How do we know what that good is? How do we understand how many margaritas on a warm day, is to many margaritas? This requires an understanding of objective truth. St. Thomas Aquinas assures us that it “belongs to the ruling of prudence to decide in what manner and by what means man shall obtain the mean of reason in his deeds
.” Prudence is considered the queen of the Cardinal virtues as it enables us to see things rightly in regards to practical matters. It comes from the latin word prudentia which is properly translated practical wisdom. Therefore, the prudent man, in his day to day actions acts wisely, making decisions that are good not only for himself but for others. Very often today, we tend to think of prudence as a bad thing or as being overly cautious. The western tradition of understanding prudence has in fact been lost. to the point that those who exercise practical wisdom were once referred to as “prudes.”
Prudish behavior by today’s standards can often be right reason in action. If prudence were simply knowledge of rightly ordered things it would never lead to virtue. Our mind can be filled with all of the right things, it can discover the right course of action, however, until the will acts on them, there is no prudence.
In ordering margaritas on a warm summer day, perhaps more than two margaritas impairs a particular man’s ability to think clearly and choose well. A prudent man knows that two margaritas is his limit. He desires to maintain the fully functioning capacity of his reason and free will and as a result he decides that after two margaritas he will switch over to water or if necessary call it a night. He makes this decision based on his knowledge, but most importantly he acts on what he knows. This action, this refusal to have more than two drinks, is a result of his knowledge of the damage that can be caused to himself and those around him when he drinks to much. For this reason he can be said to be a man of prudence.
To many margaritas can affect not only our own lives, but the lives of those around us. It can adversely affect our relationships. St. Thomas refers to the virtue governing these rightly ordered relationships as justice. He adopts a simple phrase “suum cuique,” which means to each his due. What is due to others? According to one of the precepts of the natural law, one should “do unto others as you would have done unto you (Mt. 7:12.) This was the entire point of the ten commandments. In reality, does the average person need to be told “thou shalt not kill?” It is nearly universally accepted by men that their own lives our valuable, and that they would not like to have some one take it from them. A reasonable person can deduce from this, that other human beings value their lives and would not like to have them taken from them. Therefore, it is reasonable to deduce that what is due to others is a respect for their lives. This is reaffirmed by Jesus in the gospel, when he says “love your neighbors as yourself (Mt. 22:39).”
We live in communion with other human beings, in our families, friendships, and at work. It is impossible to escape. Justice therefore is what is due to those with whom we are in communion. What is due, must first be considered from the natural order of things and deals primarily with our relations with other men as St. Thomas says “The proper matter of justice consists of those things that belong to our intercourse with other men.”