We will be considering two ways that definitions can be used to support an argument: the definition argument and the categorical evaluation. These are closely related and often used in conjunction with each other.
Let's examine a Definition Argument. Take the following claim:
Organic, in terms of food, means plants and animals raised without additives or artificial growing conditions, but it does not mean the food is healthy.
The argument here hinges on understanding the definition of the word "organic." In this case, organic is the subject of the argument. The claim goes on to base the argument on definition criteria. The claim states that two definition criteria of "organic" are "raised without additives" and "raised without artificial growing conditions." However, it also states that "healthy" is not a definition criterion, which means something can be organic without being healthy.
Some of you might be thinking, "Well, what do they mean by 'artificial'?" or "What do they mean by 'healthy'?" If you find yourself questioning other definitions in the claim, that's great. That means you understand why definitions are so important to persuasive or analytic arguments. You could certainly write an argument on the definition of either term.
A categorical evaluation can be a helpful way to organize a definition argument. In a categorical evaluation, you define a subject by placing it into a category based on specific criteria. Here is a thesis statement for a categorical evaluation:
Though it omits hormones and antibiotics, organic ice cream remains unhealthy because it contains high levels of fat and sugar, while offering little nutritional value.
Here we have a subject - organic ice cream - and a category - unhealthy. Presumably, unhealthy things often contain similar criteria - high levels of fat and sugar, low nutritional value, and industrial additives. Organic ice cream might not contain industrial additives, but, because it meets the other two criteria, it can still be considered unhealthy.
Think of the thesis for a categorical evaluation as an equation -
X (subject) is (is not) a Y (category) because of criteria A, B, and C.
In our example, X = "organic ice cream" and Y = "unhealthy". The criteria are A) high levels of fat and sugar, B) low nutritional value, and C) industrial additives.
A good way to test your thesis is the change the subject (X). Are other things we consider unhealthy (Y) full of sugar and/or fat, low in nutrition, and made with industrial additives?
Fast food hamburgers (X) are unhealthy (Y) because they contain high levels of fat (A), low nutritional value(B), and are full of chemical preservatives(C).
Of course, you can have more than three category criteria (A, B, C, D...).