Philosophers today usually divide ethical theories into three general subject areas: metaethics, normative ethics, and applied ethics. Metaethics investigates where our ethical principles come from, and what they mean. Are they merely social inventions? Do they involve more than expressions of our individual emotions? Metaethical answers to these questions focus on the issues of universal truths, the will of God, the role of reason in ethical judgments, and the meaning of ethical terms themselves. Normative ethics takes on a more practical task, which is to arrive at moral standards that regulate right and wrong conduct. This may involve articulating the good habits that we should acquire, the duties that we should follow, or the consequences of our behavior on others. Finally, applied ethics involves examining specific controversial issues, such as abortion, infanticide, animal rights, environmental concerns, homosexuality, capital punishment, or nuclear war. By using the conceptual tools of metaethics and normative ethics, discussions in applied ethics try to resolve these controversial issues. The lines of distinction between metaethics, normative ethics, and applied ethics are often blurry. For example, the issue of abortion is an applied ethical topic since it involves a specific type of controversial behavior. But it also depends on more general normative principles, such as the right of self-rule and the right to life, which are litmus tests for determining the morality of that procedure. The issue also rests on metaethical issues such as, "where do rights come from?” and what kind of “beings have rights?” Aristotle conceives of ethical theory as a field distinct from the theoretical sciences. The principal idea with which Aristotle begins is that there are differences of opinion about what is best for human beings, and that to profit from ethical inquiry we must resolve this disagreement. He insists that ethics is not a theoretical discipline: we are asking what the good for human beings is not simply because we want to have knowledge, but because we will be better able to achieve our good if we develop a fuller understanding of what it is to flourish. In raising this question, what is the good?
Ethics in ancient times signified moral philosophy (philosophia moral is) generally, which was also called the doctrine of duties. Subsequently it was found advisable to confine this name to a part of moral philosophy, namely, to the doctrine of duties which are not subject to external laws (for which in German the name Tugendlehre was found suitable). Thus the system of general deontology is divided into that of jurisprudence (jurisprudentia), which is capable of external laws, and of ethics, which is not thus capable, and we may let this division stand.
Aristotle is not looking for a list of items that are good. He assumes that such a list can be compiled rather easily; most would agree, for example, that it is good to have friends, to experience pleasure, to be healthy, to be honored, and to have such virtues as courage at least to some degree. The difficult and controversial question arises when we ask whether certain of these goods are more desirable than others. Aristotle's search for the good is a search for the highest good, and he assumes that the highes
t good, whatever it turns out to be, has three characteristics: it is desirable for itself, it is not desirable for the sake of some other good, and all other goods are desirable for its sake. Aristotle argued that virtues are good habits that we acquire, which regulate our emotions. For example, in response to my natural feelings of fear, I should develop the virtue of courage which allows me to be firm when facing danger. Analyzing 11 specific virtues, Aristotle argued that most virtues fall at a mean between more extreme character traits. With courage, for example, if I do not have enough courage, I develop the disposition of cowardice, which is a vice. If I have too much courage I develop the disposition of rashness which is also a vice. According to Aristotle, it is not an easy task to find the perfect mean between extreme character traits.