When I say “marriage exists in nature” – or rather “there is a certain thing that has regularly been called ‘marriage’ that exists in nature” – I am not making a historical or biological claim. I am not talking about “nature” in the sense of “natural history”.
So you
don’t mean ‘in nature’ in the way that any english speaker would understand it.
Perhaps it would help if you stated what you
do mean as opposed to what you do
not?
OK, so think about the concept of “blueness”. If I were to say that “blueness exists in nature”, I would be saying that there is a certain way things can be which is “blue”, and that all blue things have this property of blueness in common. It is plausible, at least, that blueness would continue to exist as a “way things could be” even if all blue things suddenly stopped existing.
There are several different things that you could mean by ‘blueness’ - e.g. the wavelength, the frequency or the energy of photons reflected or emitted by something. Or the physicochemical properties of something that make this so. Or indeed the internal representation inside your head of how you perceive ‘blueness’. ‘Qualia’, in other words.
For example, if the villainous DrTaffy kidnaps you and rewires your optic nerve or visual cortex so that you perceive your (previously blue) dressing gown as ‘red’ and your (previously red) spiderman underwear as ‘blue’, which now has ‘blueness’?
More to the point, what has this to do with the topic of this thread?
The most obvious link is the internal represantation. To that extent, sure there is a thing that we all recognise as the thing currently referred to as ‘marriage’, and would probably recognise as such even in a remote amazonian tribe without bridesmaids or penguin suits or wedding cakes.
But the problem here is that this is exactly where ‘civil unions’ fell down - everyone immediately recognised these as gay ‘marriages’. QED?
I think marriage is something like that. There is a certain real relation in nature, whether or not any beings ever participate in that relation: this is the relation we might call “marriage”.
Great - what is it, and why do you argue that it excludes gay couples? Again, please say clearly what you
do mean rather than quibbling about what you do
not.
So when you say that certain cultures have had gay marriages, that is completely irrelevant to the claim I am making.
How can that possible be irrelevant? Especially to
my question about how Catholics justify trying to narrow the definition of ‘marriage’?
Would you agree to the premise that morality exists objectively, independent of human opinions?
Not without a long discussion about what you mean by that, especially as you have claimed that no argument or premise can be objective. Nor do I see how this is relevant to the topic of this thread.