One of the little tics that Catholic opponents of same-sex marriage have developed is to refer to it as "marriage." As in this from the USCCB's latest letter to Congress:The blog writer then goes on to point out that Catholics often use phrases like polygamous marriage or incestuous marriage without the scare quotes--so why put them around same-sex "marriage?" Clearly polygamous marriage or incestuous marriage also don't fit the sacramental model, so why reserve the scare quotes for same-sex "marriage?"The movement to redefine marriage to include two persons of the same sex (a.k.a. same-sex "marriage") has changed the law substantially toward that end, at both the state and federal level, and it has become increasingly clear that laws like ENDA have been instrumental to those changes.The point would seem to be that because marriage by definition cannot be between persons of the same sex, it is necessary to use quotation marks lest anyone imagine that we are acknowledging that such a thing can or could exist. And, moreover, that since marriage is a sacrament in the Catholic church (this year's very Catechetical Sunday theme), the word itself must be kept free from pollution.
It's a good question, and it deserves a good answer. I'm not, of course, a Catholic apologist or theologian, so if my answer fails to be as good as it ought to be I will hope for correction from those more qualified to address these matters--but here's my offering:
Marriage, as the Church understands it, is both a natural and a supernatural state. As a natural state it originates in the Garden of Eden, with God's command to Adam and Eve to be fruitful and multiply, to fill the earth and to subdue it (Gen 1:28). But after the Fall, human beings sometimes failed to live according to the natural state of marriage. Polygamy, incest, and even divorce/remarriage were examples of human failings in regard to natural marriage.
But even as these things represented failings, they also did not alter the key reality at the heart of marriage: marriage was, and is, ordered toward the physical unity of man and woman in that act which alone among human sexual behaviors is potentially capable of producing new human beings. That act is, of course, called sexual intercourse.
The polygamist erred in believing it possible to engage in this act with a multiplicity of women without changing the morality of the act. The incestuous tribe erred in taking as husband or wife a person too closely biologically related to themselves. The divorced/remarried person erred, and still errs, in making a promise of fidelity, exclusivity, and permanence to one person--and then turning around and making the same promise a few years later to someone else. But none of these people errs by redefining marriage in such a way as to make sexual intercourse between the spouses not only unnecessary, but indeed, physically impossible.
A same-sex couple cannot engage in sexual intercourse. They can, of course, perform a variety of sex acts on and with each other, but none of those acts has ever been considered to lie at the heart of what marriage is (and, indeed, some of them are forbidden even to married people from a Catholic moral perspective). But that act which alone among human acts is potentially capable of creating a new human life is not an act which they can engage in together.
The Church has always taught, and continues to teach, that people who are not capable of the act of marriage, that is, of the act of sexual intercourse, cannot be married--even if they are heterosexual. That is, a heterosexual man who is physically incapable of the marriage act, or a heterosexual woman who is physically incapable of the marriage act, cannot enter into a valid marriage even with a member of the opposite sex, from the Church's point of view. It should be noted that this same thing does not hold true for a husband or wife who becomes incapable of the marriage act at some time after the marriage. But if, at the time they seek to marry, one or both spouses is not physically capable of the marriage act, they cannot marry. It should be noted, here, that the impediment refers only to the ability to engage in the marriage act, that is, sexual intercourse--a marriage is not invalid, nor is it rendered invalid, if the couple can engage in sexual intercourse but are infertile. There is a lot of misunderstanding about this from the same-sex side of the argument; the way to understand it is to recognize that the gift of new human life is a total gift from God, Who is the Author of life, and Who may chose to bless one family abundantly with children while asking another family to carry the cross of infertility for a time, or even for the whole of their married lives. But the God Who blessed Sarah, and Elizabeth, and Hannah with children when they were thought to be barren can also give life where that was not thought possible--so long as the couple is capable of engaging in the one act of all human actions which has the potential of resulting in a child.
At this point, some of my same-sex attracted opponents will argue that I'm making it sound as if marriage is all about sex! My answer to that is--well, it is. Not, of course, in the sense that sex is the only thing married people ever do or think about or desire, but in the sense that the life of physical unity and its results in terms of the little gifts of love who wander around the house needing diapers one minute and driver's ed the next (from the perspective of many parents)--yes, marriage is about the sexual unity of husband and wife, and the great blessings this fruitful unity can produce, the precious gift of new souls for the Kingdom of Heaven, entrusted for a time to a mother and a father who are only too aware of their own failings and shortcomings.
Are polygamy, incest, and serial divorce serious attacks against the love and unity of the married couple and the family? Yes, they are--but they aren't, at their root, so much an attack against marriage as a grave distortion of it. If sacramental marriage is a mirror image of the mystical union of Christ and His Church, then these distortions of marriage are like a funhouse mirror reflection--containing, here and there, glimpses of the truth, but too twisted and bent to be recognized.
And same-sex "marriage" is, to these, the empty frame of a mirror against a blank wall, simply because it does not contain any recognizable aspect of what the concept marriage means at all. With no sexual complementarity, with no possibility of engaging in the marriage act of potentially-reproductive sexual intercourse, with no reflection of the mystical union of Christ and His Church, what does the relationship of two people of the same gender have in common with marriage, anyway? That it involves two people (most of the time)? That those two people are romantically and physically involved? Those two criteria also describe a whole host of other human relationships which do not aspire to be called marriage, and indeed, which would not seek the term provided they had the slightest understanding of it.
When Catholic writers put the scare quotes around same-sex "marriage" (as I often do), it's not done to be snide or insulting (or at least, I don't mean it that way, ordinarily). It's done, instead, to point out that calling the pairing up of two same-sex people a "marriage" is to ignore the sexual reality that has existed at the heart of the concept of marriage from the earliest human history, a reality that has prevailed in the understanding of that concept in every major civilization that has ever existed. Even when distortions like polygamy have occurred, those distortions did not deny the importance of sexual intercourse or of the potential producing of children--far from it.
But same-sex "marriage" advocates do deny the importance of sexual intercourse to the concept of marriage. They also deny the importance of child-bearing, motherhood and fatherhood as complementary concepts, the capacity for sexual union as a central reality of marriage, and other such ideas.
To the same-sex "marriage" advocate, two men or two women can "marry" because there are two of them and because they are romantically and physically involved. Philosophically speaking, this is not unlike declaring that a slice of bread is the same thing as a chocolate chip cookie, because both are baked and made primarily of flour--ignoring the role that yeast plays in one, and that sugar and chocolate play in the other. But anyone who crumbles a slice of bread over a bowl of ice cream, or tries to place ham, mustard, and cheese between two chocolate chip cookies, is unlikely to buy that the superficial similarities of bread and cookies outweigh the many important and intrinsic differences.
In a word, I place scare-quotes around same-sex "marriage" because it involves such a difference in the definition of the word marriage from the one I, and most people in human history, have understood that I find the word out of place in context. If I were to write of a chocolate-chip-cookie ham "sandwich" I would use scare quotes, too.