Lessons From: Aristotle's System of Logic

How to use Aristotle's Logic to be a better student

Teacher's Day is tomorrow here in Mexico, so before we indulge in learning about the man who possibly was the greatest teacher of all time, we will learn about Aristotle, a student of Plato,  who himself was a student of the aforementioned teacher, Socrates. Besides being one of the most prolific students Plato had, having created the first comprehensive system of Western Philosophy, and when he left his teacher's academy at the age of 37, he was requested by Phillip II of Macedon to tutor his son, Alexander the Great. Being a teacher, in fact, gave him many opportunities and supplies, with which he opened a library in the Lyceum, and although a big part of his monument was devoted to his teacher, he eventually left Platonism for empiricism, and indeed, he was one of the first to attempt to develop a scientific method, and many of his findings couldn't either be confirmed or rejected until into the 19th century. His teachings on ethics were pretty much influential in Judeo-Christian philosophy, but were eventually ignored due to the rise of Kantianism and other philosophies, but we can talk about virtue ethics in another time.

Today we will see a version of Aristotle's system of logic that will be pretty easy to understand, and once you do, you'll be able to apply it to your life. He believed that logic was the instrument we used to understand anything, and he developed what was known as categorical logic, widely accepted throughout even the 19th century, in which he asserted that the way we use the subject-predicate form is the primary expression of truth, and the way we use language can eventually be used to paint a picture of the world.

Using the Categories

In Categories, he establishes three ways that predicates can relate to each other in meaning: homonymy, synonymy, and paronymy, sometimes written as equivocal, unequivocal, and derivative. As you can predict, homonymy implies entirely different explanations, for example, "His wife cheated on him, he's pissed," and "He's had too much to drink, he's pissed." Synonymous is basically using the same predicate with the same meaning, like "Paintings are pretty," or "Statues are pretty." Paronymy is when one predicate branches out from the meaning of another, for example, "He is very well-learned," and "His knowledge of Aristotelian logic is that of a well-learned man." (That's going to be you by the end of this post).

These relationships between predicates are important when you relate them to the ten categories of things. The most important is substance, for it describes the thing in itself, and is separated into primary substance, which is the individual thing itself, and secondary substance, which is the species or genera in which the individual thing belongs. The other nine are quantity, quality, relative, where, when, being in a position, having, acting on, and being affected by, and their function is simply to describe what separates this individual substance from the others. Basically, the first step to thinking logically like the man himself is being able to actually describe the world that you're living in, and although the focus is universal, the universe is found in the particulars.

Plato points to ideas, Aristotle is grounded in reality

Because what you see is generally a result of your perception, and not the thing in and of itself, if through the Categories you can create various propositions about an object which combines or separates its concepts, and these actually correspond to the object itself, you can say that you've made a truthful statement. If you can correctly apply the categories, you can make logical deductions of the world around you, as all knowledge, acording to Aristotle, comes from what is already known. Say, for example:

• All humans are mortal
• All Athenians are human
• Therefore, all Athenians are mortal

• All dogs are mammals
• All mammals have fur and breastfeed
• All dogs have fur and breastfeed

How can we apply this?

It's pretty simple. If you were to summarize what Aristotle said in a sentence, it would basically be: Name things as they are and build on it. This also helps you create false assertions, for through the use of logic, you cannot simply invent a fact nor attribute characteristics to an object that it does not really have. All in all, knowing this will at least let you pay attention to the language you use to describe the universe, so you may avoid mistakes or inconsistencies, and thus, allow you to become an excellent student of the world. 

Read more about Logic here:

https://plato.stanford.edu/entries/aristotle-logic/