The third requirement of a good thesis, that it be well supported, might more properly be considered a requirement of the essay as a whole. In any case, if the essay is to be effective--if it is to persuade readers of your thesis, or at least of your credibility--you must provide arguments that are cogent and numerous enough to satisfy the critical reader, and you must go on to support these arguments with facts and examples.
Orders of Knowledge
The fourth requirement of a good thesis is that it be relatively high in the orders of knowledge. Benjamin Bloom divides cognitive skills into five basic categories and arranges those categories (in ascending order of complexity) into the following hierarchy: comprehension, application, analysis, synthesis, and evaluation (Bloom, 204-207). In a similar hierarchy, Mortimer Adler divides knowledge into three classes: statements of facts, statements about facts, and statements about statements (Adler, 222-224). If your thesis falls at the lowest level of either of these hierarchies, your paper will be nothing more than a report or a survey. This is fine if that''''s all you intend your paper to be. But if you intend your paper to be more than a report, you must develop a thesis that is more than a statement of fact.
For example, if your "thesis" is that "In experiments conducted by the American Cancer Institue, 70 percent of the rats subjected to cigarette smoke over a two-year period died of lung cancer," your paper can hardly develop into anything more than a report about the experiments and their results. However, if you draw some conclusion from this statement of fact and make that your thesis, you advance to Adler''''s second order of knowledge: statements about facts. At this level, your thesis might be "Scientific experiments suggest a close link between cigarette smoking and lung cancer," or a less cautious assertion, "Cigarette smoking is the major cause of lung cancer." With either of these theses, you have an argument on your hands. You have made a statement that is not entirely self-evident, one that will not be universally aGREed with, one that you will have to defend. But if you risk one step further and make a statement about this statement, you generate the spark of a potentially informative, provocative, and animated essay. For example, building on the proposition that cigarette smoking causes lung cancer, you might propose that the Constitution of the United States be amended to prohibit the production and sale of cigarettes.
Adler would classify theses of this order as statements about statements. As such, they not only encourage more stimulating essays, they also allow you to develop your essay logically by referring back to statements at the two lower levels: you present arguments (statements about facts) to support your thesis, and facts and examples (statements of fact) to support your arguments. For example, to support the thesis that the Constitution should be amended to prohibit the production and sale of cigarettes, you can draw upon the argument that cigarette smoking causes lung cancer; and to support this argument, you can draw upon the fact that in ACI experiments, 70 percent of the rats subjected to cigarette smoke died of lung cancer. Thus, theses that are statements about statements allow you to develop a layered effect that is impossible to achieve in a report or survey.
