Unless of course one is serving cake, the classically educated mind will rarely ever divide something into more than two or three. This rule of logic as strange to some ears as it may be is loaded with profound truth and good thinkers will defy it almost never.
For example if a lecturer begins his lecture by saying “There are seven points” or “There are seventeen points I would like to make in this lecture,” he will in “a single blow,” by so saying defeat the ability of the average hearer to comprehend his lecture.
The fact of the matter is that most things are divided into either two or three, and if there are more than two or three one can, upon further investigation, discover that these “more” result from further subdivisions of a thing that was already divided into two or three. For example the ten commandments first come from a division of two (i.e. Commandments concerning the love of God, and neighbor) and then each of these parts may be divided into three (e.g. commandments concerning love in thought word and deed).
Those who are inclined against this logical rule, to wit “the rule of two or three,” will not be able to understand most things of any significance. Let’s start with something that really matters- food! The rule of three is of supreme importance here, from the way a meal should be divided (appetizer, entree, dessert) to the number of meals in the day (breakfast, lunch, dinner) to the content of the main course (meat, greens, and carbs of some sort!) No dinner is complete without three things. Ignore this rule and one’s dinner guests will go away from you table with a feeling that something was missing! Ignore this classical rule and in a relatively short time you will find yourself with few friends who will accept your dinner invitations!
Think of the greatest works that serve as food for man’s soul. The Bible is divided into two! (and then one might wonder what how the various books within each part are divided). Take for example the four Gospels (first a division of two and then a division of three) Look at any given work in the Bible. St Matthew’s Gospel provides an excellent example of a work that is divided into three. Without finding these divisions one can scarcely lay claim to anything but a superficial understanding of the text!
Imagine the student in Theology not knowing the threefold division of the Summa Theologica. Imagine the student of literature not knowing the divisions in the Divine Comedy. Imagine the student of Geometry not knowing the divisions of Euclid’s The Elements. “Oh Horror, horror, horror!” (Macbeth Act II.3)
Think of the way a government is divided. Think of Saint Boethius’ division of the sciences. Nay even more… Think of the way reality itself is divided (things that are wholly material, things that are material and spiritual, and things that are wholly spiritual) Think of man himself (body and soul). Think of the hierarchy of soul (vegetable, sentient, rational)
That great sage and philosopher. That father of progress of the human mind. That fiery friend to wisdom – Heraclitus was he who said “This is wisdom to speak the truth and act according to nature giving ear thereto”
Well for anyone who desires wisdom, it is an inescapable truth that to understand things and speak about things in a way that makes them comprehensible to others one must find the natural divisions in things- and these divisions will for the most part be either into two or three.
What is the threefold division of St. Matthew’s Gospel?
I should have given that division- unfortunately I do not have a copy of St Thomas’ division of the Gospel of St Matthew, but his division is simply
1) Christ coming into the world
2) Christ in the world
3) and Christ going out of the world
Again- I wish I had his words and his actual points of division with chapter numbers to make this more specific. Nonetheless, I think this is a useful way to look at the Gospel as a good starting point certainly.
Christ Himself divided the Old Testament into three: Law, prophets, and psalms (Luke 22:44).