I tried to introduce this concept a few times before, during the many years I have been around. For a short time it was followed. The new posters do not know about it, and they keep on repeating the same errors, over and over again. The principle is about the proper way of making a meaningful argument. Using just a few words, it says:
Always argue on the playing field of you opposition.
Examples:
When talking to a Protestant, don’t ever try to refer to the Cathecism, or try to refer to the infallibility of the Pope, or the authority of the Catholic Church. These arguments are meaningless to a Protestant. Your only option is to argue based upon Sola Scriptura. Nothing else is convincing to a Protestant.
When arguing with an atheist, never try to bring up the Bible, the sacred tradition, the Cathecism, the infallibility of the Pope, or the authority of the Catholic Church. You only waste your time, and your opponent’s time. If you want to make a convincing argument, use only rational, secular methods. And your starting point should always be fully secular. Otherwise your arguments are wasted. Your conversation partner will not accept it.
You are not only free, but strongly advised to bring up these sources to clarify your position. It is always helpful to have a clear understanding of what you believe in. But don’t think that you delivered an argument, because you did not. Of course I am not naive, and I don’t think that this advise will be followed for a long time. Eventually it will be forgotten, even if it might be followed for a short time. I would like to see this as a “sticky”, to cut down on meaningless posts, but I don’t think this will happen. But as long as I am around, I will refer to it. When I see a post contrary to this principle, I will not go into details, but I will refer to it as a violation of the Spock principle.