The Stoic School teaches that strength is a good thing. This is basic to human nature and Nature in general. Nature rewards the strongest in a species with survival and progeny. Nature is a place of struggle. The earth is a place where all animals must exert constant activity to live and must exercise great strength to get ahead. Those who lose their energy fall behind and perish. 

Human society also rewards athletes of great strength or speed. You don’t find yourself wishing you were weaker, do you? 

But, the Stoic School teaches about a strength more powerful than muscles.

First, think about an army. History shows that the most athletic soldiers do not always win. A smaller army with better strategy and equipment often defeats a larger force. Why? Second, a runner or boxer who has beaten a certain opponent previously might lose to him during the Olympics because the opponent trained harder and kept a stricter diet. Third, a weaker army can rout a greater one when the stronger flees the battle field.  Fourth, The ancient play The Suppliants by Euripides illustrates a special kind of power. In the play, the women have no physical power to retrieve the bodies of their dead loved ones who were killed in a battle, because the victors wanted them to rot in the open and be eaten by animals, so what mysterious strength empowered the mothers, wives, and daughters to win?

Our cultural grandparents called the first kind of strength “Wisdom,” the second “Temperance,” the third “Courage,” and the fourth “Justice.”

1) Wisdom is “being smart,” “thinking things through,” “making good decisions.” 

2) Temperance is self-control, self-discipline, and the ability to choose the difficult path that is good rather than the easy paths that are bad.

3) Courage means fortitude, bravery in the face of danger and pain, and risking personal safety, wealth, and reputation in the interest of something more noble.

4) Justice is doing the right thing, recognizing a higher morality than even human laws, and successfully harmonizing with Nature rather than only reading and talking about it.

The Stoic School teaches that the purpose of human life is Virtue. 

Even in human society, Nature requires constant energy to live, to be healthy, to be wise, to control yourself, to be brave, and to be fair to all.

An evidence that Nature intends mankind to be virtuous is that Nature gave humanity the potential for all these strengths. We know of no other creatures with the potential to develop the four Cardinal Virtues as we mean them here. Nature has attributes that can only be understood by those who practice wisdom, temperance, courage, and justice. We live in Nature more and more only as we grow in Virtue more and more. 

Another indication that Virtue is our purpose in life is that virtues bind us in stronger friendship with our fellow citizens, our friends, and our family. We are political animals. Nature provides no other species with a social structure anything like human society. There are no other species with commerce, technology, musical instruments, clothing, conversations, etc. anything like human society. But, along with our need to socialize in our uniquely human way, we see that virtue is what binds us together in the bonds of good faith necessary to produce thriving human societies. Individuals who practice Virtue are bound with their friends in stronger bonds of friendship and are praiseworthy among their countrymen. Those who practice vice suffer in their public and private relationships.

We call Wisdom, Temperance, Courage, and Justice the Cardinal Virtues. They remind us of the cardinal directions North, South, East, and West. With only four directions you can get from wherever you are to wherever you need to be in two-dimensional space.  In life, you need a different dimension of directions – virtues.

With the Cardinal Virtues, you can get from any circumstance you are in to where you need to be. The four virtues form a coordinate system that surely navigates you through your entire life, with “magnetic north” being the Good. Whatever crisis or reversal befalls you, the way to maintain happiness and to get where you need to be is always a combination of these four virtues.

The mother of all the virtues is Gratitude. All virtues are a combination of Wisdom, Temperance, Courage, and Justice, and those Cardinal Virtues come from Gratitude. Wisdom, Temperance, Courage, and Justice are the natural response to gratitude for what Nature has done for us, what our friends have done for us, and what our country has done for us.