Your third error is that your institutional view of apostolic succession is contrary to the very Westminster Standards that you are championing. The standards make no such distinction between de jure and de facto churches, but say that the catholic church is made up all those that profess the true religion and their children. . . . The standards recognize both the unity of the church and the particularity of the churches. There are more and less pure churches. The test is their purity of faith and practice, not their supposed line of descent.
This is, of course, an argument against the idea that when denominations are separated from each other, the side that is correct in remaining separate (assuming there is one) retains de jure authority while the other side loses it. For example, the RPCNA is separated from the PCA. One of the reasons for separation is that the RPCNA practices exclusive psalmody while the PCA doesn't. Simplifying the situation for the moment and assuming these two were the only existing denominations and that this was the only issue that divides them, the RPCNA would be right in remaining separate from the PCA but not vice versa because exclusive psalmody is the correct biblical practice. Their separation would entail that each denomination accuses the other of being schismatic and rejects its de jure legitimacy and authority, and in this case the RPCNA would be right, and therefore the RPCNA should be regarded as possessing de jure authority but not the PCA.
One of the underlying presbyterian principles here is that one must do things "decently and in order" (1 Cor. 14:40), and one cannot claim authority when one's authority is attained illegally and schismatically. My interlocutor quoted above, on the other hand, believes, apparently, that it doesn't matter how a denomination came into being; so long as the denomination is sufficiently orthodox, it possesses de jure authority. He doesn't seem to have a place in his thinking for the historic and biblical concept of schism.
At least, he seems not to have such a concept in his thinking when we are talking abstractly about separated denominations he has grown used to. But I'll bet he'd recognize the concept if the situation were to occur more locally and closer to home. Imagine this scenario in a local church:
Pastor: Hi there, Bob! How are things going today?
Bob: Hi, Pastor! Things are going well. By the way, did I tell you that I have decided to be a pastor?
Pastor: Really? Would you like to come with me to the next presbytery meeting so that you can come under care and begin your training towards licensure?
Bob: No, that won't be necessary. I'll be a pastor tonight. I've called some of the congregation to come over to my house at about 6:00 this evening (and you are invited too--that's actually why I've come to see you), when I will declare myself a pastor. After that point, I'll receive into membership whomever wants to join me, and then we'll be a separate congregation. I'd like to do that so that we can have a congregation that will celebrate Christmas, since I think that is important, and you and the rest of the session of this congregation don't seem very keen on it.
Pastor: But you can't do that! You can't just declare yourself a pastor all by yourself and draw people away from our current congregation to join you! That's schismatic! If you want to be a pastor, you've got to go through the proper channels by being officially licensed and ordained by the presbytery, and you've got to stay in full communion with the church.
Bob: I thought you would probably say something like that. Well, we can argue all day about the proper biblical method of starting a church, but I don't want to get into that right now. We'll just have to agree to disagree. But it's OK. You don't have to think of my new church as being schismatic, because, aside from the relatively minor difference over Christmas, the creeds of our churches will be nearly identical. We'll be quite sufficiently orthodox to be considered as true a church as any you could think of.
Pastor: I'm glad you're planning on being fairly orthodox, but that's not enough to claim the authority of the church. If you don't do things decently and in order, you're being schismatic.
Bob: Are you saying you won't consider us true Christians?
Pastor: I don't presume to judge your heart. But what I will say is that your course is wrong, and your church will lack legitimacy and proper authority if you establish it in this way. You might be a group of regenerated people (though I'm very concerned for you, seeing that you are taking this course of action!), and thus be a church in a de facto sense, but you won't be a legitimate church de jure, because you have founded your church improperly and schismatically.
Bob: Are you saying that you won't recognize us formally as a legitimate de jure church?
Pastor: No, absolutely not!
Bob: I think you've become confused about how the church works in the Reformed faith. You sound almost Romanist, going on about "proper authority" and "doing things legitimately" and what sounds suspiciously like "apostolic succession." But you've forgotten the Confession of Faith. After all, as it has been wisely said, "Your institutional view of apostolic succession is contrary to the very Westminster Standards that you are championing. The standards make no such distinction between de jure and de facto churches, but say that the catholic church is made up all those that profess the true religion and their children. . . . The standards recognize both the unity of the church and the particularity of the churches. There are more and less pure churches. The test is their purity of faith and practice, not their supposed line of descent." Since our new church will be basically pure doctrinally from your point of view, it will have full de jure legitimacy and full authority as a church. To say otherwise is to go back to Romanism with its idea that "if you aren't united with us and do things our way and don't have proper descent, you don't have any authority." But we're Reformed! The true church is founded on fidelity to Scripture, not on some Romanesque theory of apostolic descent!
Of course, the problem with Bob's view is that he has distorted the true meaning of the Reformed confessions and thus mutilated a proper biblical understanding of church authority. It is true that the Reformed faith places the legitimacy of a church in its fidelity to doctrine. This position was taken, biblically, in response to the false Roman claims that there can be no true church unless it has been handed down without interruption from the original churches of the apostles, that it gains its legitimacy from union with the Roman Pontiff, and that God has preserved such an infallible succession in the churches. The Reformed, on the other hand, maintained and maintain that succession can be broken, in which case a church can legitimately be formed by following Scriptural principles. They maintain that succession is not infallible. They maintain that union with the Roman Pontiff is not necessary for ecclesiastical legitimacy.
However, they do not go to the other extreme, the extreme Bob goes to, and say that there need be no concern for proper order in the church or that it doesn't matter how a church comes into being or whether it exists and acts schismatically so long as it is basically orthodox in doctrine. This sort of thinking better fits an organization like Calvary Chapel than the historic Reformed faith. Schism is not merely a Roman concept. It is a biblical concept, a historic catholic concept, and a Reformed concept. It is possible for a church to be basically orthodox in doctrine but still lack legitimacy because it was formed or exists schismatically.
I think my interlocutor would see this when we are discussing situations like that of Bob. Where a lot of modern Reformed people go wrong, however, is that they fail to apply these same principles to the broader world of denominations. Denominations, just like local churches, can be fairly orthodox in doctrine and yet still lack legitimacy because they were formed or exist schismatically. It is not "mean" or "rude" or "schismatic" or "Romanist" to declare that we have an obligation to take schism into consideration in evaluating the right to exist of the various denominations out there, and to act accordingly in choosing which denomination we ought to be a part of. To do so is simply to act in accordance with biblical and historic Reformed principles, and to properly pursue both the purity and the unity of the one church of Christ.
See more on this here.