Definition #1 Marriage is between one man and one woman to bear and rear children.
A more thorough definition by three philosophers is as follows:
Definition #2 “Marriage is the union of a man and a woman who make a permanent and exclusive commitment to each other of the type that is naturally (inherently) fulfilled by bearing and rearing children together.”
I don’t necessarily want to address this topic. Many Christian leaders I know and love promote a “definition of marriage” type of argument. They’ve worked hard and been courageous where most are not (but should be). Many of these same leaders are comparing the redefinition of marriage to the legalization of abortion. They say that some of the reasons why the pro-life movement has had success is because they developed better arguments over time. I agree: better arguments need to be developed. So let’s evaluate the definition of marriage argument #1, see how is morphs into definition of marriage #2, and why neither work.
Definition of marriage arguments are appealing to Christians for the following reasons:
They offer a legal secular argument. Biblical arguments (ruled out because of separation of church and state) and moral arguments (because of precedent in a sodomy case called Lawrence vs. Texas) are legally invalid to use in court.
They offer an absolute standard by which to define marriage. This is preferable to a subjective standard, in which others would just respond our definition does not apply to them.
They are less offensive. These arguments don’t directly address same-sex couples. They aren’t saying anything directly negative about gay people.
They restrict marriage to only moral sexual relationships, that which is between one man and one woman.
My main problem with these arguments, no matter how appealing, is that they are not invalid. One could show this with either counter-arguments or analogies. Analogies compare different, but in some way, related things. The comparison is made to something the person offering the argument understands to be true. Since they understand the truthfulness of one thing, it is easier to explain the truth of another. Many advocates from same-sex marriage reject all analogies against their view while using them to promote their view. This is cherry picking and prohibits such advocates from truly understanding their own position. They claim those who disagreement with them are ignorant, and some are, but they are calling the kettle black, guilt of the same thing they accuse in others.
The typical and easiest response to definition of marriage #1 is to respond with an analogy like, “What about elderly people? Should they be allowed to marry?” Elderly heterosexual marriages are different from young heterosexual marriages. The young can procreate (unless there is a biological problem) but the elderly cannot (by biological design called menopause). All advocates of this argument understand that the elderly should be allowed to marry. The analogy is valid and shows procreation is not necessary for marriage.
“But no problem” says the definition of marriage advocate. The elderly couple still exhibits the structure or type of procreative marriage that young couples do. Now this is a very similar but new argument, definition of marriage #2. The three philosophers use the phrase “of the type”. Their argument does not claim there needs to be actual procreation. It is the structure or type, not results, that really matters. Definition of marriage #1 has now changed in favor of definition of marriage #2.
This “structure or type” language is abstract and difficult to understand, but Girgis, George, and Anderson give us the only analogy I’ve heard to help make their point clear. They say a baseball team may not win a game but they are still a team. By comparison, although an elderly couple may not procreate (or win) they are still a valid married couple (a baseball team).
When evaluating an analogy, the goal is not to point out some differences and declare “disanalogy.” Of course there are differences – analogies compare different things. The goal is to be fair and understand how the analogy relates to an argument. So let’s relate their analogy to professional baseball. I’m doing this because marriage is the big leagues of romantic relationships. It is not appropriate to equate marriage to a little league team where the kids mostly play just for fun. So let’s say someone wanted to form a baseball team made up of 70 year old men to play Major League Baseball. This has never happened because there is no point. It would not be a valid MLB team. No owner will invest millions in it. Nobody will manage them. No spectators want to see a team guaranteed to lose every game. Even the players wouldn’t be interested. But elder couples are interested in marriage dispite they can’t win (have kids). In fact, most are happy they can’t win. Most would be horrified if they did.
So here is an alternative argument: “Only morally good relationships should be promoted.”
What I like about this argument:
It offers a secular argument. Secular people have morals too. There are sexual relationships that they find immoral. If they are going to condemn Christians for having moral standards, they are to condemn themselves as well.
It establishes common ground. All people have moral standards and it is commonly understood that differences are expected. Having different moral standards does not automatically make other people bad people (haters or bigots).
It offers an absolute standard. This is because absolute moral laws exist (for example, it’s wrong to murder others for fun). This helps lead into an opportunity to talk about the Ultimate Law Giver, which is God.
It addresses the root of the issue: morality. Marriage is really a symptom. For example, what if the Department of Education where to offer free condoms at proms throughout the country? Would Christians say, “Since it doesn’t involve marriage, we’re ok with that.” No, it’s immoral to promote per-marital sex and Christians should oppose such efforts.
It is broad enough to address non-marital relationships, as the prom example shows.
What I don’t like about this argument:
It won’t work in court. But I’m not a lawyer. My concern is not a court of law but the court of public opinion. I’m concerned with the large and increasing number of people who mistakenly think to oppose gay rights is hateful and bigoted. This needs to be dispelled if we are going to be able to share the love of God with people, the Gospel.
It is rather offensive. Contrary to many peoples conception, most conservative Christians don’t like offending gay people. Focusing on marriage and avoiding addressing the morality of homosexuality is more appealing. But it does not address the root issue which is one reason we continue to lose ground.
While absolute moral laws exist, getting secular people to understand this because they are rooted in the Ultimate Law Giver is a rare occurrence.
Honest arguments have a purpose: to persuade of the truth. This is the goal of Christians concerning marriage/morality. Definition of marriage arguments were developed to provide a secular legal defense in court. These arguments did not work, in part, because they are not valid. Just as pro-life arguments developed and improved over time, marriage/morality arguments need to do the same. Despite advances in the pro-life movement, if Roe vs. Wade were challenged at the Supreme Court today, the pro-life side would still lose. We cannot do much about the courts but we can do much about the court of public opinion. We need to change, adapt, and speak the truth in love.
 Harvard Journal of Law & Public Policy, Vol 34, Sherif Girgis, Robert P. George, Ryan T. Anderson, p246.