

Another concept which blurs ethics is moral luck. A drunk driver may safely reach home without injuring anyone, or he might accidentally kill a child who runs out into the street while he is driving home. The action of driving while drunk is usually seen as equally wrong in each case, but its dependence on chance affects the degree to which the driver is held responsible.

Specific questions

Applied ethics is used in determining public policy. For example, the following would be questions of applied ethics: "Is getting an abortion immoral?" "Is euthanasia immoral?" "Is affirmative action right or wrong?" "What are human rights, and how do we determine them?" and "Do animals have rights as well?"

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.

Post-Critique Ethics

The 20th Century saw a remarkable expansion of critical theory and its evolution. The earlier Marxist Theory created a paradigm for understanding the individual, society and their interaction. The Renaissance Enlightened Man had persisted up until the Industrial Revolution when the romantic vision of noble action began to fade. Humanism, which enshrined the nobility of man, lost validity particularly after the Great War and the Nazi Holocaust.

Modernism, exemplified in the literary works of Virginia Woolf and James Joyce wrote out God, then anti-humanists such as Louis Althusser and Michel Foucault and structuralist such as Roland Barthes presided over the death of the author and man himself. As critical theory developed in the later 20th century post-structuralism queried the very existence of reality. Jacques Derrida placed reality in the linguist realm stating ‘There is nothing outside the text’ while Jean Baudrillard theorised that signs and symbols or simulacra had usurped reality, particularly in the consumer world. This concept is explored in the postmodernist film Blade Runner.

Post-structuralism and postmodernism are both heavily theoretical and follow a fragmented, anti-authoritarian course which is absorbed in narcissistic and near nihilistic activities. Normative issues are generally ignored. This has led to some opponents of these later movements echoing the critic Jurgen Habermas who fears ‘that the postmodern mood represents a turning away from both political responsibilities and a concern for suffering’.

David Couzens Hoy says that Emmanuel Levinas’s writings on the face of the Other and Derrida’s mediations on the relevance of death to ethics are signs of the ‘ethical turn’ in Continental philosophy that occurs in the 1980’s and 1990’s. Hoy clarifies post-critique ethics as the ‘obligations that present themselves as necessarily to be fulfilled but are neither forced on one or are enforceable’.

This aligns with Australian philosopher Peter Singer’s thoughts on what ethics is not. He firstly claims it is not a moral code particular to a sectional group. For example it has nothing to do with a set of prohibitions concerned with sex laid down by a religious order. Neither is ethics a ‘system that is noble in theory but no good in practice’. For him it would be more of the reverse. He agrees that ethics is in some sense universal but in a utilitarian way it affords the ‘best consequences’ and furthers the interests of those affected.

Hoy in his post-critique model uses the term ethical resistance. Examples of this would be an individual’s resistance to consumerism in a retreat to a simpler but perhaps harder lifestyle, or an individual’s resistance to a terminal illness. Hoy describes it in his book Critical Resistance as an individual’s engagement in social or political resistance. He provides Levinas’s account as ‘not the attempt to use power against itself, or to mobilise sectors of the population to exert their political power; the ethical resistance is instead the resistance of the powerless.

Hoy concludes that The ethical resistance of the powerless others to our capacity to exert power over them is therefore what imposes unenforceable obligations on us. The obligations are unenforceable precisely because of the other’s lack of power. That actions are at once obligatory and at the same time unenforceable is what put them in the category of the ethical. Obligations that were enforced would, by the virtue of the force behind them, not be freely undertaken and would not be in the realm of the ethical.

In present day terms the powerless may include the unborn, the terminally sick, the aged, the insane, and animals. It is in these areas that ethical action will be evident. Until legislation or state apparatus enforces a moral order that addresses the causes of resistance these issues will remain in the ethical realm. For example, should animal experimentation become illegal in a society, it will no longer be an ethical issue. Likewise one hundred and fifty hundred years ago, not having a black slave in America may have been an ethical choice. This later issue has been absorbed into the fabric of a more utilitarian social order and is no longer an ethical issue but does of course constitute a moral concern. Ethics are exercised by those who possess no power and those who support them, through personal resistance.