Originally posted by kingdanwa
I'm not sure what I was expecting, but I feel a bit disappointed by your responses. Perhaps if I had put forward a specific position, you would have felt more comfortable pointing out its flaws. But I'm sincerely curious about how others actually define marriage, and on what basis.
One reason the question is hard to answer is because you haven't specified whether the debate will be addressing the issue from a normative
perspective or a descriptive
If the question is a descriptive one, what you are investigating is the set of characteristics exhibited by actual marriages -- marriages being those things that various people might denote by the term "marriage" or those things that they would concede fall within their notion of the concept. This is essentially an empirical question, resolved by analyzing observations about the way the world is.
If the quesiton is a normative one, what you are investigating is whether there is a notion of marriage that people ought to adopt, and what properties would be shared by such marriages. This is essentially an analytical question, resolved by appeaing to fundamental principles about what people ought and ought not do.
To cite the teachings of Jesus in a descriptive debate is largely irrelevant; to cite the statues of Vermont is largely irrelevant in a normative debate. A descriptive debate can only be fruitful once all parties agree on what facts and observations about the world are true; the debate is a matter of who is employing the most faulty analysis about those facts. A normative debate can only be fruitful once all parties agree on fundamental principles governing what people ought and ought not do; again, the debate here will be a matter of demonstrating superior analysis from those principles.
For example, a person living in 1800 and a person living in 2000 could not have a fruitful debate about the claim "Black people in the U.S. have the right to vote" if its propositional content is taken to be descriptive, since they cannot agree on the elementary facts -- namely, the actual law. However, they could very well have a fruitful debate if the claim's propositional content is taken to be normative; there is no reason both people couldn't have the same basic ideas of what people ought and ought not do; their debate might consist in determing whether those priciples entailed preventing black people from voting or insuring that black people have the same civil rights as white people, etc.
By contrast, two people living today could very well have a descriptive debate about whether black people have the right to vote in the U.S.; they both would likely agree that the body of U.S. law governs the issue, and they would also likely agree on what statutes constitute the law. The debate would be in interpreting the law. (In this example, it's pretty trivial, but in practice this constitutes the bulk of civil litigation.) However, if those two people are, say a white supremecist and Al Sharpton, then a debate about the normative content of the claim is likely to be fruitless, since they have fundamentally different views about what people ought and ought not do.
So, to get more precise responses, it's best to
1) State whether you are posing the question in a descriptive sense or a normative sense. That is, whether you want to know about the way the world is, or the way it ought to be.
2) If it's descriptive, state the empirical scope of your question; e.g., over all of human history vs. now, in the U.S. vs. the whole world, in Christian circles vs. across all religions. Or if it's normative, what sorts of ideologies you want to hear from (using analysis from free-loving hippies to debate against a conservative Lutheran is going to be an instance of a fruitless normative debate described above).
The Philosophy section here offers a good briefing if you are intereseted in arming yourself further. Citing Hume while pounding the podium might at least make your opponent a bit nervous.