The four explanatory factors (aka four causes) Aristotle described can be used to explain marriage in a time in which people have forgotten what marriage is. The ancient book of Genesis provides the explanation, so it’s not a recent attempt to promote an agenda. Societies through the ages have implicitly followed the explanation, which may have led to complacency concerning what marriage is all about.
18 The Lord God said, “It is not good for the man to be alone. I will make a companion for him who corresponds to him.” 19 The Lord God formed out of the ground every living animal of the field and every bird of the air. He brought them to the man to see what he would name them, and whatever the man called each living creature, that was its name. 20 So the man named all the animals, the birds of the air, and the living creatures of the field, but for Adam no companion who corresponded to him was found. 21 So the Lord God caused the man to fall into a deep sleep, and while he was asleep, he took part of the man’s side and closed up the place with flesh. 22 Then the Lord God made a woman from the part he had taken out of the man, and he brought her to the man. 23 Then the man said,
“This one at last is bone of my bones
and flesh of my flesh;
this one will be called ‘woman,’
for she was taken out of man.”
24 That is why a man leaves his father and mother and unites with his wife, and they become a new family. 25 The man and his wife were both naked, but they were not ashamed.
The material factor is male and female: no companion who corresponded to Adam was found, unlike the animals who already had males and females. Without male and female sexes, there is no marriage.
The efficient factor is a voluntary union “of the flesh” (as the more literal translations have it), i.e., sexual intercourse. Without such a “conjugal act” the marriage is unconsummated. Without the possibility of such a union, there is no marriage.
The formal factor is a lifelong commitment, “until death do us part”. Although there is the possibility of divorce for cause (e.g., unfaithfulness), without an intention for a lifelong relationship, there is no marriage.
The final factor is the various purposes for marriage, including companionship, fulfillment of sexual desire, generation of offspring, nurturing of a family, and stability for society. The listing of these purposes does not limit the purposes of marriage; it only indicates some of what marriage can mean. Those who argue that a particular purpose could (or could possibly) be met in other ways are missing all the purposes of marriage.
Defenders of marriage have put too much stock in nailing down the purpose of marriage – that is only one factor of marriage; there are three other factors to consider. Until those who wish to redefine marriage meet the other explanatory factors, they have failed and marriage, real marriage, is the same as it always was. Legal fictions do not change reality. Marriage is still a voluntary union of one man and one woman for life.