“The friendship between man and wife,” wrote Aristotle in his Nicomachean Ethics, “seems inherently in us by nature. For man is by nature more inclined to live in couples than to live as a social and political being.”

The essential point he is making here, which is in danger of being lost in the modern world, is that marriage is fundamentally natural rather than political. In his Politics, Aristotle reinforces this statement when he states that “man is an animal more inclined by nature to connubial than political society.”

Aristotle was a meticulous student of nature. And as a philosopher, he knew how to place things in their proper order. He understood, therefore, that marriage — with its personal satisfactions, its intimacy, its security and its potential for generating offspring — is naturally superior to the more tenuous and far less personal relationships that are political and social. For much of the same reasons, Aquinas could state that the best of all friendships is that between a loving husband and wife.

Common experience should be enough to convince us that the bond of matrimony is far more secure and durable than any relationship one might have between himself and society. Marriage is natural, whereas political arrangements are conventional. Therefore, marriage has a built-in inclination toward personal fulfillment that is both original and universal.

A critical question, however, remains. Why is it that marriage, rooted in nature as it is, so often ends in failure? St. Thomas Aquinas was concerned about this question in the 13th century. He reasoned that “nature” means two things: In the first instance, it refers to a necessary connection between the natural thing and its end. Aquinas uses the simple example of fire moving upwards. Fire cannot help doing anything other than moving in this particular direction. It is compelled by nature to do so.

Marriage relates to “nature” in the second meaning. In this case, what is natural does not achieve its end of necessity. Marriage provides a basis and an inclination, but it will not achieve its end without the husband and wife nourishing its development with love and care.

To put the matter more concretely, marriage demands the ceaseless application of virtue and intelligence in order to meet the unpredictable challenges that life and society present. A vessel may be seaworthy, but it will not reach its destination unless it is steered in the right direction. Marriage, despite its naturalness, is no guarantee of happiness. It must be cultivated, a task that, at times, can be most demanding.

The Church is wise in understanding that marriage is a sacrament that is nourished by God himself. No political arrangement has ever been regarded as sacramental.

“And they lived happily ever after” does not automatically apply to marriage. No one would deny its difficulties, restrictions and inconveniences. Yet these pale in comparison with the great benefits that marriage and the family confer.

The great poet Johann Wolfgang von Goethe put marriage in the proper perspective when he wrote the following:

“Marriage is the beginning and summit of civilization. It tames the brute, and even the most civilized one has no better opportunity to prove that he is civilized. Marriage must be indissoluble; for it brings so much happiness that any unhappiness here or there is completely outweighed by that.” Goethe certainly recognized the share of inconveniences that marriage brings: “It may at times be inconvenient, this I can well believe — and this should be so. Aren’t we also married to our consciences, which we often would gladly get rid of because it is much more inconvenient than any husband or wife could ever be?”

If marriage fails, it is not because it lacks a natural basis. Rather, when it fails, it does so because it is not nurtured. Nature is what the spouses are given; the nurturing is up to them. It is easy to sentimentalize marriage. But it is also easy to trivialize it. It is sentimentalized when nurture is disregarded. It is trivialized when it is uprooted from nature and treated as a mere contract. Marriage remains, however, a synthesis of bedrock nature and firm commitment.

Donald DeMarco is a senior fellow of Human Life International.

He is professor emeritus at St. Jerome’s University

in Waterloo, Canada, and an adjunct professor at

Holy Apostles College and Seminary in Cromwell, Connecticut.