I am determined to prove my professor wrong. Here is a question from a recent exam:
Using the six definitional criteria, evaluate the following definition.
A square is a closed-plane figure whose sides are all equal.
- too narrow
- unsuitable attribute
I do not believe that the right answer is offered as an option here.
I would argue that the fallacy committed in this definition is neither:
a.) obscure; the language is clear and not overly technical
b.) circular; at no point is the term used in the definition
c.) too narrow; the defined parameters do not exclude any squares
d.) unsuitable attribute; everything here refers to geometry and is suitable in describing a square
I believe that the definitional fallacy here is: "too wide". There are myriad polygons that could fit this definition besides the square. It should, in fact, be made narrower by including the parameter of having four sides or being a quadrilateral.
This was his response to my challenge of the question:
For the reason you say below the definition is too narrow by excluding polygons. 82% of the students put too narrow. I suggest focusing on exam 4-b and getting a higher square [sic] making your concerns moot. Otherwise, make an appointment to see me. You are doing well in the course, Professor X
First of all, the definition DOES NOT exclude polygons such as hexagons and equilateral triangles. Second, his statistic about other students' selections is not strong evidence and basically irrelevant, especially if the correct answer was unavailable. I really think that I am right on this one. Can anyone support my argument?
Here is wikipedia's summary of fallacies of definition for help.