Meta-ethics, about the theoretical meaning and reference of moral propositions and how their truth values (if any) may be determined;
Normative ethics, about the practical means of determining a moral course of action;
Applied ethics, about how moral outcomes can be achieved in specific situations;
Descriptive ethics, also known as comparative ethics, is the study of people's beliefs about morality;
According to Tomas Paul and Linda Elder of the Foundation for Critical Thinking, "most people confuse ethics with behaving in accordance with social conventions, religious beliefs, and the law", and don't treat ethics as a stand-alone concept.[2] Paul and Elder define ethics as "a set of concepts and principles that guide us in determining what behavior helps or harms sentient creatures".[2] The Cambridge Dictionary of Philosophy states that the word ethics is "commonly used interchangeably with 'morality' ... and sometimes it is used more narrowly to mean the moral principles of a particular tradition, group, or individual."[3]
Meta-ethics is a field within ethics that seeks to understand the nature of normative ethics. The focus of meta-ethics is on how we understand, know about, and what we mean when we talk about what is right and what is wrong.
Meta-ethics came to the fore with G.E. Moore's Principia Ethica from 1903. In it he first wrote about what he called the naturalistic fallacy. Moore was seen to reject naturalism in ethics, in his Open Question Argument. This made thinkers look again at second order