I have often been asked by my students: "Why won't the Church allow homosexual persons to be married?" They typically argue now that denying them such a right is an instance of unjust discrimination. "They too," it is pointed out, "can fall in love with one another, just like heterosexuals."
I can only reply by pointing out that it isn't that the Church will not allow homosexual couples to be married. Rather, it is impossible for two people of the same sex to be married. By definition, marriage is "a joining of two into one flesh, one body" (Cf. Gn 2, 24). A definition expresses the nature of something, as "rational animal" expresses the nature of man, or "three sided figure" defines or expresses the nature of a triangle. Definitions are not determined by human beings, but are discovered by them as they penetrate into the nature of the thing known. So too with regard to the institution of marriage. It is not possible to alter the definition of marriage any more than it is possible to alter the definition of a triangle, a bird, or a human being.
Let me explain. Love is, of its very nature, both unitive and effusive. Love tends to union, and we see this in gestures such as the handshake, the embrace, the kiss, and various other kinds of touch. But love is also effusive, that is it is not self-contained. It tends to communicate itself, express itself, pour itself out and move beyond itself. A love that is not fruitful is no love at all. In other words, love is not selfish, but selfless.
Conjugal love (married love) is also both unitive and effusive (procreative). It is impossible for two human persons to become any more united than in the one flesh union that is the sexual act. In this act, the two become reproductively one organism. They become one body. That is why the sexualact is, of its very nature, a marriage act; for the two actually become one body, one flesh in the act of sexual union, and one flesh union is precisely what is intended in marriage.
Because conjugal love is unitive, it is also effusive, that is, it is procreative. It is by virtue of this union that new life is begotten. The two give their entire bodies, including their own fertility, to one another. New life is the result of the one flesh union of the two, and this new life is a testimony, a visible expression, of the one flesh union of the parents (how often do we see the child with its mother's eyes, or its father's nose, etc.).
And so a marriage is consummated by the couple's first act of sexual intercourse. After this first act, they are consummately married. If they cannot consummate the marriage, they can remarry if they so choose, for they have not been able to actually become "one flesh, one body".
It should be obvious at this point that a homosexual marriage is not possible. Two women cannot become one flesh, one body. It is a physical impossibility, and marriage is a physical phenomenon (there are no married angels). It is also impossible for two males to be married. It is impossible for two persons of the same sex to give their bodies completely to one another. A male cannot receive the fertility of another man, nor can a woman receive the fertility of another woman. Only a man can receive the total gift of another woman, and only a woman can receive the total bodily gift of another man. The intercourse that homosexual males might choose to engage in is not at all a joining of two into one flesh (much less a mutual and total self-giving), for the two do not become reproductively one organism (a male is reproductively incomplete). Rather, this action is merely a mimicking of the sexual act, not an authentic instance of it. For the unitive good of the sexual act regards a physical union of persons, not parts.
Consider now the Supreme Court decision to change the definition of marriage to include gay and lesbian couples and the implications of believing that we can arbitrarily do so.
Marriage: a joining of man and woman into one flesh, one body, through an intention, publicly witnessed, in which the two establish one another as unique, irreplaceable, and non-substitutible.
A Supreme Court Justice takes it upon himself (or herself) to erase woman and replace it with man, or vice versa. This move further entails the elimination of joining of two into one flesh, one body (since no one can deny that male and male or female and female do not become one body). Now on what basis is one justified in making such a change? We can be certain that the basis is not the natural law; for two people of the same sex cannot be one flesh. If the basis is not the natural moral law, then it is the will. In other words, if the basis is not something outside of us, such as the real nature of marriage, then it can only be something inside of us, namely the will). In other words, the decision to alter the definition is arbitrary and capricious.
Consider now a Muslim, who might wish to have more than one wife. Since our understanding of marriage is no longer based on the requirements of natural law, but rather upon will -- for we arbitrarily and capriciously changed the definition of marriage -- what is to stop anyone from altering this new definition further? For example, in Canada there is the Charter of Rights and Freedoms, which requires Canadians not to discriminate on the basis of religion. What, we may ask, is going to prevent polygamy from becoming legal? Any decision to prevent polygamy from becoming legal would seem to be just as arbitrary and discriminatory. Taking this a step further, it is hard to see on what basis we can deny, for example, the right of an uncle to marry his niece, or a girl to marry her first cousin. And in light of what Princeton Ethics professor Peter Singer argues about bestiality, on what basis will we deny a person the right to marry his or her pet? The answer is that there is no basis at all, once we shift from a natural law basis to the will.
Part of the reason that both sides of this debate find it difficult to understand one another's position has to do, I am convinced, with their respective modes of thinking. One side is thinking in a linear way (quantitatively) while the other side is thinking in a multi-dimensional way (qualitatively). For example, some people, including politicians, argue that opening up marriage to gay couples will not alter heterosexual marriage in any way. Let's examine this contention. Below is an example of what I mean by linear thinking:
Linear Thinking
__________*__________*__________*__________*__________*
(__1 inch___*__1 inch___*___1 inch__*)
[Male/Female (Heterosexual Marriage)]
From the linear point of view, what is added to one end does not change or alter what exists at the other end. For example, adding an inch to a 25 inch line will not affect the already existing inches. All it will do is render the whole line 26 inches in length. The pre-existing 1 inch, or 2 inch, at the beginning of the line, will remain unchanged in themselves. So the parts will remain what they are. The above contention that opening up marriage to gay couples will not affect heterosexual marriage is rooted in linear thinking.
But we would argue that there is a distinction between "logical being" and "real being". Contrary to Descartes, what exists outside the mind exists differently inside the mind. In the extramental world, quantity is an aspect of "things" that have an essential quality (but mathematical entities are pure quantities). In other words, quality is more fundamental. We are looking at this issue not from a linear point of view, but rather from what we would designate as a "multi-dimensional" or qualitative point of view. Consider the diagram below:
Multi-Dimensional Thinking
Animal:
--Bird
--fish
--Dog
--Human
In the above diagram, we have various species of animal. The "genus" in this case is "animal", while the species are "Bird", "Fish", "Dog", and "Human". Now the definition of an animal is "living sentient creature". So, whatever is living and sentient is an animal. The specific characteristics of each species, though, are outside of the essence of animal. For example, birds have wings, but dogs do not. Hence, "wings" does not belong to the essence of animal -- otherwise all animals would have wings, or whatever does not have wings would not be an animal. Fish have gills, but birds and dogs and human beings do not. In other words, "gills" is outside the essence of animal -- otherwise all animals would have gills, or whatever did not have gills would not be an animal.
Returning now to the question of unisex marriage. Consider the diagram below:
Multi-Dimensional Thinking
Marriage:
--Male/Male
--Male/Female
--Female/Female
Note that what is happening here is that a gay relationship is becoming a "species" of marriage. Thus, marriage is the "genus". When this happens, the very meaning of the genus marriage changes. Let me explain. Just as what was specific to a species of animal lies outside the essence of animal (i.e., wings, gills, rationality, barking, etc), so too what is specific to each of the above relationships (male/male, female/female, male/female marriage) would remain outside of the essence of marriage. Now, traditionally, heterosexual marriage has always been understood to be a joining of two into one flesh, one body. As such it is a unitive and procreative community. As a procreative relationship, it is an institution (an organization that exists for the public welfare); for society proceeds from the family. But a male/male relationship is essentially non-procreative. It is impossible for two males to even intend to generate human life from the substance of their bodies. A gay relationship is a friendship, and friendships are not by their very nature procreative. Likewise, a female/female relationship is essentially non-procreative; for it is impossible for two females to even intend to generate human life from the substance of their own bodies (Artificial insemination is not an instance of generating human life from the substance of their bodies. They would need the seed of a man who is outside of that relationship to do so). A gay relationship is a personal friendship that has reached a genital level. Only a heterosexual relationship can be a unitive relationship in the sense of a joining of two into one reproductive organism, and thus only a heterosexual relationship can become an essentially procreative one (an infertile married couple are merely unable to realize their procreative potentialby virtue of some medical impediment). So, if a male/male relationship and a female/female relationship can be called a species of marriage, then it follows that "procreation" and "one flesh union" are no longer part of the very essence of marriage. In other words, marriage has nothing essentially to do with children. The intention to procreate new life becomes "accidental" (outside the essence) to the meaning of marriage. This means that what renders marriage a public and social institution has become merely accidental or non-essential. Married couples can beget and raise children if they so choose, but intending to do so and actually doing so is in itself no longer something that belongs to the very idea of marriage.
We would argue that reality is not linear, but qualitative and multi-dimensional. Opening up marriage to gay relationships indeed changes the nature of marriage, relegating it from an institution to a private relationship, that is, from an objective reality that once established cannot be undone any more than one can undo the fact that one is a parent, to a purely subjective reality that begins and ends in the will of the couple (friendships are established in the will, and they are brought to an end by the will of the two). Such a change in thinking will have very definite social repercussions. As Maggie Gallagher argues, marriage will no longer be a shared public norm. Moreover, one can only wonder how such changes will help the decline of marriage that began in the early 60s. For the reason for the decline in marriage has been precisely a radical Individualism that argues for the primacy of the individual as opposed to the family. The introduction of unisex marriage is merely a consequence of this very Individualism (marriage as a private affair). As such, it cannot help reverse the decline in marriage but can only perpetuate it by institutionalizing our confusion about what marriage really is.
It is always seriously wrong to unjustly discriminate against a person on the basis of his or her sexual orientation. This cannot be emphasized enough. Every member of the human community is a member of the redeemed. To look with contempt upon another human being merely on the basis of a sexual orientation that he or she did not choose is to persecute Christ (Mt 25, 45; Cf. Mt 5, 21-24). But it is not an instance of unjust discrimination to deny homosexual persons the right to be married, for there is no natural right to establish something that is in fact physically impossible. Marriage is more than legal sanction for two people to live in the same home and sleep in the same bed. It is a publicly professed intention by two to become one body until death dissolves the union (for at death, there is no more body, hence no marriage). An authentic marriage, once established, is not something that man, by his own will, is able to dissolve. If marriage is a natural institution, and not a merely conventional one, then it is no more possible to change the definition of marriage than it is to change the definition of a plant. If we believe we can change its definition, then we treat marriage as if it is fundamentally a human artifact. The world has always believed that marriage was "from the beginning" (Cf. Mk 10, 6ff).