Descriptive and prescriptive theses
A descriptive thesis makes a claim about how things are. A prescriptive thesis makes a claim about how things should be. (Think of a doctors prescription, which tells you what you should do to get well, as opposed to a diagnosis, which simply describes your illness.) You can agree with someone about how things are even if you dont share their values. But you cant agree on how things should be unless you share at least one value. Therefore, prescriptive theses deal with questions of values, ethics or morality. And as I said, such theses are not allowed in this class.
Here are some features of each type of thesis.
A descriptive thesis
- makes an is statement
- appeals to evidence that anyone (given enough training) can observe and confirm
- appeals to logic that anyone (again, given enough training) can test and confirm
- deals in measurement, analysis, interpretation, explanation
A prescriptive thesis also uses evidence, logic, measurement, analysis, interpretation and explanation. However, unlike a descriptive thesis, it also
- makes a should statement
- appeals to shared values or moralsassessments of what is good and bad.
Some examples of descriptive theses:
- Racism in this country has historical roots in the theft of indigenous land and
the enslavement of African peoples to work that land (Lowen, 143).
- Global warming is real and is caused by human activity, not natural changes in the climate.
- American popular music is rooted in the folk tradition of African Americans.
- The United States does not offer equal economic opportunity to all of its citizens.
Some examples of prescriptive theses:
- We all need to work hard to overcome the legacy of slavery and racism.
- Global warming must be stopped!
- Music teachers should teach their students about the African American roots of American popular music.
- The United States economic system should be reformed so that everyone has equal economic opportunity.
In some cases a descriptive thesis may strongly imply a prescriptive argument as well (as in most of the examples above). However, note that one can agree or disagree with the descriptive thesis regardless of how one feels about the moral question. For example, some people agree that global warming is real and caused by human activity, but they do not believe it is a bad thing.
Remember: prescriptive theses (theses about values, ethics, morality, or shoulds) are not allowed in this class.
Loewen, James. Lies My Teacher Told Me: Everything Your American History Textbook Got Wrong. New York: Touchstone, 1996.