Normative premises are assumptions about values, aims and objectives. Most normative premises are rhetorically self-evident and not susceptible to logical dispute. "Government should respect universal human rights" is an example of a normative premise. Debaters arguing from the same normative premises often disagree on the definition of key terms. In the example above, participants will likely discuss the meaning and scope of the phrase "universal human rights."
Social scientists use descriptive premises when making arguments about cultural and psychological behavior ethics. Unlike normative premises, descriptive premises do not make any moral claims. They simply describe the way that people, communities or societies behave in certain situations. Descriptive premises are not moralistic or value-laden like normative premises. Descriptive premises are the data that constitute the starting point of a social scientist's analysis of ethics-related phenomena.
According to ethics expert Dr. Richard Paul, founder of the online Center for Critical Thinking, logical analysis serves an important purpose in ethical arguments. People should not argue ethics merely from emotion or rhetoric, but rather from a basis of sound reasoning. Unfortunately, egocentrism often gets in the way of detached reasoning, as people tend to irrationally cling to beliefs despite contrary evidence. Yet, the logical flow from premises to conclusions is an important rubric for judging the veracity of an ethical argument.
Applied ethics is the science of using ethical reasoning, premises and conclusions in real-world situations. While some philosophers and ethicists limit their work to theoretical analysis, others pursue the messy world of application. Sociologists, anthropologists and psychologists often attempt to bridge the gap between theory and practice by examining how individuals and groups express their ethical values and choices in both everyday situations and those that are ethically complicated.