The Art of Division - My Notes on 4.1 of 'The Reasonable Person" by Mark Grannis

The technique of division begins with a general whole and proceeds in the splitting of the whole into lesser parts. "Division if the separation of a logical whole into inferior parts according to some principle, known as the principle of division." Grannis gives a good example of this in subdividing the 10 Categories of Aristotle. 

Grannis mentions two benefits this skill of dividing can offer us. First, it helps us understand the scope of broad categories when we know what all is implied in them. In other words division helps us know the whole better. Second, it also helps us understand the parts better by creating relationships that we can analyze between them. In other words, division also helps us know the parts better. 

But in order to make good divisions we need to know the limits or extent of the unified whole. "The most important thing to know about the whole is that we have to understand its full extension before we can make a good division." Likewise, "Apart from our inability to divide things of which we are totally ignorant, a somewhat subtler point about the logical whole is that we have to know its boundaries." 

When dividing we want to aim at the essence of things, not at accidental or coincidental similarities as much. And so therefore there is an inherent logic to these divisions and can be called its "principle of division". "The principle of division is the criterion that distinguishes each inferior part of a division from the others, without placing any part outside the whole." 

The most famous example of division is that of Porphyry's Tree, who created a division of substances. Interestingly one can begin from the top down, such as in division, but also from the bottom up in "categorization." 

Here are some examples to practice division: Book/music/movie genres, sports, food, candy, automobiles, boats, etc.