QUALITIES AND CLASSIFICATION
Qualities allow us to identify similarities and differences between things. When we identify similar qualities among things, we generalize---grouping them together because they are like each other in certain ways. When we identify different qualities among things, we specify---separating things from each other based upon the ways in which they're different.
Similarities and differences among things are always qualitative. That is, similarities and differences are determined by particular qualities that identify one thing as like (or different from) another thing. We use words that name qualities for sorting and classifying things into categories. If we consider just the main class category of apples, for example, it means that we are using certain qualities to generalize similarities among among various kinds of these things so that we can call them all apples. When we want to know more specific information, we must consider those qualities that will separate out the differences among differing types of apples: sweet or sour; red or yellow; Jonathan or Delicious.
Apples in general are a class (or category) of things. They may differ in respect to color and sweetness, but they're all similar to each other in general ways--such as shape and how they grow. So, when we're talking about the general category of apples, we group them based on general qualities that all apples have in common with each other. When we specify, we name qualities that point out differences and we use these names to sort the apples into sub-categories of different kinds of apples.
If, on the other hand, we want to compare apples and oranges, the general category that would include both of these things is fruit. Naming a thing fruit is more general than naming it apple, just as apple is a more general term than Winesap. There are many kinds of fruit--including apples--just as there are many kinds of apples--including Winesaps.
Getting from fruit to apples to Winesap apples involves naming qualities that specify differences. Getting from Winesap apples to apples to fruit, requires us to name qualities that generalize based upon similarities....