The thing about moral discussions is that they are about morality. Morality was set up by God; therefore, He is the Prime Authority on these issues. The Catholic Church, as the institution set up by Christ to teach what He taught the Apostles and protected in Her teachings by the Holy Spirit, is the “vicar of moral authority.” So, saying that God said so, when He did in fact do so “publicly” (recorded for all to read in the Bible), is not at all the same as saying my mother said so. My mother can be wrong, God cannot be.
(I will admit that once having determined that God did indeed condemn onanism we would then have to work on the ramifications of that, why did God condemn it and whether the extension of that condemnation to abc is justifiable, etc. but I do not think that you can typify what I wrote as a mere appeal to authority.)
And your proposed solution, to discuss a Catholic dogma without referencing specific church’s dogma? The only place that leads to is religious indifferentism, well, this part of my religion is not important, and neither is that part, gee, I guess I’m just left with all the bits that everyone else will agree with!
In discussions I have had on more theological topics, I have seen people do things like this: Prove X from Scripture. Well, the thing is, some of those topics are nuanced and are taught more from Tradition* or you can only understand it through Tradition, but the other person refuses to accept anything other than the Bible.
Well, that’s sort of like saying, Prove this physics thing using only biology. I cannot “prove” Catholic teaching from *outside *of Catholic beliefs and understandings, I have to use Catholicism to prove it. I can give pragmatic reasons why something the Catholic Church teaches is useful, but looking at it from that point of view ultimately skews our understanding–you can only take that so far.
So I can “prove” something to someone who accepts the same standards of proof which I accept. Maybe I would run into a devout Catholic who happened not to know about the prohibition on abc–I could explain it to her. But I cannot explain it to you, for example, because you do not accept the same sources of information that I do.
In a court of law, the appeal to authority *can *be made, and often is: You should do X because the higher court ruled Y in a similar instance. And that higher court may well have ruled that way because of some other case in a parallel court, and so on. (Oddly enough, US law is built on English law, which is based on previous decisions… originally made using Catholic thinking.)
So I come to the conclusion that this is (yet another!) area in which all that I, at least, can do is to explain our position, not prove it. IE: abc is wrong because God condemned Onanism, and the reason that He condemned Onanism is that it frustrated the end of the sexual act, which is what abc does, so it too is wrong. That’s as far as I can go. (Altho consider this: suppose a married couple used condoms, but only during the fertile period. They would not be committing a sin outside the fertile period because they would be doing nothing at that point to frustrate the end of the act. Does that help?)
So I don’t think it is *dishonest. *I think that when people start off at different points, they each have to accept that, and allow the other to present the points from their point of view, and then if any debate goes on, it would have to start from the initial point of disagreement rather than be about something further along the trail of thinking. For me, God is very much really *there, *and very much affects how the world works. I see too many people trying to justify immorality by excluding God from a place where He ought to be. And of course I see God through the lens of Catholic theology.
And even then, it may have to be looked at like this: given your premises, I see the logic of what you are saying. I disagree only because my premises are different. I think that for one person to say that something has to be proven along lines outside the purviews of the antecedent thinking is asking too much. So we would end up talking like this: as a Catholic, I see this and that; As a Lutheran, I see something else.
*which is not regular tradition like it’s traditional for Western Catholics to make the Sign of the Cross a certain way but the body of teachings which come down to us from Christ